WO2023207005A1 - Biosynthesis method for exogenous seed crystal-added mediated schwertmannite, as well as product and application of schwertmannite - Google Patents

Biosynthesis method for exogenous seed crystal-added mediated schwertmannite, as well as product and application of schwertmannite Download PDF

Info

Publication number
WO2023207005A1
WO2023207005A1 PCT/CN2022/128476 CN2022128476W WO2023207005A1 WO 2023207005 A1 WO2023207005 A1 WO 2023207005A1 CN 2022128476 W CN2022128476 W CN 2022128476W WO 2023207005 A1 WO2023207005 A1 WO 2023207005A1
Authority
WO
WIPO (PCT)
Prior art keywords
minerals
feooh
mineral
ferrooxidans
add
Prior art date
Application number
PCT/CN2022/128476
Other languages
French (fr)
Chinese (zh)
Inventor
党志
江锋
易筱筠
薛潮
阳月贝
王衡
曾丽娟
Original Assignee
华南理工大学
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华南理工大学 filed Critical 华南理工大学
Publication of WO2023207005A1 publication Critical patent/WO2023207005A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
    • B01J20/0225—Compounds of Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt
    • B01J20/0229—Compounds of Fe
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
    • B01J20/0274—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04 characterised by the type of anion
    • B01J20/0281—Sulfates of compounds other than those provided for in B01J20/045
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/28—Treatment of water, waste water, or sewage by sorption
    • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/103—Arsenic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C02F2101/22—Chromium or chromium compounds, e.g. chromates

Definitions

  • the invention belongs to the technical field of water treatment adsorption materials, and specifically relates to a biosynthetic method of adding exogenous crystal seeds to mediate Schreck's minerals, as well as its products and applications.
  • Heavy metal pollution widely exists in mining, mechanical processing, metal smelting, surface treatment and other industries.
  • a large amount of wastewater is generated in industrial production and discharged into surface water and groundwater without proper treatment.
  • Heavy metal pollution can cause long-term toxicity to the environment and human health through various pathways.
  • the main technologies for treating heavy metal contaminated wastewater include coagulation-flocculation, membrane treatment, chemical precipitation, ion exchange, adsorption, etc.
  • limitations such as low processing efficiency, high cost, and lack of selectivity make these processes impractical.
  • Adsorption has attracted more and more attention due to its simplicity, convenience and high removal efficiency.
  • metal oxides such as nano-iron oxide, aluminum oxide, and manganese oxide are considered to be ideal adsorbents for the removal of heavy metals.
  • Iron-based adsorbent materials have become the most widely used adsorbents due to their huge reserves, simple synthesis and environmental friendliness, and low-cost iron-based materials have attracted more and more attention around the world.
  • Schneider's mineral (Fe 8 O 8 (OH) 8-2x (SO 4 ) x •nH 2 O is an ocher-colored hydroxy iron sulfate secondary mineral formed in acidic, sulfate-rich water.
  • Shiite minerals usually only exist in extremely acidic Fe-rich and SO 4 2-- rich mine drainage environments.
  • the environmental condition window for mineralization is narrow and the yield is low.
  • the main artificial synthesis methods include hydrogen peroxide oxidation method (chemical fast method), dialysis method (chemical slow method) and microbial method.
  • Chinese invention patent CN110713224B discloses a method for preparing Schmitten minerals by dialysis. It first insulates the synthetic system at 50-70°C, and then dialyzes it at room temperature for 7 days to obtain a sea urchin-like shape close to that formed in the natural environment.
  • the sea urchin-like burr structure has a significantly weaker ability to adsorb and remove pollutants than the burr-like Schmitz mineral.
  • the microbial oxidation method can obtain Schmitten minerals with a microscopic morphology (sea urchin-like) close to those mineralized in the natural environment.
  • the microbial oxidation cycle is long, the mineral particles are seriously agglomerated, and the specific surface area is small, which limits its maximum removal of pollutants. .
  • the internal reaction zone will be protected, resulting in a reduction in its specific surface area, resulting in the inability to maximize its adsorption capacity. Therefore, researchers are committed to transforming biosynthesized Schneideria minerals to improve adsorption activity and adsorption capacity.
  • the adsorbent is greatly affected by pH when treating (loid) metals in wastewater. The adsorption effect is worse under acidic conditions than in neutral environments, and the same is true for Schmitten minerals. Therefore, the present invention wants to improve the performance of biosynthesis of Schretzite minerals in a gentle and non-biologically lethal way by adding crystal seeds (which provide more surface sites for the formation of Schretzite minerals).
  • seed crystals need to provide enough surface (i.e. growth sites) for growth, so smaller crystal particles are often used as seeds, while a very small amount of large crystals are often difficult to play a significant role in the crystallization process. Effect.
  • the required crystal seeds also need to be stable under acidic conditions, have a large specific surface area, uniform and suitable particle size, high cost performance, and have a fixed internal structure, similar to the structure and composition of Schretzite minerals.
  • For Fe ( III) and SO 4 2- have certain adsorption capacity.
  • iron oxides are commonly found in the natural environment, mainly including iron oxides and iron hydroxides (also called iron oxyhydroxide, FeOOH ) .
  • FeOOH has the advantages of large specific surface area, relatively stable physical and chemical properties and special structural characteristics, and plays an important purification role in the treatment of pollutants in the environment.
  • the FeOOH currently of concern is mainly goethite ( ⁇ -FeOOH) , tetragonal lepidocrocite ( ⁇ -FeOOH) , and lepidocrocite ( ⁇ -FeOOH) .
  • tetragonal lepidocrocite ( ⁇ -FeOOH) is a nanoparticle formed in an environment rich in chloride ions and iron.
  • ⁇ -FeOOH has a tunnel structure similar to that of Schmitten minerals.
  • the structure contains double-chain octahedrons that share edges.
  • the edge-sharing octahedrons share angles with adjacent chains, forming a channel parallel to the c- axis .
  • ⁇ -FeOOH is a nanoparticle with the advantages of non-toxicity, low cost, and good stability under acidic conditions. Therefore, under the induction of ⁇ -FeOOH specific functional groups (a large number of hydroxyl groups), inorganic substances may migrate, enrich, transform and form secondary minerals. The properties of the formed Schnitz minerals will change with the amount of ⁇ -FeOOH added.
  • the present invention systematically studied the feasibility of using ⁇ -FeOOH as a crystal seed to mediate the biosynthesis of nanoscale Schretzite minerals.
  • Our purpose is to adjust the morphology, structure and surface properties of Schmitten minerals in biosynthetic systems, increase the number of functional groups, and improve their reactivity towards heavy metals.
  • This invention has contributed to the development of high-performance adsorbents for biosynthesis and is of great significance to deepening the understanding of biosynthesis of Schneiderii minerals .
  • one of the purposes of the present invention is to provide a synthesis method of Schrezfeldt minerals with high yield; and can shorten the time of biosynthesizing Schretzite minerals. cycle.
  • the second purpose of the present invention is to enhance the performance of Shi's mineral in removing pentavalent arsenic and hexavalent chromium in acidic wastewater.
  • the Shiite mineral prepared by the invention has high yield, short synthesis cycle, low cost, good effect on As(V) and Cr(VI) pollution control in water bodies, and can be applied to the treatment of industrial wastewater such as mining.
  • a method for adding exogenous crystal seeds to mediate the biosynthesis of Strychite minerals including the following steps:
  • the density of A. ferrooxidans in the A. ferrooxidans resting cell suspension described in step (1) is 1 ⁇ 10 8 ⁇ 3 ⁇ 10 8 cells/ml; a more preferred density is 1 ⁇ 10 8 cells/ml.
  • the concentration of the ⁇ -FeOOH nanocrystal seed solution in step (1) is 0.001 ⁇ 0.1 g/mL.
  • a more preferred concentration is 0.01 g/mL.
  • the concentration of ferrous sulfate in the mixed solution described in step (1) is 20 ⁇ 160 mmol/L; a more preferred concentration is 80 mmol/L;
  • the volume ratio of the ⁇ -FeOOH nanocrystal seed solution and the mixed solution in step (1) is 2 ⁇ 128::1000; the more preferred volume ratio is (2, 4, 8, 16, 32, 64, 128 ): 1000;
  • the volume ratio of the A. ferrooxidans resting cell suspension and the mixed solution in step (1) is 1:50 ⁇ 100.
  • a more preferred volume ratio is 1:100.
  • the culture in step (2) is performed at 150 to 200 Culture in shaker at r/min;
  • the washing in step (2) is deionized water washing; the freeze-drying temperature is -30 ⁇ -45°C and the time is 12 ⁇ 36 h; and the sieving is passing through a 100 ⁇ 200 mesh sieve.
  • the preparation method of the ⁇ -FeOOH nanocrystal seed solution in step (1) includes the following steps:
  • Dissolve ferric chloride in absolute ethanol then add deionized water and mix well to obtain a reaction solution, react at 80 ⁇ 100°C for 36 ⁇ 54 hours; after the reaction is completed, centrifuge, wash, and freeze-dry to obtain ⁇ -FeOOH nanocrystal seeds; The obtained ⁇ -FeOOH nanocrystal seeds are added with water and ultrasonically dispersed to obtain a ⁇ -FeOOH nanocrystal seed solution.
  • the ferric chloride is FeCl 3 ⁇ 6H 2 O; the concentration of ferric chloride in the reaction solution is 0.2 ⁇ 0.4 Mol/L; the volume ratio of the absolute ethanol and deionized water is 1: 1-1.5;
  • the washing is with absolute ethanol and deionized water until neutral; the freeze-drying time is 12 to 36 hours;
  • the ultrasonic dispersion time is 30 to 45 minutes.
  • the preparation method of the A. ferrooxidans resting cell suspension includes the following steps:
  • the centrifugal temperature is 4 ⁇ 7°C, and the centrifugal force is 10000 ⁇ 12000 g, time is 8 ⁇ 10 minutes;
  • the volume after suspension is 1/50 ⁇ 1/100 of the culture medium.
  • the pH adjustment is to use H 2 SO 4 to adjust the pH to 2-3.
  • the above-mentioned biosynthetic method is used to synthesize Schmitz minerals that are mediated by adding exogenous crystal seeds.
  • the present invention has the following advantages:
  • the "crystal seeding method" of the present invention can directly provide crystal nuclei and provide crystal growth sites for the growth of Schmitten minerals, thus greatly shortening the induction period and nucleation period. Therefore, the present invention can shorten the microbial mineralization cycle (from the original 66h to 42h).
  • the hydrolysis mineralization of ferric iron in the comparative example without added seed crystals ended in 66 hours, while the precipitation of the present invention with added crystal seeds ended in 42 hours, shortening the microbial mineralization cycle.
  • the yield of Schmitten mineral synthesized by the present invention is high, and is significantly higher than the yield synthesized without adding crystal seeds.
  • the total output of synthetic minerals of the present invention is 8.0% to 96.7% higher than the comparative example without adding crystal seeds.
  • the Shiite mineral prepared by the present invention has a better removal effect on As(V) and Cr(VI) in water, which provides an effective way to treat contaminated wastewater rich in As(V) and Cr(VI). .
  • the present invention uses iron salt as raw material, which is simple and easy to obtain, and microbial mineralization is an effective, sustainable and low-cost synthesis method with simple process flow, convenient operation and low production cost.
  • Figure 1 is the characteristic X-ray diffraction pattern (XRD) of the Schmitten minerals and ⁇ -FeOOH nanoparticles prepared in Examples 1 to 7 and Comparative Examples of the present invention.
  • Figure 2 is a scanning electron microscope (SEM) image of Schmitten minerals and ⁇ -FeOOH nanoparticles prepared in Examples 1 to 7 and Comparative Examples of the present invention.
  • Figure 3 is an infrared spectrum (FTIR) of the Schmitten minerals and ⁇ -FeOOH nanoparticles prepared in Examples 1 to 7 and Comparative Examples of the present invention.
  • FTIR infrared spectrum
  • Figure 4 is a graph showing the ferrous iron oxidation rate of the Strychite minerals prepared in Examples 1 to 7 and Comparative Examples of the present invention.
  • Figure 5 is a diagram of ferric iron mineralization of Schmitten minerals prepared in Examples 1 to 7 and Comparative Examples of the present invention.
  • Figure 6 is a histogram showing the total production and net production of Schmitten minerals prepared in Examples 1 to 7 and Comparative Examples of the present invention.
  • Figure 7 shows the As(V) removal curves (a. Removal rate; b. Adsorption capacity) of Strychite minerals and ⁇ -FeOOH nanoparticles prepared in Examples 1 to 7 of the present invention and ⁇ -FeOOH nanoparticles at different As(V) concentrations.
  • Figure 8 shows the Cr(VI) removal curves (a. removal rate; b. adsorption capacity) of Strychite minerals and ⁇ -FeOOH nanoparticles prepared in Examples 1 to 7 of the present invention and ⁇ -FeOOH nanoparticles at different Cr(VI) concentrations.
  • Figure 9 shows the As(V) removal curves (a. removal rate; b. adsorption capacity) of Strychite minerals and ⁇ -FeOOH nanoparticles prepared in Examples 3 and 6 of the present invention and ⁇ -FeOOH nanoparticles at different pH values.
  • Figure 10 shows the Cr(VI) removal curves (a. removal rate; b. adsorption capacity) of Strychite minerals and ⁇ -FeOOH nanoparticles prepared in Examples 3 and 6 of the present invention and ⁇ -FeOOH nanoparticles at different pH.
  • Figure 11 is the adsorption kinetic curve ⁇ a.As(V); b.Cr(VI) ⁇ of the Strychite mineral prepared in Examples 3, 6 and Comparative Examples of the present invention.
  • a method for adding exogenous crystal seeds to mediate the biosynthesis of Strychite minerals including the following steps:
  • the concentration of FeCl 3 ⁇ 6 H 2 O in the step (1) is 0.2Mol/L, and the ratio of absolute ethanol and deionized water is 1:1; the resulting ⁇ -FeOOH has good crystallinity, uniform particles, and long Spindle-shaped nanoparticles about 60nm in diameter and 30nm in width.
  • the A. ferrooxidans strain was isolated and purified from the acid mine wastewater of a pyrite mine in Guangdong province, my country (preserved by the China Type Culture Collection Center, referred to as CCTCC, the preservation number is: CCTCC NO: M2013102).
  • This strain was cultured using 9K medium.
  • the culture solution was then filtered through qualitative filter paper to remove iron precipitates, and the filtrate was centrifuged at 4°C and 10,000 g for 10 minutes to collect the bacterial cells.
  • the bacterial cells were washed three times with H 2 SO 4 solution (pH ⁇ 2.5), and then suspended in H 2 SO 4 solution (pH ⁇ 2.5). Collect approximately 20 ml of bacterial suspension from 1 L of culture solution to obtain a concentrated bacterial solution (50 times).
  • the density of A. ferrooxidans is approximately 1 ⁇ 10 8 cells/ml.
  • the volume of the ⁇ -FeOOH nanoparticle solution added to the system in step (3) is 0, 1, 2, 4, 8, 16, 32, 64 mL.
  • the synthesized Schmittenberg minerals were respectively recorded as Comparative Example, Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, and Example 7, and the Comparative Example was used as a blank control group.
  • the synthesized seed crystal ( ⁇ -FeOOH) has obvious characteristic peaks, good crystal form, and high purity. It is a spindle with a length of 60 nm and a width of 30 nm. shaped particles. It can be seen from Figure 1 that the characteristic peaks of the Schretzite mineral prepared by the present invention are the same as those of previously reported minerals, and are determined to be Schretzite minerals, and the specific surface area (BET) of the example is larger than that of the comparative example.
  • the particles of the Schretzite mineral prepared by adding seed crystals are more dispersed, have more surface burrs, and have a larger specific surface area than the comparative example (the Schretzite mineral synthesized without using crystal seeds). It shows that the present invention can increase the adsorption sites of Schretzite through crystal seed induction, thereby increasing the adsorption amount of heavy metals by Schretzite.
  • the infrared spectra (FTIR) of the examples and comparative examples are shown in Figure 3. From Figure 3, it can be seen that 1647 cm -1 is caused by the deformation of water molecules, and 1078, 950, and 688 cm -1 should be attributed to the v3, v1, and v4 diffraction peaks of Schmitten mineral SO 4 2- respectively.
  • the infrared spectrum analysis results further prove that the mineral prepared by the present invention is Schmitten mineral.
  • the difference is the diffraction peak on the infrared spectrum of -OH.
  • the -OH diffraction peak position of the comparative example is at 3159 cm -1 .
  • the stretching vibration absorption of -OH from Example 1 to Example 7 The position of the peak shifts from 3159 cm -1 to 3300 cm -1 , and the intensity of the -OH diffraction peak gradually becomes larger, indicating that the seed-induced Schmitten mineral may have successfully introduced more -OH, which is beneficial to the adsorption of heavy metals.
  • the total mineral output of Examples 1 to 7 is 8.0%, 11.3%, 15.9%, 19.9%, 33.1%, and 58.3% higher than the comparative example respectively. ,96.7%.
  • the net mineral yields of Examples 1 to 7 are respectively 7.3%, 10%, 13.2%, 14.6%, 22.5%, 37.1%, and 54.3% higher than those of the comparative example.
  • the net production here refers to the production of Schmitten minerals after deducting the weight of added seed crystals, because the seed crystals may not be fully utilized and are nanoparticles. In the washed minerals, the nanoparticles have been washed away, so this is the minimum net production. Therefore, the present invention is a high-yield method for synthesizing Schmitten minerals.
  • the batch experimental reaction system for adsorbing As(V) and Cr(VI) on the Strychite minerals synthesized in Examples 1 to 7, Comparative Examples and ⁇ -FeOOH is to add 30 mL containing As(V) with a specified concentration into a 50 mL centrifuge tube. and 0.1 M NaNO 3 background solution of Cr(VI), then add 15 mg of solid sample (solid concentration is 0.5 g/L), and then place it in a shaker with a rotation speed of 180 r/min and a temperature of 25°C for 24 h. And the change of pH was adjusted by 0.1 M HNO 3 and 0.1 M NaOH. All samples were processed in three parallel groups per group.
  • Adsorption isotherm experiment Set different initial As(V) and Cr(VI) concentrations to 5, 15, 30, 60 and 100 mg/L respectively, and maintain the solution pH at 3.
  • pH adsorption experiment uses Example 3, Example 6 and comparative examples and seed crystals. Set the pH to 2, 3, 4, 5, 6, 7, and 8 respectively, and the initial As(V) and Cr(VI) concentrations are both 30 mg/L.
  • Adsorption kinetics experiment uses Example 3, Example 6, Comparative Examples and seed crystals.
  • the initial As(V) and Cr(VI) concentrations are both 30 mg/L, pH is 3, and sampling time points are set to 1, 2, 5, 10, 20, 30, 60, 120, 180, 360, 720, 1080, and 1440 minutes.
  • the Schmitten mineral prepared by the present invention has a better removal effect of Cr(VI) under acidic and neutral conditions than the seed crystal, and is not weaker than the comparative example.
  • the Examples and Comparative Examples have better Cr(VI)
  • the optimal adsorption pH of ) is 5 ⁇ 6, and the adsorption capacity of Cr(VI) gradually increases at pH 2 ⁇ 6, and the adsorption capacity of Cr(VI) gradually decreases at pH 6 ⁇ 8.
  • the ability of the seed crystal to remove As(V) and Cr(VI) is worse than that of the comparative example, and the comparative example is worse than that of the example.
  • the enhancement of the adsorption capacity of As(V) and Cr(VI) in the example is by no means the introduction of adsorption capacity.
  • the seed crystals in the present invention play a role in modifying the structure of the Schrezgen mineral synthesized in the embodiment, guiding the synthesis of the Schrezfeldt mineral, forming more adsorption active sites, or exposing More adsorption active sites improve the adsorption activity and adsorption capacity of Shiite minerals.
  • the present invention has systematically studied the feasibility of using ⁇ -FeOOH as a crystal seed to mediate the biosynthesis of nanoscale Strychite minerals.
  • the Sichite mineral prepared by the present invention has high yield, short synthesis cycle and low cost.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Analytical Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Compounds Of Iron (AREA)
  • Water Treatment By Sorption (AREA)

Abstract

Disclosed in the present invention are a biosynthesis method for exogenous seed crystal-added mediated Schwertmannite, as well as a product and an application of Schwertmannite. The method of the present invention comprises: adding a β-FeOOH nano seed crystal solution into a ferrous sulfate solution, and then adding an A. ferrooxidans resting cell suspension to obtain a mixed solution; culturing the mixed solution at 25-30°C for 42-72 h; and after culturing is ended, washing mineral precipitates, freeze-drying, and sieving to obtain exogenous seed crystal-added mediated and synthesized Schwertmannite. According to the present invention, the Schwertmannite prepared by adding an exogenous seed crystal is higher in yield, is shorter in synthesis period, and has a treatment effect on As(V) and Cr(VI) in a water body superior to Schwertmannite without using a seed crystal. In addition, the present invention has the advantages of simple, quick and efficient preparation, low cost and no secondary pollution to the environment, and can be applied to the treatment of acid mine drainage.

Description

一种添加外源晶种介导施氏矿物的生物合成方法及其产物与应用A biosynthetic method for adding exogenous crystal seeds to mediate Schneideria minerals and its products and applications 技术领域Technical field
本发明属于水处理吸附材料技术领域，具体涉及一种添加外源晶种介导施氏矿物的生物合成方法及其产物与应用。 The invention belongs to the technical field of water treatment adsorption materials, and specifically relates to a biosynthetic method of adding exogenous crystal seeds to mediate Schreck's minerals, as well as its products and applications.
背景技术Background technique
重金属污染广泛存在于矿山开采、机械加工、金属冶炼、表面处理等行业。工业生产中产生了大量的废水，未经适当处理就排入地表水和地下水中。重金属污染可通过多种途径对环境和人体健康产生长期的毒性。目前重金属污染废水处理的主要技术有混凝-絮凝、膜处理、化学沉淀、离子交换、吸附等。然而，诸如处理效率低、成本高和缺乏选择性等限制使得这些工艺不切实际。吸附作用以其简单、方便、去除效率高等特点引起了人们越来越多的关注。在广泛使用的吸附剂中，纳米铁氧化物、铝氧化物和锰氧化物等金属氧化物被认为是去除重金属的理想吸附剂。铁基吸附材料因其巨大的储量、简便的合成和环境友好性使成为应用最广泛的吸附剂，且低成本的铁基材料已经引起了全世界越来越多的关注。施氏矿物 (Fe 8O 8(OH) 8-2x(SO 4) x•nH 2O是在酸性、富含硫酸盐的水中形成的一种赭色的羟基铁硫酸盐次生矿物，具有高比表面积、表面反应活性和隧道结构，且无生物毒性，具有环境友好的优点等特点，对环境中重(类)金属的迁移和钝化有着重要影响。因而倍受地质学家和地球化学工作者的关注。 Heavy metal pollution widely exists in mining, mechanical processing, metal smelting, surface treatment and other industries. A large amount of wastewater is generated in industrial production and discharged into surface water and groundwater without proper treatment. Heavy metal pollution can cause long-term toxicity to the environment and human health through various pathways. At present, the main technologies for treating heavy metal contaminated wastewater include coagulation-flocculation, membrane treatment, chemical precipitation, ion exchange, adsorption, etc. However, limitations such as low processing efficiency, high cost, and lack of selectivity make these processes impractical. Adsorption has attracted more and more attention due to its simplicity, convenience and high removal efficiency. Among the widely used adsorbents, metal oxides such as nano-iron oxide, aluminum oxide, and manganese oxide are considered to be ideal adsorbents for the removal of heavy metals. Iron-based adsorbent materials have become the most widely used adsorbents due to their huge reserves, simple synthesis and environmental friendliness, and low-cost iron-based materials have attracted more and more attention around the world. Schneider's mineral (Fe 8 O 8 (OH) 8-2x (SO 4 ) x •nH 2 O is an ocher-colored hydroxy iron sulfate secondary mineral formed in acidic, sulfate-rich water. It has high Specific surface area, surface reactivity and tunnel structure, no biological toxicity, environmentally friendly advantages and other characteristics, have an important impact on the migration and passivation of heavy metals in the environment. Therefore, it is highly favored by geologists and geochemists. readers’ attention.
施氏矿物通常只存在于极端酸性富Fe、富SO 4 2- 的矿山排水环境中，成矿的环境条件窗口窄、产率低。目前，通过人工合成方法主要有双氧水氧化法（化学快法）、透析法（化学慢法）和微生物法。如中国发明专利CN110713224B（CN201910958408.2）公开了一种透析法制备施氏矿物的方法，它是先将合成体系在50-70℃保温，然后常温透析7天得到接近自然环境下形成的海胆状具有毛刺结构的施氏矿物； 但H 2O 2快速氧化仅需1d便可得400~500nm的球形施氏矿物(Loan et al., 2005)；而氧化亚铁硫杆菌氧化FeSO 4 在约3d后便可以得到的粒径约2μm的海胆状施氏矿物。现有合成方法存在的问题主要有：透析法合成周期太长，需要大量去离子水，在工程应用上不切实际；虽然H 2O 2快速氧化法速度快，但获得的矿物未观察到典型的海胆状毛刺结构，对污染物的吸附去除能力明显弱于毛刺状施氏矿物。微生物氧化法可获得微观形貌（海胆状）接近自然环境下成矿的施氏矿物，但微生物合矿周期较长，矿物颗粒团聚严重，比表面积小，限制了其对污染物的最大化去除。此外，李浙英等人（环境科学学报, 2011,31(3):460-467；环境科学学报, 2011,31(5):912-918）也发现与化学合成施氏矿物相比，微生物合成的施氏矿物因其毛刺的微观结构对污染物具有更高的吸附容量，且生物成矿比化学氧化法铁沉淀率更高。因此，微生物成矿作为一种有效、可持续、低成本的铁基材料合成方法，近年来受到越来越多的关注。但通过微生物方法合成的施氏矿物通常以微米级的球形聚集体形式呈现，由于较大的球形结构，内部反应区将受到保护而导致其比表面积减小，导致其吸附能力不能最大化应用。因此研究人员致力于改造生物合成的施氏矿物提高吸附活性和吸附容量。所采取的措施主要集中在控制pH、温度、形成时间和培养基等环境因素。然而，这些措施并不能有效地调节施氏矿物的结构。同时吸附剂在处理废水中(类)金属时受pH的影响较大，在酸性条件下吸附效果比中性环境差，施氏矿物也是如此。于是本发明想通过添加晶种（为施氏矿物的形成提供更多的表面位点）来温和且非生物致命的方法来改善生物合成施氏矿物的性能。 Shiite minerals usually only exist in extremely acidic Fe-rich and SO 4 2-- rich mine drainage environments. The environmental condition window for mineralization is narrow and the yield is low. At present, the main artificial synthesis methods include hydrogen peroxide oxidation method (chemical fast method), dialysis method (chemical slow method) and microbial method. For example, Chinese invention patent CN110713224B (CN201910958408.2) discloses a method for preparing Schmitten minerals by dialysis. It first insulates the synthetic system at 50-70°C, and then dialyzes it at room temperature for 7 days to obtain a sea urchin-like shape close to that formed in the natural environment. Schretzite minerals with burr structure; However, rapid oxidation of H 2 O 2 only takes 1 day to obtain 400~500nm spherical Schretzite minerals (Loan et al., 2005); while Thiobacillus ferrooxidans oxidizes FeSO 4 in about 3d After that, sea urchin-like Schreck's mineral with a particle size of about 2 μm can be obtained. The main problems with existing synthesis methods are: the dialysis synthesis cycle is too long, requires a large amount of deionized water, and is impractical for engineering applications; although the H 2 O 2 rapid oxidation method is fast, no typical minerals are observed in the obtained minerals. The sea urchin-like burr structure has a significantly weaker ability to adsorb and remove pollutants than the burr-like Schmitz mineral. The microbial oxidation method can obtain Schmitten minerals with a microscopic morphology (sea urchin-like) close to those mineralized in the natural environment. However, the microbial oxidation cycle is long, the mineral particles are seriously agglomerated, and the specific surface area is small, which limits its maximum removal of pollutants. . In addition, Li Zheying et al. (Journal of Environmental Science, 2011,31(3):460-467; Journal of Environmental Science, 2011,31(5):912-918) also found that compared with chemically synthesized Sichite minerals, microbial Synthetic Schmitten minerals have a higher adsorption capacity for pollutants due to their burr microstructure, and the biomineralization rate is higher than that of chemical oxidation iron precipitation. Therefore, microbial mineralization, as an effective, sustainable, and low-cost method for the synthesis of iron-based materials, has received increasing attention in recent years. However, Schretzite minerals synthesized through microbial methods are usually in the form of micron-sized spherical aggregates. Due to the larger spherical structure, the internal reaction zone will be protected, resulting in a reduction in its specific surface area, resulting in the inability to maximize its adsorption capacity. Therefore, researchers are committed to transforming biosynthesized Schneideria minerals to improve adsorption activity and adsorption capacity. The measures taken mainly focus on controlling environmental factors such as pH, temperature, formation time and culture medium. However, these measures cannot effectively modulate the structure of Schneideria minerals. At the same time, the adsorbent is greatly affected by pH when treating (loid) metals in wastewater. The adsorption effect is worse under acidic conditions than in neutral environments, and the same is true for Schmitten minerals. Therefore, the present invention wants to improve the performance of biosynthesis of Schretzite minerals in a gentle and non-biologically lethal way by adding crystal seeds (which provide more surface sites for the formation of Schretzite minerals).
一般来说，晶种需要提供足够的表面（即生长位点）用于生长，因此常采用较小的晶体颗粒作为晶种，而非常少量的大晶体在晶化过程中往往较难起到显著的效果。根据施氏矿物合成的条件，所需晶种还需要酸性条件下稳定，比表面积大、颗粒粒度均匀、适宜，性价比高，具有固定的内部结构，和施氏矿物结构和成分类似，对 Fe(III) 和 SO 4 2- 有一定的吸附能力。因此，我们首先考虑到普遍存在于自然环境中铁氧化物，主要包括铁的氧化物与铁的氢氧化合物 ( 也称之为羟基氧化铁， FeOOH ) 。其中 FeOOH 具有较大的比表面积、较稳定的理化性质和特殊的结构特征等优点，对环境中的污染物的治理起着重要的净化作用。目前关注的 FeOOH 主要为针铁矿 (α-FeOOH) 、四方纤铁矿 (β-FeOOH) 、纤铁矿 (γ-FeOOH) 。其中，四方纤铁矿 (β-FeOOH) 是在富含氯离子和铁环境中形成的纳米颗粒，在富含氯的地带和酸性矿山废水中也曾发现它的存在。 β-FeOOH 具有与施氏矿物类似的隧道结构结，结构中包含着共用边的双链八面体，共边八面体与相邻的链共用角，形成平行于 c 轴的通道。 β-FeOOH 为纳米颗粒，具有无毒性、低成本、在酸性条件下具有良好的稳定性等优点。因此，在 β-FeOOH 特定官能团（大量的羟基）的诱导作用下，无机物可能会迁移、富集、转化并形成次生矿物。形成的施氏矿物的性质将随着 β-FeOOH 的添加剂量而变化。在此基础上，本发明***研究了 β-FeOOH 作为晶种介导生物合成纳米级施氏矿物的可行性。我们的目的是在生物合成***中调节施氏矿物的形态、结构和表面性质，增加官能团的数量，提高其对重金属的反应活性。该发明为生物合成的高性能吸附剂做出了贡献，对深化施氏矿物生物合成的认识具有重要意义。 Generally speaking, seed crystals need to provide enough surface (i.e. growth sites) for growth, so smaller crystal particles are often used as seeds, while a very small amount of large crystals are often difficult to play a significant role in the crystallization process. Effect. According to the conditions for the synthesis of Schretzite minerals, the required crystal seeds also need to be stable under acidic conditions, have a large specific surface area, uniform and suitable particle size, high cost performance, and have a fixed internal structure, similar to the structure and composition of Schretzite minerals. For Fe ( III) and SO 4 2- have certain adsorption capacity. Therefore, we first consider that iron oxides are commonly found in the natural environment, mainly including iron oxides and iron hydroxides ( also called iron oxyhydroxide, FeOOH ) . Among them, FeOOH has the advantages of large specific surface area, relatively stable physical and chemical properties and special structural characteristics, and plays an important purification role in the treatment of pollutants in the environment. The FeOOH currently of concern is mainly goethite (α-FeOOH) , tetragonal lepidocrocite (β-FeOOH) , and lepidocrocite (γ-FeOOH) . Among them, tetragonal lepidocrocite (β-FeOOH) is a nanoparticle formed in an environment rich in chloride ions and iron. It has also been found in chlorine-rich areas and acidic mine wastewater. β-FeOOH has a tunnel structure similar to that of Schmitten minerals. The structure contains double-chain octahedrons that share edges. The edge-sharing octahedrons share angles with adjacent chains, forming a channel parallel to the c- axis . β-FeOOH is a nanoparticle with the advantages of non-toxicity, low cost, and good stability under acidic conditions. Therefore, under the induction of β-FeOOH specific functional groups (a large number of hydroxyl groups), inorganic substances may migrate, enrich, transform and form secondary minerals. The properties of the formed Schnitz minerals will change with the amount of β-FeOOH added. On this basis, the present invention systematically studied the feasibility of using β-FeOOH as a crystal seed to mediate the biosynthesis of nanoscale Schretzite minerals. Our purpose is to adjust the morphology, structure and surface properties of Schmitten minerals in biosynthetic systems, increase the number of functional groups, and improve their reactivity towards heavy metals. This invention has contributed to the development of high-performance adsorbents for biosynthesis and is of great significance to deepening the understanding of biosynthesis of Schneiderii minerals .
技术解决方案Technical solutions
针对现有技术中，生物合成施氏矿物产率不高、周期长的问题，本发明的目的之一是提供一种高产率的施氏矿物的合成方法；且可以缩短生物合成施氏矿物的周期。本发明目的之二是为了增强施氏矿物去除酸性废水中五价砷和六价铬的性能。利用本发明制备的施氏矿物产量高，合成周期短，成本低廉，对水体中As(V)和Cr(VI)污染治理效果好，可应用于采矿等工业废水的治理。In view of the problems of low yield and long cycle of biosynthesizing Schreiberite minerals in the prior art, one of the purposes of the present invention is to provide a synthesis method of Schrezfeldt minerals with high yield; and can shorten the time of biosynthesizing Schretzite minerals. cycle. The second purpose of the present invention is to enhance the performance of Shi's mineral in removing pentavalent arsenic and hexavalent chromium in acidic wastewater. The Shiite mineral prepared by the invention has high yield, short synthesis cycle, low cost, good effect on As(V) and Cr(VI) pollution control in water bodies, and can be applied to the treatment of industrial wastewater such as mining.
本发明的目的通过以下技术方案实现：The object of the present invention is achieved through the following technical solutions:
一种添加外源晶种介导施氏矿物的生物合成方法，包括以下步骤：A method for adding exogenous crystal seeds to mediate the biosynthesis of Strychite minerals, including the following steps:
（1）在硫酸亚铁溶液中加入β-FeOOH纳米晶种溶液，然后加入A. ferrooxidans休止细胞悬浮液，得混合液；(1) Add β-FeOOH nanocrystal seed solution to the ferrous sulfate solution, and then add A. ferrooxidans resting cell suspension to obtain a mixed solution;
（2）将步骤（1）的混合液置于25~30℃培养42-72h，培养结束后；矿物沉淀洗涤、冷冻干燥、过筛，得添加外源晶种介导合成的施氏矿物。(2) Cultivate the mixture in step (1) at 25~30°C for 42-72 hours. After the culture is completed, the mineral precipitate is washed, freeze-dried, and sieved to add exogenous seed crystal-mediated synthesis of Schretz's mineral.
优选的，步骤（1）所述A. ferrooxidans休止细胞悬浮液中A. ferrooxidans的密度为1×10 8 ~3×10 8 cells/ml；更优选的密度为1×10 8 cells/ml。 Preferably, the density of A. ferrooxidans in the A. ferrooxidans resting cell suspension described in step (1) is 1×10 8 ~3×10 8 cells/ml; a more preferred density is 1×10 8 cells/ml.
优选的，步骤（1）所述β-FeOOH纳米晶种溶液的浓度为0.001~0.1 g/mL。更优选的浓度为0.01 g/mL。Preferably, the concentration of the β-FeOOH nanocrystal seed solution in step (1) is 0.001~0.1 g/mL. A more preferred concentration is 0.01 g/mL.
优选的，步骤（1）所述混合液中硫酸亚铁的浓度为20~160 mMol/L；更优选的浓度为80 mMol/L；Preferably, the concentration of ferrous sulfate in the mixed solution described in step (1) is 20~160 mmol/L; a more preferred concentration is 80 mmol/L;
优选的，步骤（1）所述β-FeOOH纳米晶种溶液和混合液的体积比为2~128：:1000；更优选的体积比为（2、4、8、16、32、64、128）：1000；Preferably, the volume ratio of the β-FeOOH nanocrystal seed solution and the mixed solution in step (1) is 2~128::1000; the more preferred volume ratio is (2, 4, 8, 16, 32, 64, 128 ): 1000;
优选的，步骤（1）所述A. ferrooxidans休止细胞悬浮液和混合液的体积比为1:50~100。更优选的体积比为1:100。Preferably, the volume ratio of the A. ferrooxidans resting cell suspension and the mixed solution in step (1) is 1:50~100. A more preferred volume ratio is 1:100.
优选的，步骤（2）所述培养在150~200 r/min摇床中培养；Preferably, the culture in step (2) is performed at 150 to 200 Culture in shaker at r/min;
优选的，步骤（2） 所述洗涤为去离子水洗涤；所述冷冻干燥的温度为-30 ~ -45℃，时间为12~36 h；所述过筛为过100~200目筛。Preferably, the washing in step (2) is deionized water washing; the freeze-drying temperature is -30~-45°C and the time is 12~36 h; and the sieving is passing through a 100~200 mesh sieve.
优选的，步骤（1）所述β-FeOOH纳米晶种溶液的制备方法包括以下步骤：Preferably, the preparation method of the β-FeOOH nanocrystal seed solution in step (1) includes the following steps:
氯化铁加入无水乙醇溶解，再加入去离子水混合拌匀得反应液，80~100 ℃反应36~54 h；反应结束后，离心、洗涤、冷冻干燥得到β-FeOOH纳米晶种；将所得的β-FeOOH纳米晶种加水超声分散得到β-FeOOH纳米晶种溶液。Dissolve ferric chloride in absolute ethanol, then add deionized water and mix well to obtain a reaction solution, react at 80~100°C for 36~54 hours; after the reaction is completed, centrifuge, wash, and freeze-dry to obtain β-FeOOH nanocrystal seeds; The obtained β-FeOOH nanocrystal seeds are added with water and ultrasonically dispersed to obtain a β-FeOOH nanocrystal seed solution.
更优选的，所述氯化铁为FeCl 3·6H 2O；所述反应液中氯化铁的浓度为0.2~0.4 Mol/L；所述无水乙醇和去离子水的体积比为1：1-1.5； More preferably, the ferric chloride is FeCl 3 ·6H 2 O; the concentration of ferric chloride in the reaction solution is 0.2~0.4 Mol/L; the volume ratio of the absolute ethanol and deionized water is 1: 1-1.5;
更优选的，所述洗涤为无水乙醇和去离子水洗涤至中性；所述冷冻干燥的时间为12~36h；More preferably, the washing is with absolute ethanol and deionized water until neutral; the freeze-drying time is 12 to 36 hours;
更优选的，所述超声分散的时间为30~45分钟。More preferably, the ultrasonic dispersion time is 30 to 45 minutes.
优选的，所述A. ferrooxidans休止细胞悬浮液的制备方法包括以下步骤：Preferably, the preparation method of the A. ferrooxidans resting cell suspension includes the following steps:
将9K培养基高温高压灭菌，接种A. ferrooxidans细菌，加入硫酸亚铁，调节pH，培养2~3天；过滤除去铁沉淀物，滤液离心后收集菌体，洗涤、悬浮得到A. ferrooxidans休止细胞悬浮液。Sterilize the 9K culture medium at high temperature and high pressure, inoculate A. ferrooxidans bacteria, add ferrous sulfate, adjust the pH, and culture for 2 to 3 days; filter to remove iron precipitates, collect the filtrate after centrifugation, wash and suspend to obtain A. ferrooxidans rest cell suspension.
更优选的，所述离心的温度为4~7℃，离心力为10000~12000 g，时间为8~10分钟；More preferably, the centrifugal temperature is 4~7°C, and the centrifugal force is 10000~12000 g, time is 8~10 minutes;
更优选的，所述悬浮后的体积为为培养基的1/50~1/100。More preferably, the volume after suspension is 1/50~1/100 of the culture medium.
更优选的，所述调节pH为用H 2SO 4调节pH至2-3。 More preferably, the pH adjustment is to use H 2 SO 4 to adjust the pH to 2-3.
上述的生物合成方法合成得到的添加外源晶种介导合成的施氏矿物。The above-mentioned biosynthetic method is used to synthesize Schmitz minerals that are mediated by adding exogenous crystal seeds.
上述的添加外源晶种介导合成的施氏矿物在去除水体中As(V)和Cr(VI)污染中的应用。The application of the above-mentioned addition of exogenous seed crystals to mediate the synthesis of Schmitten minerals in the removal of As(V) and Cr(VI) pollution in water bodies.
有益效果beneficial effects
与现有技术相比，本发明具有以下优点：Compared with the prior art, the present invention has the following advantages:
（1）本发明“晶种法”能直接提供晶核，给施氏矿物的生长提供晶体生长的位点，从而大大缩短诱导期和成核期。因此，本发明能缩短微生物成矿的周期（由原来的66h降到42h）。未添加晶种的对比例三价铁水解成矿在66 h结束，而本发明添加晶种在42 h便沉淀结束，缩短了微生物成矿周期。(1) The "crystal seeding method" of the present invention can directly provide crystal nuclei and provide crystal growth sites for the growth of Schmitten minerals, thus greatly shortening the induction period and nucleation period. Therefore, the present invention can shorten the microbial mineralization cycle (from the original 66h to 42h). The hydrolysis mineralization of ferric iron in the comparative example without added seed crystals ended in 66 hours, while the precipitation of the present invention with added crystal seeds ended in 42 hours, shortening the microbial mineralization cycle.
（2）本发明合成的施氏矿物产量高，且明显高于不添加晶种合成的产量。本发明合成矿物总产量比不添加晶种的对比例高8.0% ~96.7%。(2) The yield of Schmitten mineral synthesized by the present invention is high, and is significantly higher than the yield synthesized without adding crystal seeds. The total output of synthetic minerals of the present invention is 8.0% to 96.7% higher than the comparative example without adding crystal seeds.
（3）本发明制备的施氏矿物对水体中As(V)和Cr(VI)去除效果更好，这为治理富含As(V)和Cr(VI)的污染废水提供了一种有效途径。(3) The Shiite mineral prepared by the present invention has a better removal effect on As(V) and Cr(VI) in water, which provides an effective way to treat contaminated wastewater rich in As(V) and Cr(VI). .
（4）本发明以铁盐为原材料，原材料简单易得，且微生物成矿是一种有效、可持续、低成本的合成方法，工艺流程简单、操作便捷、生产成本低廉。(4) The present invention uses iron salt as raw material, which is simple and easy to obtain, and microbial mineralization is an effective, sustainable and low-cost synthesis method with simple process flow, convenient operation and low production cost.
附图说明Description of the drawings
图1为本发明实施例1～7和对比例制备的施氏矿物及β-FeOOH纳米颗粒的特征X-射线衍射图(XRD)。Figure 1 is the characteristic X-ray diffraction pattern (XRD) of the Schmitten minerals and β-FeOOH nanoparticles prepared in Examples 1 to 7 and Comparative Examples of the present invention.
图2为本发明实施例1～7和对比例制备的施氏矿物及β-FeOOH纳米颗粒的扫描电镜图（SEM）。Figure 2 is a scanning electron microscope (SEM) image of Schmitten minerals and β-FeOOH nanoparticles prepared in Examples 1 to 7 and Comparative Examples of the present invention.
图3为本发明实施例1～7和对比例制备的施氏矿物及β-FeOOH纳米颗粒的红外光谱图（FTIR）。Figure 3 is an infrared spectrum (FTIR) of the Schmitten minerals and β-FeOOH nanoparticles prepared in Examples 1 to 7 and Comparative Examples of the present invention.
图4为本发明实施例1～7和对比例制备的施氏矿物的亚铁氧化速率图。Figure 4 is a graph showing the ferrous iron oxidation rate of the Strychite minerals prepared in Examples 1 to 7 and Comparative Examples of the present invention.
图5为本发明实施例1～7和对比例制备的施氏矿物的三价铁成矿图。Figure 5 is a diagram of ferric iron mineralization of Schmitten minerals prepared in Examples 1 to 7 and Comparative Examples of the present invention.
图6为本发明实施例1～7和对比例制备的施氏矿物的总产量和净产量柱状图。Figure 6 is a histogram showing the total production and net production of Schmitten minerals prepared in Examples 1 to 7 and Comparative Examples of the present invention.
图7为本发明实施例1～7和对比例制备的施氏矿物及β-FeOOH纳米颗粒在不同As(V)浓度去除As(V)的曲线（a.去除率；b.吸附容量）。Figure 7 shows the As(V) removal curves (a. Removal rate; b. Adsorption capacity) of Strychite minerals and β-FeOOH nanoparticles prepared in Examples 1 to 7 of the present invention and β-FeOOH nanoparticles at different As(V) concentrations.
图8为本发明实施例1～7和对比例制备的施氏矿物及β-FeOOH纳米颗粒在不同Cr(VI)浓度去除Cr(VI)的曲线（a.去除率；b.吸附容量）。Figure 8 shows the Cr(VI) removal curves (a. removal rate; b. adsorption capacity) of Strychite minerals and β-FeOOH nanoparticles prepared in Examples 1 to 7 of the present invention and β-FeOOH nanoparticles at different Cr(VI) concentrations.
图9为本发明实施例3、6和对比例制备的施氏矿物及β-FeOOH纳米颗粒在不同pH下去除As(V)的曲线（a.去除率；b.吸附容量）。Figure 9 shows the As(V) removal curves (a. removal rate; b. adsorption capacity) of Strychite minerals and β-FeOOH nanoparticles prepared in Examples 3 and 6 of the present invention and β-FeOOH nanoparticles at different pH values.
图10为本发明实施例3、6和对比例制备的施氏矿物及β-FeOOH纳米颗粒在不同pH下去除Cr(VI)的曲线（a.去除率；b.吸附容量）。Figure 10 shows the Cr(VI) removal curves (a. removal rate; b. adsorption capacity) of Strychite minerals and β-FeOOH nanoparticles prepared in Examples 3 and 6 of the present invention and β-FeOOH nanoparticles at different pH.
图11为本发明实施例3、6和对比例制备的施氏矿物的吸附动力学曲线{a.As(V)；b.Cr(VI)}。Figure 11 is the adsorption kinetic curve {a.As(V); b.Cr(VI)} of the Strychite mineral prepared in Examples 3, 6 and Comparative Examples of the present invention.
本发明的实施方式Embodiments of the invention
以下结合附图和实例对本发明的具体实施作进一步说明，但本发明的实施和保护不限于此。需指出的是，以下若有未特别详细说明之过程，均是本领域技术人员可参照现有技术实现或理解的。所用试剂或仪器未注明生产厂商者，视为可以通过市售购买得到的常规产品。The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be pointed out that any process that is not specifically described in detail below can be implemented or understood by those skilled in the art with reference to the existing technology. If the manufacturer of the reagents or instruments used is not indicated, they are regarded as conventional products that can be purchased commercially.
一种添加外源晶种介导施氏矿物的生物合成方法，包括以下步骤：A method for adding exogenous crystal seeds to mediate the biosynthesis of Strychite minerals, including the following steps:
（1）β-FeOOH纳米晶种溶液的制备：(1) Preparation of β-FeOOH nanocrystal seed solution:
称取一定量的FeCl 3·6 H 2O，加入无水乙醇溶解，再缓慢匀速加入一定量的去离子水。混合拌匀后移入反应釜中，设定反应温度在90℃， 反应45 h。 反应结束后，用无水乙醇和去离子水洗涤几次离心，将沉淀清洗至呈中性后在冷冻干燥24 h得到β-FeOOH纳米颗粒。将所得的纳米晶种β-FeOOH，配置成 0.01g/mL的水溶液，超声30分钟后使β-FeOOH纳米颗粒在溶液中分散均匀，作为合成施氏矿物的晶种。 Weigh a certain amount of FeCl 3 ·6 H 2 O, add absolute ethanol to dissolve it, and then add a certain amount of deionized water slowly and uniformly. Mix well and then move it into the reaction kettle, set the reaction temperature at 90°C, and react for 45 hours. After the reaction, wash with absolute ethanol and deionized water several times and centrifuge. The precipitate is washed until neutral and freeze-dried for 24 h to obtain β-FeOOH nanoparticles. The obtained nanocrystalline seed β-FeOOH was prepared into an aqueous solution of 0.01g/mL. After ultrasonic for 30 minutes, the β-FeOOH nanoparticles were evenly dispersed in the solution as seed crystals for synthesizing Schmitten mineral.
所述步骤(1)中的FeCl 3·6 H 2O的浓度为0.2Mol/L，无水乙醇和去离子水比例为1:1；所得的β-FeOOH结晶度好，颗粒均匀，为长约60nm，宽30nm的纺锤形纳米颗粒。 The concentration of FeCl 3 ·6 H 2 O in the step (1) is 0.2Mol/L, and the ratio of absolute ethanol and deionized water is 1:1; the resulting β-FeOOH has good crystallinity, uniform particles, and long Spindle-shaped nanoparticles about 60nm in diameter and 30nm in width.
（2）A. ferrooxidans休止细胞悬浮液的制备：(2) Preparation of A. ferrooxidans resting cell suspension:
A. ferrooxidans菌株是从我国广东省的一座硫铁矿山的酸性矿山废水中分离纯化得到（由中国典型培养物保藏中心保藏，简称CCTCC，保藏号为：CCTCC NO： M2013102）。采用9K培养基对该菌株进行培养。先将9K培养基高温高压灭菌，然后将A. ferrooxidans菌接种在灭菌后的9K培养基中，再加入FeSO 4·7H 2O使其浓度约为44.2 g/L，用1 mol/L H 2SO 4调节pH至2.5。将接种好的培养液置于30℃摇床中180 r/min振荡培养，对数生长期后停止培养（约2~3天）。随后将培养液经定性滤纸过滤以除去铁沉淀物，滤液在4℃、10000 g下离心10分钟，收集菌体。菌体用H 2SO 4溶液（pH~2.5）洗涤3次，再用H 2SO 4溶液（pH~2.5）悬浮。1 L培养液大约收集20 ml细菌悬浮液，得到浓缩菌液（50倍）。其中A. ferrooxidans密度约为1×10 8 cells/ml。 The A. ferrooxidans strain was isolated and purified from the acid mine wastewater of a pyrite mine in Guangdong Province, my country (preserved by the China Type Culture Collection Center, referred to as CCTCC, the preservation number is: CCTCC NO: M2013102). This strain was cultured using 9K medium. First, sterilize the 9K culture medium under high temperature and high pressure, then inoculate A. ferrooxidans bacteria into the sterilized 9K culture medium, then add FeSO 4 ·7H 2 O to make the concentration approximately 44.2 g/L, and use 1 mol/LH 2 SO 4 Adjust pH to 2.5. Place the inoculated culture medium in a 30°C shaker and culture it with shaking at 180 r/min. Stop the culture after the logarithmic growth phase (about 2 to 3 days). The culture solution was then filtered through qualitative filter paper to remove iron precipitates, and the filtrate was centrifuged at 4°C and 10,000 g for 10 minutes to collect the bacterial cells. The bacterial cells were washed three times with H 2 SO 4 solution (pH ~ 2.5), and then suspended in H 2 SO 4 solution (pH ~ 2.5). Collect approximately 20 ml of bacterial suspension from 1 L of culture solution to obtain a concentrated bacterial solution (50 times). The density of A. ferrooxidans is approximately 1×10 8 cells/ml.
（3）施氏矿物的制备：(3) Preparation of Shishi minerals:
在1 L三角瓶中加入FeSO 4·7H 2O制备施氏矿物，加入一定量步骤（1）所得的β-FeOOH纳米颗粒溶液，然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL（Fe 2+浓度达到80 mMol/L）；再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，去离子水洗涤后-45℃冷冻干燥24h后过100目筛即得晶种介导合成的施氏矿物。 Add FeSO 4 ·7H 2 O to a 1 L Erlenmeyer flask to prepare Schmitten mineral, add a certain amount of β-FeOOH nanoparticle solution obtained in step (1), and then add 5 ml of A. ferrooxidans prepared in step (2). Stop the cell suspension and add an appropriate amount of deionized water to make the total system 500mL (Fe 2+ concentration reaches 80 mMol/L); then place the above mixture in a shaker at 30°C and 180 r/min for 3 days. After the culture is completed, wash with deionized water, freeze-dry at -45°C for 24 hours, and then pass through a 100-mesh sieve to obtain the seed-mediated synthesis of Schretz's mineral.
所述步骤(3)中加入体系的β-FeOOH纳米颗粒溶液的体积为0、1、2、4、8、16、32、64 mL。所合成的施氏矿物分别记作对比例、实施例1、实施例2、实施例3、实施例4、实施例5、实施例6、实施例7，对比例作为空白对照组。The volume of the β-FeOOH nanoparticle solution added to the system in step (3) is 0, 1, 2, 4, 8, 16, 32, 64 mL. The synthesized Schmittenberg minerals were respectively recorded as Comparative Example, Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, and Example 7, and the Comparative Example was used as a blank control group.
实施例Example 11
在1 L三角瓶中加入11.12 g FeSO 4·7H 2O制备施氏矿物，使Fe 2+浓度达到80 mMol/L；再加入1mL步骤（1）所得的β-FeOOH纳米浓缩液，然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL，再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，将收集的矿物用去离子水洗涤、离心干燥后得到1.63g矿物。 Add 11.12 g FeSO 4 ·7H 2 O into a 1 L Erlenmeyer flask to prepare Schmitten mineral, so that the Fe 2+ concentration reaches 80 mMol/L; then add 1 mL of the β-FeOOH nanoconcentrate obtained in step (1), and then add 5 ml of the A. ferrooxidans resting cell suspension prepared in step (2), add an appropriate amount of deionized water to make the total system 500 mL, and then place the above mixture in a shaker at 30°C and 180 r/min for 3 days. After the culture, the collected minerals were washed with deionized water, centrifuged and dried to obtain 1.63g of minerals.
实施例Example 22
在1 L三角瓶中加入11.12 g FeSO 4·7H 2O制备施氏矿物，使Fe 2+浓度达到80 mMol/L；再加入2mL步骤（1）所得的β-FeOOH纳米浓缩液，然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL，再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，将收集的矿物用去离子水洗涤、离心干燥后得到1.68g矿物。 Add 11.12 g FeSO 4 ·7H 2 O to a 1 L Erlenmeyer flask to prepare Schmitten mineral, so that the Fe 2+ concentration reaches 80 mMol/L; then add 2 mL of the β-FeOOH nanoconcentrate obtained in step (1), and then add 5 ml of the A. ferrooxidans resting cell suspension prepared in step (2), add an appropriate amount of deionized water to make the total system 500 mL, and then place the above mixture in a shaker at 30°C and 180 r/min for 3 days. After the culture, the collected minerals were washed with deionized water, centrifuged and dried to obtain 1.68g of minerals.
实施例Example 33
在1 L三角瓶中加入11.12 g FeSO 4·7H 2O制备施氏矿物，使Fe 2+浓度达到80 mMol/L；再加入4mL步骤（1）所得的β-FeOOH纳米浓缩液，然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL，再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，将收集的矿物用去离子水洗涤、离心干燥后得到1.75g矿物。 Add 11.12 g FeSO 4 ·7H 2 O into a 1 L Erlenmeyer flask to prepare Schmitten mineral, so that the Fe 2+ concentration reaches 80 mMol/L; then add 4 mL of the β-FeOOH nanoconcentrate obtained in step (1), and then add 5 ml of the A. ferrooxidans resting cell suspension prepared in step (2), add an appropriate amount of deionized water to make the total system 500 mL, and then place the above mixture in a shaker at 30°C and 180 r/min for 3 days. After the culture, the collected minerals were washed with deionized water, centrifuged and dried to obtain 1.75g of minerals.
实施例Example 44
在1 L三角瓶中加入11.12 g FeSO 4·7H 2O制备施氏矿物，使Fe 2+浓度达到80 mMol/L；再加入8 mL步骤（1）所得的β-FeOOH纳米浓缩液，然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL，再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，将收集的矿物用去离子水洗涤、离心干燥后得到1.81g矿物。 Add 11.12 g FeSO 4 ·7H 2 O into a 1 L Erlenmeyer flask to prepare Schmitten mineral, so that the Fe 2+ concentration reaches 80 mMol/L; then add 8 mL of the β-FeOOH nanoconcentrate obtained in step (1), and then add 5 ml of the A. ferrooxidans resting cell suspension prepared in step (2), add an appropriate amount of deionized water to make the total system 500 mL, and then place the above mixture in a shaker at 30°C and 180 r/min for 3 days. . After the culture, the collected minerals were washed with deionized water, centrifuged and dried to obtain 1.81g of minerals.
实施例Example 55
在1 L三角瓶中加入11.12 g FeSO 4·7H 2O制备施氏矿物，使Fe 2+浓度达到80 mMol/L；再加入16 mL步骤（1）所得的β-FeOOH纳米浓缩液，然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL，再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，将收集的矿物用去离子水洗涤、离心干燥后得到2.01g矿物。 Add 11.12 g FeSO 4 ·7H 2 O to a 1 L Erlenmeyer flask to prepare Schmitten mineral, so that the Fe 2+ concentration reaches 80 mMol/L; then add 16 mL of the β-FeOOH nanoconcentrate obtained in step (1), and then add 5 ml of the A. ferrooxidans resting cell suspension prepared in step (2), add an appropriate amount of deionized water to make the total system 500 mL, and then place the above mixture in a shaker at 30°C and 180 r/min for 3 days. . After the culture, the collected minerals were washed with deionized water, centrifuged and dried to obtain 2.01g of minerals.
实施例Example 66
在1 L三角瓶中加入11.12 g FeSO 4·7H 2O制备施氏矿物，使Fe 2+浓度达到80 mMol/L；再加入32 mL步骤（1）所得的β-FeOOH纳米浓缩液，然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL，再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，将收集的矿物用去离子水洗涤、离心干燥后得到2.39g矿物。 Add 11.12 g FeSO 4 ·7H 2 O to a 1 L Erlenmeyer flask to prepare Schmitt's mineral, so that the Fe 2+ concentration reaches 80 mMol/L; then add 32 mL of the β-FeOOH nanoconcentrate obtained in step (1), and then add 5 ml of the A. ferrooxidans resting cell suspension prepared in step (2), add an appropriate amount of deionized water to make the total system 500 mL, and then place the above mixture in a shaker at 30°C and 180 r/min for 3 days. . After the culture, the collected minerals were washed with deionized water, centrifuged and dried to obtain 2.39g of minerals.
实施例Example 77
在1 L三角瓶中加入11.12 g FeSO 4·7H 2O制备施氏矿物，使Fe 2+浓度达到80 mMol/L；再加入64 mL步骤（1）所得的β-FeOOH纳米浓缩液，然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL，再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，将收集的矿物用去离子水洗涤、离心干燥后得到2.97g矿物。 Add 11.12 g FeSO 4 ·7H 2 O to a 1 L Erlenmeyer flask to prepare Schmitten mineral, so that the Fe 2+ concentration reaches 80 mMol/L; then add 64 mL of the β-FeOOH nanoconcentrate obtained in step (1), and then add 5 ml of the A. ferrooxidans resting cell suspension prepared in step (2), add an appropriate amount of deionized water to make the total system 500 mL, and then place the above mixture in a shaker at 30°C and 180 r/min for 3 days. . After the culture, the collected minerals were washed with deionized water, centrifuged and dried to obtain 2.97g of minerals.
对比例Comparative ratio
在1 L三角瓶中加入11.12 g FeSO 4·7H 2O制备施氏矿物，使Fe 2+浓度达到80 mMol/L；然后加入5 ml步骤（2）中已制备好的A. ferrooxidans休止细胞悬浮液，加入适量去离子水使得总体系为500mL，再将上述混合液置于30℃、180 r/min摇床中培养3天。培养结束后，将收集的矿物用去离子水洗涤、离心干燥后得到1.51g矿物。 Add 11.12 g FeSO 4 ·7H 2 O to a 1 L Erlenmeyer flask to prepare Schmitt's mineral so that the Fe 2+ concentration reaches 80 mMol/L; then add 5 ml of the A. ferrooxidans resting cell suspension prepared in step (2) solution, add an appropriate amount of deionized water to make the total system 500 mL, and then place the above mixed solution in a shaker at 30°C and 180 r/min for 3 days. After the culture, the collected minerals were washed with deionized water, centrifuged and dried to obtain 1.51g of minerals.
物相鉴定Physical phase identification
对比制备的矿物XRD图谱（图1）和SEM扫描电镜图（图2），合成的晶种（β-FeOOH）特征峰明显，晶型好，纯度高，为长60 nm、宽30 nm的纺锤状颗粒。从图1可知本发明制备的施氏矿物的特征峰与已有报道的矿物特征峰相同，确定为施氏矿物，且实施例的比表面积（BET）比对比例更大。由图1和图2可知：添加晶种（β-FeOOH）所制备的施氏矿物比对比例（不使用晶种合成的施氏矿物）颗粒更分散，表面毛刺更多，比表面积更大，表明本发明通过晶种诱导可以增加施氏矿的吸附位点，从而可以增加施氏矿物对重金属的吸附量。Comparing the XRD pattern of the prepared mineral (Figure 1) and the SEM scanning electron microscope picture (Figure 2), the synthesized seed crystal (β-FeOOH) has obvious characteristic peaks, good crystal form, and high purity. It is a spindle with a length of 60 nm and a width of 30 nm. shaped particles. It can be seen from Figure 1 that the characteristic peaks of the Schretzite mineral prepared by the present invention are the same as those of previously reported minerals, and are determined to be Schretzite minerals, and the specific surface area (BET) of the example is larger than that of the comparative example. It can be seen from Figures 1 and 2 that the particles of the Schretzite mineral prepared by adding seed crystals (β-FeOOH) are more dispersed, have more surface burrs, and have a larger specific surface area than the comparative example (the Schretzite mineral synthesized without using crystal seeds). It shows that the present invention can increase the adsorption sites of Schretzite through crystal seed induction, thereby increasing the adsorption amount of heavy metals by Schretzite.
实施例和对比例的红外光谱图（FTIR）如图3所示。由图3可知1647 cm -1由水分子变形所致，1078、950、688 cm -1应分别归属于施氏矿物SO 4 2-的v3、v1、 v4衍射峰。红外光谱分析结果进一步证明，本发明制备的矿物为施氏矿物。不同是 -OH的红外光谱图上的衍射峰，对比例的-OH衍射峰位置在3159 cm -1处，随着晶种添加量的增加，实施例1到实施例7的-OH伸缩振动吸收峰的位置由3159 cm -1处向3300cm -1处偏移，且-OH衍射峰的强度逐渐变大，说明晶种诱导施氏矿物可能成功的引入了更多的-OH，利于吸附重金属。铁羟基矿物表面可能有三种含量不相等的表面羟基官能团，不同表面羟基官能团根据氧与铁的配位不同命名为A、B、C型羟基，每种类型的羟基具有明显不同的酸度和对吸附物的反应活性。A型羟基被认为是最活泼的，B型和C型羟基被认为是惰性的，基本不参与反应。 The infrared spectra (FTIR) of the examples and comparative examples are shown in Figure 3. From Figure 3, it can be seen that 1647 cm -1 is caused by the deformation of water molecules, and 1078, 950, and 688 cm -1 should be attributed to the v3, v1, and v4 diffraction peaks of Schmitten mineral SO 4 2- respectively. The infrared spectrum analysis results further prove that the mineral prepared by the present invention is Schmitten mineral. The difference is the diffraction peak on the infrared spectrum of -OH. The -OH diffraction peak position of the comparative example is at 3159 cm -1 . As the amount of seed crystal added increases, the stretching vibration absorption of -OH from Example 1 to Example 7 The position of the peak shifts from 3159 cm -1 to 3300 cm -1 , and the intensity of the -OH diffraction peak gradually becomes larger, indicating that the seed-induced Schmitten mineral may have successfully introduced more -OH, which is beneficial to the adsorption of heavy metals. There may be three types of surface hydroxyl functional groups with unequal content on the surface of iron hydroxyl minerals. Different surface hydroxyl functional groups are named A, B, and C-type hydroxyl groups according to the coordination between oxygen and iron. Each type of hydroxyl group has significantly different acidity and adsorption properties. reactivity of the substance. Type A hydroxyl groups are considered to be the most reactive, while type B and C hydroxyl groups are considered inert and basically do not participate in the reaction.
合矿周期和产量Combined ore cycle and output
从图4可以看出，添加晶种诱导施氏矿物合成能加快Acidithiobacillus. ferrooxidans氧化亚铁速率，对照例二价铁在66 h氧化完全 ，而实施例几乎在42h左右氧化完全。It can be seen from Figure 4 that adding crystal seeds to induce the synthesis of Schmitten minerals can accelerate the oxidation rate of ferrous iron by Acidithiobacillus. ferrooxidans. The ferrous iron in the control example was completely oxidized in 66 hours, while the oxidation in the example was almost complete in about 42 hours.
从图5可以看出，对照例三价铁在66 h水解成矿结束 ，而实施例几乎在42 h三价铁便沉淀结束，这大大缩短了微生物合成施氏矿物的周期，在一定程度上克服了微生物成矿周期长的缺点；此外，添加晶种能提高对三价铁水解成矿的比例（约3%~5%）。As can be seen from Figure 5, the hydrolysis of ferric iron in the control example and mineralization ended at 66 hours, while the precipitation of ferric iron in the example almost ended at 42 hours, which greatly shortened the cycle of microbial synthesis of Schretz minerals, to a certain extent. It overcomes the shortcoming of long microbial mineralization cycle; in addition, adding seed crystals can increase the proportion of ferric iron hydrolysis and mineralization (about 3% to 5%).
从图6可以看出，添加晶种能增加施氏矿物成产量，实施例1到实施例7矿物总产量比对比例分别高8.0% 、11.3%、15.9%、19.9%、33.1%、58.3%、96.7%。实施例1到实施例7矿物净产量比对比例分别高7.3% 、10%、13.2%、14.6%、22.5%、37.1%、54.3%。这里净产量指的是扣除添加晶种重量后的施氏矿物产量，因为晶种可能未被全部利用且为纳米颗粒，在洗涤矿物中，纳米颗粒已被洗掉，因此这里是最低净产量。因此，本发明是一种高产量的施氏矿物合成方法。It can be seen from Figure 6 that adding seed crystals can increase the output of Schmitten minerals. The total mineral output of Examples 1 to 7 is 8.0%, 11.3%, 15.9%, 19.9%, 33.1%, and 58.3% higher than the comparative example respectively. ,96.7%. The net mineral yields of Examples 1 to 7 are respectively 7.3%, 10%, 13.2%, 14.6%, 22.5%, 37.1%, and 54.3% higher than those of the comparative example. The net production here refers to the production of Schmitten minerals after deducting the weight of added seed crystals, because the seed crystals may not be fully utilized and are nanoparticles. In the washed minerals, the nanoparticles have been washed away, so this is the minimum net production. Therefore, the present invention is a high-yield method for synthesizing Schmitten minerals.
施氏矿物在去除水体中五价砷和六价铬污染中的应用Application of Shishi minerals in removing pentavalent arsenic and hexavalent chromium pollution from water bodies
吸附批实验：Adsorption batch experiment:
实施例1到实施例7合成的施氏矿物、对比例和β-FeOOH吸附As(V)和Cr(VI)的批实验反应体系是在50 mL离心管内加入30 mL含指定浓度As(V)和Cr(VI)的0.1 M NaNO 3背景溶液，再加入15 mg的固体样品（固体浓度为0.5 g/L），后置于转速 180 r/min，温度 25℃的摇床中振荡 24 h。且pH的变化通过0.1 M HNO 3和0.1 M NaOH来调节。所有样品每组设置3个平行处理。 The batch experimental reaction system for adsorbing As(V) and Cr(VI) on the Strychite minerals synthesized in Examples 1 to 7, Comparative Examples and β-FeOOH is to add 30 mL containing As(V) with a specified concentration into a 50 mL centrifuge tube. and 0.1 M NaNO 3 background solution of Cr(VI), then add 15 mg of solid sample (solid concentration is 0.5 g/L), and then place it in a shaker with a rotation speed of 180 r/min and a temperature of 25°C for 24 h. And the change of pH was adjusted by 0.1 M HNO 3 and 0.1 M NaOH. All samples were processed in three parallel groups per group.
吸附等温线实验：设定不同初始As(V)和Cr(VI)的浓度分别为5、15、30、60 和 100 mg/L，溶液pH维持在3。Adsorption isotherm experiment: Set different initial As(V) and Cr(VI) concentrations to 5, 15, 30, 60 and 100 mg/L respectively, and maintain the solution pH at 3.
pH吸附实验：吸附实验采用实施例3、实施例6以及对比例和晶种。设定pH分别为 2、3、4、5、6、7、8，初始As(V)和Cr(VI)浓度都为30 mg/L。pH adsorption experiment: The adsorption experiment uses Example 3, Example 6 and comparative examples and seed crystals. Set the pH to 2, 3, 4, 5, 6, 7, and 8 respectively, and the initial As(V) and Cr(VI) concentrations are both 30 mg/L.
吸附动力学实验：吸附实验采用实施例3、实施例6以及对比例和晶种。初始As(V)和Cr(VI)浓度都为30 mg/L，pH为3，采样时间点设为1、2、5、10、20、30、60、120、180、360、720、1080、1440分钟。Adsorption kinetics experiment: The adsorption experiment uses Example 3, Example 6, Comparative Examples and seed crystals. The initial As(V) and Cr(VI) concentrations are both 30 mg/L, pH is 3, and sampling time points are set to 1, 2, 5, 10, 20, 30, 60, 120, 180, 360, 720, 1080, and 1440 minutes.
以上三组实验反应结束后取上清液过 0.22 μm 滤膜，分别测定滤液As 和Cr的质量浓度。并计算不同实施例（不同晶种投加量）对As(V)和Cr(VI)的去除率和对应初始浓度的吸附容量，得到As(V)不同起始浓度的去除效果和吸附量如图7所示；得到Cr(VI)不同起始浓度的去除效果和吸附量如图8所示；pH对As(V)的去除影响如图9所示；pH对Cr(VI)的去除影响如图10所示；吸附动力学结果如图11所示。After the reaction of the above three groups of experiments, the supernatant was passed through a 0.22 μm filter membrane, and the mass concentrations of As and Cr in the filtrate were measured respectively. And calculate the removal rates of As(V) and Cr(VI) and the adsorption capacities corresponding to the initial concentrations of different embodiments (different seed crystal dosages), and obtain the removal effects and adsorption capacities of As(V) with different initial concentrations as follows: As shown in Figure 7; the removal effects and adsorption amounts of Cr(VI) at different initial concentrations are shown in Figure 8; the effect of pH on the removal of As(V) is shown in Figure 9; the effect of pH on the removal of Cr(VI) As shown in Figure 10; the adsorption kinetics results are shown in Figure 11.
由图7可知：在酸性条件下（pH为3），本发明所制备的实施例1~实施例7对As(V)的去除率明显强于对比例和β-FeOOH，特别是实施例6在As(V)为15、30、60 和 100 mg/L时吸附容量增加约2~4倍。It can be seen from Figure 7 that under acidic conditions (pH 3), the As(V) removal rate of Examples 1 to 7 prepared by the present invention is significantly stronger than that of the comparative example and β-FeOOH, especially Example 6 When As(V) is 15, 30, 60 and 100 mg/L, the adsorption capacity increases by about 2 to 4 times.
由图8可知：在酸性条件下（pH为3），本发明所制备的实施例1~实施例7对Cr(VI)的去除率都比对比例效果好，实施例3对Cr(VI)的去除效果最佳。It can be seen from Figure 8 that under acidic conditions (pH is 3), the removal rates of Cr(VI) prepared by Examples 1 to 7 prepared by the present invention are all better than those of the comparative example. Example 3 has a better removal rate of Cr(VI). The best removal effect.
由图9可知：本发明所制备的施氏矿物在酸性和中性条件下对As(V)的去除均大大优于对比例和晶种，对比例对As(V)的最佳吸附pH为7，而实施例3在pH 6~8去对As(V)除率已超过90%，实施例6在pH 2~8对As(V)除率均已超过90%，这表明实施例6对As(V)去除效果极强，且在As(V)初始浓度为30mg/L的体系中未达到吸附饱和。It can be seen from Figure 9 that the As(V) removal of the Schmitten mineral prepared by the present invention is much better than that of the comparative example and the seed crystal under both acidic and neutral conditions. The optimal adsorption pH of As(V) for the comparative example is: 7, while the As(V) removal rate of Example 3 at pH 6~8 has exceeded 90%, and the As(V) removal rate of Example 6 at pH 2~8 has exceeded 90%, which shows that Example 6 The removal effect of As(V) is extremely strong, and the adsorption saturation is not reached in the system with an initial concentration of As(V) of 30 mg/L.
由图10可知：本发明所制备的施氏矿物在酸性和中性条件下对Cr(VI)的去除效果均优于晶种，且不弱于对比例，实施例和对比例对Cr(VI)的最佳吸附pH均在5~6，且在pH 2~6对Cr(VI)的吸附能力逐渐增强，在pH 6~8对Cr(VI)的吸附能力又逐渐下降。晶种对As(V)和Cr(VI)去除能力均差于对比例，对比例又差于实施例，因此实施例对As(V)和Cr(VI)吸附能力的增强绝不是引入吸附能力更强的吸附剂造成的，本发现中的晶种起到对实施例合成的施氏矿物结构进行修饰的作用，指导施氏矿物的合成，形成了更多的吸附活性位点，或暴露了更多的吸附活性位点，提高了施氏矿物的吸附活性和吸附容量。It can be seen from Figure 10 that the Schmitten mineral prepared by the present invention has a better removal effect of Cr(VI) under acidic and neutral conditions than the seed crystal, and is not weaker than the comparative example. The Examples and Comparative Examples have better Cr(VI) The optimal adsorption pH of ) is 5~6, and the adsorption capacity of Cr(VI) gradually increases at pH 2~6, and the adsorption capacity of Cr(VI) gradually decreases at pH 6~8. The ability of the seed crystal to remove As(V) and Cr(VI) is worse than that of the comparative example, and the comparative example is worse than that of the example. Therefore, the enhancement of the adsorption capacity of As(V) and Cr(VI) in the example is by no means the introduction of adsorption capacity. Caused by stronger adsorbents, the seed crystals in the present invention play a role in modifying the structure of the Schrezgen mineral synthesized in the embodiment, guiding the synthesis of the Schrezfeldt mineral, forming more adsorption active sites, or exposing More adsorption active sites improve the adsorption activity and adsorption capacity of Shiite minerals.
由图11可知：实施例3和实施例6以及对比例的吸附动力学可知对As(V)和Cr(VI)的吸附在12h（720min）时均已到达平衡，且实施例6对As(V)和Cr(VI)的去除速率均高于对比例，吸附平衡时对As(V)和Cr(VI)的吸附容量均高于对比例。It can be seen from Figure 11: The adsorption kinetics of Examples 3, 6 and Comparative Examples show that the adsorption of As(V) and Cr(VI) has reached equilibrium at 12h (720min), and the adsorption of As(V) in Example 6 has reached equilibrium. The removal rates of As(V) and Cr(VI) are both higher than those of the comparative example, and the adsorption capacities of As(V) and Cr(VI) at adsorption equilibrium are both higher than those of the comparative example.
本发明***研究了β-FeOOH作为晶种介导生物合成纳米级施氏矿物的可行性，我们发现在β-FeOOH特定官能团（大量的羟基）的诱导作用下，在施氏矿物微生物成矿***中成功调节了施氏矿物的形态、结构和表面性质，增加官能团的数量，形成了更多的吸附活性位点，故而提高了施氏矿物对As(V)和Cr(VI)的去除率和吸附容量。此外，利用本发明制备的施氏矿物产量高，合成周期短，成本低廉，还在一定程度上克服了施氏矿物在酸性水体对As(V)和Cr(VI)污染治理效果差的困难，可应用于酸性矿山废水的治理。总之。该发明为生物合成的高性能吸附剂做出了贡献，对深化施氏矿物生物合成的认识具有重要意义。The present invention has systematically studied the feasibility of using β-FeOOH as a crystal seed to mediate the biosynthesis of nanoscale Strychite minerals. We found that under the induction of β-FeOOH specific functional groups (a large number of hydroxyl groups), the Strychite mineral microbial mineralization system It successfully adjusted the morphology, structure and surface properties of Strychite minerals, increased the number of functional groups, and formed more adsorption active sites, thus improving the removal rate and removal rate of As(V) and Cr(VI) by Strychtonite minerals. adsorption capacity. In addition, the Sichite mineral prepared by the present invention has high yield, short synthesis cycle and low cost. It also overcomes to a certain extent the difficulty of Srich mineral having poor effect on As(V) and Cr(VI) pollution control in acidic water bodies. It can be applied to the treatment of acid mine wastewater. Anyway. This invention has contributed to the development of high-performance adsorbents for biosynthesis and is of great significance to deepening the understanding of biosynthesis of Schneiderii minerals.
以上实施例仅为本发明较优的实施方式，仅用于解释本发明，而非限制本发明，本领域技术人员在未脱离本发明精神实质下所作的改变、替换、修饰等均应属于本发明的保护范围。The above embodiments are only preferred embodiments of the present invention and are only used to explain the present invention rather than limit the present invention. Changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit and essence of the present invention shall all belong to this invention. protection scope of the invention.

Claims (10)

  1. 一种添加外源晶种介导施氏矿物的生物合成方法，其特征在于，包括以下步骤：A method for adding exogenous crystal seeds to mediate the biosynthesis of Strychite minerals, which is characterized by including the following steps:
    （1）在硫酸亚铁溶液中加入β-FeOOH纳米晶种溶液，然后加入A. ferrooxidans休止细胞悬浮液，得混合液；(1) Add β-FeOOH nanocrystal seed solution to the ferrous sulfate solution, and then add A. ferrooxidans resting cell suspension to obtain a mixed solution;
    （2）将步骤（1）的混合液置于25~30℃培养42-72h，培养结束后；矿物沉淀洗涤、冷冻干燥、过筛，得添加外源晶种介导合成的施氏矿物。(2) Cultivate the mixed solution in step (1) at 25~30°C for 42-72 hours. After the culture is completed, the mineral precipitate is washed, freeze-dried, and sieved to add the exogenous seed-mediated synthesis of Schretz's mineral.
  2. 根据权利要求1所述的一种添加外源晶种介导施氏矿物的生物合成方法，其特征在于，步骤（1）所述A. ferrooxidans休止细胞悬浮液中A. ferrooxidans的密度为1×10 8 ~3×10 8 cells/ml； A biosynthetic method for adding exogenous crystal seeds to mediate Schreck's mineral according to claim 1, characterized in that the density of A. ferrooxidans in the A. ferrooxidans resting cell suspension in step (1) is 1× 10 8 ~3×10 8 cells/ml;
    所述β-FeOOH纳米晶种溶液的浓度为0.001~0.1g/mL。The concentration of the β-FeOOH nanocrystal seed solution is 0.001~0.1g/mL.
  3. 根据权利要求1所述的一种添加外源晶种介导施氏矿物的生物合成方法，其特征在于，步骤（1）所述混合液中硫酸亚铁的浓度为20~160 mMol/L；A biosynthetic method for adding exogenous crystal seeds to mediate Schmitten minerals according to claim 1, characterized in that the concentration of ferrous sulfate in the mixed solution of step (1) is 20~160 mMol/L;
    所述β-FeOOH纳米晶种溶液和混合液的体积比为2~128：:1000；The volume ratio of the β-FeOOH nanocrystal seed solution and the mixed solution is 2~128::1000;
    所述A. ferrooxidans休止细胞悬浮液和混合液的体积比为1:50~100。The volume ratio of the A. ferrooxidans resting cell suspension and the mixed solution is 1:50~100.
  4. 根据权利要求1所述的一种添加外源晶种介导施氏矿物的生物合成方法，其特征在于，步骤（2）所述培养在150~200 r/min摇床中培养；A biosynthetic method for adding exogenous crystal seeds to mediate Schreck's mineral according to claim 1, characterized in that the culture in step (2) is performed in a 150-200 r/min shaker;
        所述洗涤为去离子水洗涤；所述冷冻干燥的温度为-30 ~ -45℃，时间为12~36 h；所述过筛为过100~200目筛。The washing is deionized water washing; the freeze-drying temperature is -30 ~ -45°C and the time is 12 ~ 36 h; the sieving is passing through a 100 ~ 200 mesh sieve.
  5. 根据权利要求1所述的一种添加外源晶种介导施氏矿物的生物合成方法，其特征在于，步骤（1）所述β-FeOOH纳米晶种溶液的制备方法包括以下步骤：A biosynthetic method for adding exogenous crystal seeds to mediate Schretzite minerals according to claim 1, characterized in that the preparation method of the β-FeOOH nanocrystal seed solution in step (1) includes the following steps:
    氯化铁加入无水乙醇溶解，再加入去离子水混合拌匀得反应液，80~100 ℃反应36~54 h；反应结束后，离心、洗涤、冷冻干燥得到β-FeOOH纳米晶种；将所得的β-FeOOH纳米晶种加水超声分散得到β-FeOOH纳米晶种溶液。Dissolve ferric chloride in absolute ethanol, then add deionized water and mix well to obtain a reaction solution, react at 80~100°C for 36~54 hours; after the reaction is completed, centrifuge, wash, and freeze-dry to obtain β-FeOOH nanocrystal seeds; The obtained β-FeOOH nanocrystal seeds are added with water and ultrasonically dispersed to obtain a β-FeOOH nanocrystal seed solution.
  6. 根据权利要求5所述的一种添加外源晶种介导施氏矿物的生物合成方法，其特征在于，所述氯化铁为FeCl 3·6H 2O；所述反应液中氯化铁的浓度为0.2~0.4 Mol/L；所述无水乙醇和去离子水的体积比为1：1~1.5； A biosynthetic method for adding exogenous crystal seeds to mediate Schmitten minerals according to claim 5, characterized in that the ferric chloride is FeCl 3 ·6H 2 O; the ferric chloride in the reaction solution is The concentration is 0.2~0.4 Mol/L; the volume ratio of the absolute ethanol and deionized water is 1:1~1.5;
    所述洗涤为无水乙醇和去离子水洗涤至中性；所述冷冻干燥的时间为12~36h；The washing includes absolute ethanol and deionized water until neutral; the freeze-drying time is 12 to 36 hours;
    所述超声分散的时间为30~45分钟。The ultrasonic dispersion time is 30 to 45 minutes.
  7. 根据权利要求1所述的一种添加外源晶种介导施氏矿物的生物合成方法，其特征在于，所述A. ferrooxidans休止细胞悬浮液的制备方法包括以下步骤：A biosynthetic method for adding exogenous crystal seeds to mediate Schreck's mineral according to claim 1, characterized in that the preparation method of the A. ferrooxidans resting cell suspension includes the following steps:
    将9K培养基高温高压灭菌，接种A. ferrooxidans细菌，加入硫酸亚铁，调节pH，培养2~3天；过滤除去铁沉淀物，滤液离心后收集菌体，洗涤、悬浮得到A. ferrooxidans休止细胞悬浮液。Sterilize the 9K culture medium at high temperature and high pressure, inoculate A. ferrooxidans bacteria, add ferrous sulfate, adjust the pH, and culture for 2 to 3 days; filter to remove iron precipitates, collect the filtrate after centrifugation, wash and suspend to obtain A. ferrooxidans rest cell suspension.
  8. 根据权利要求7所述的一种添加外源晶种介导施氏矿物的生物合成方法，其特征在于，A method for adding exogenous crystal seeds to mediate the biosynthesis of Strych's mineral according to claim 7, characterized in that:
    所述离心的温度为4~7℃，离心力为10000~12000 g，时间为8~10分钟；The centrifugal temperature is 4~7°C, the centrifugal force is 10000~12000 g, and the time is 8~10 minutes;
    所述悬浮后的体积为培养基的1/50~1/100；The volume after suspension is 1/50~1/100 of the culture medium;
    所述调节pH为用H 2SO 4调节pH至2-3。 The pH adjustment is to use H 2 SO 4 to adjust the pH to 2-3.
  9. 权利要求1-8任一项所述的生物合成方法合成得到的添加外源晶种介导合成的施氏矿物。The Schmitten mineral synthesized by the biosynthetic method described in any one of claims 1 to 8 is mediated by the addition of exogenous seed crystals.
  10. 权利要求9所述的添加外源晶种介导合成的施氏矿物在去除水体中As(V)和Cr(VI)污染中的应用。The application of adding exogenous seed crystals to mediate the synthesis of Strychite minerals in removing As(V) and Cr(VI) pollution in water bodies according to claim 9.
     ​
PCT/CN2022/128476 2022-04-25 2022-10-31 Biosynthesis method for exogenous seed crystal-added mediated schwertmannite, as well as product and application of schwertmannite WO2023207005A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210440026.2A CN114713181B (en) 2022-04-25 2022-04-25 Biosynthesis method of exogenous seed crystal-added mediated Schwerner mineral, product and application thereof
CN202210440026.2 2022-04-25

Publications (1)

Publication Number Publication Date
WO2023207005A1 true WO2023207005A1 (en) 2023-11-02

Family

ID=82246348

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/128476 WO2023207005A1 (en) 2022-04-25 2022-10-31 Biosynthesis method for exogenous seed crystal-added mediated schwertmannite, as well as product and application of schwertmannite

Country Status (2)

Country Link
CN (1) CN114713181B (en)
WO (1) WO2023207005A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114713181B (en) * 2022-04-25 2023-02-14 华南理工大学 Biosynthesis method of exogenous seed crystal-added mediated Schwerner mineral, product and application thereof

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105601051A (en) * 2016-03-11 2016-05-25 山西农业大学 Biomineralization-based acidic mine wastewater treatment system and treatment method
CN106867921A (en) * 2015-12-11 2017-06-20 北京有色金属研究总院 The method that thiobacillus ferrooxidans and bacterium treatment acid wastewater in mine reclaim iron resource
CN109928510A (en) * 2019-01-29 2019-06-25 南京农业大学 A kind of Schwertmannite preparation method based on ZVI reduction coupling microorganism
WO2021048827A1 (en) * 2019-09-13 2021-03-18 University Of South Africa A process for treating acid mine drainage
RU2767952C1 (en) * 2021-07-07 2022-03-22 Федеральное государственное бюджетное научное учреждение "Федеральный исследовательский центр "Красноярский научный центр Сибирского отделения Российской академии наук" Method of producing ferrihydrite nanoparticles
CN114713181A (en) * 2022-04-25 2022-07-08 华南理工大学 Biosynthesis method of exogenous seed crystal-added mediated Schwerner mineral, product and application thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103910402A (en) * 2014-01-10 2014-07-09 周立祥 Granular Schwertmannite and its preparation method and use

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106867921A (en) * 2015-12-11 2017-06-20 北京有色金属研究总院 The method that thiobacillus ferrooxidans and bacterium treatment acid wastewater in mine reclaim iron resource
CN105601051A (en) * 2016-03-11 2016-05-25 山西农业大学 Biomineralization-based acidic mine wastewater treatment system and treatment method
CN109928510A (en) * 2019-01-29 2019-06-25 南京农业大学 A kind of Schwertmannite preparation method based on ZVI reduction coupling microorganism
WO2021048827A1 (en) * 2019-09-13 2021-03-18 University Of South Africa A process for treating acid mine drainage
RU2767952C1 (en) * 2021-07-07 2022-03-22 Федеральное государственное бюджетное научное учреждение "Федеральный исследовательский центр "Красноярский научный центр Сибирского отделения Российской академии наук" Method of producing ferrihydrite nanoparticles
CN114713181A (en) * 2022-04-25 2022-07-08 华南理工大学 Biosynthesis method of exogenous seed crystal-added mediated Schwerner mineral, product and application thereof

Also Published As

Publication number Publication date
CN114713181A (en) 2022-07-08
CN114713181B (en) 2023-02-14

Similar Documents

Publication Publication Date Title
Liao et al. Biosynthesis of schwertmannite by Acidithiobacillus ferrooxidans cell suspensions under different pH condition
Govarthanan et al. Non-toxic nano approach for wastewater treatment using Chlorella vulgaris exopolysaccharides immobilized in iron-magnetic nanoparticles
Gan et al. Adsorption of Cr (VI) and Cu (II) by AlPO4 modified biosynthetic Schwertmannite
Jiang et al. The effect of magnetic nanoparticles on Microcystis aeruginosa removal by a composite coagulant
Kuang et al. Preparation of triethylene-tetramine grafted magnetic chitosan for adsorption of Pb (II) ion from aqueous solutions
Peng et al. Biosorption of copper (II) by immobilizing Saccharomyces cerevisiae on the surface of chitosan-coated magnetic nanoparticles from aqueous solution
Mohanpuria et al. Biosynthesis of nanoparticles: technological concepts and future applications
Seifan et al. The role of magnetic iron oxide nanoparticles in the bacterially induced calcium carbonate precipitation
Gan et al. The influence of aluminum chloride on biosynthetic schwertmannite and Cu (II)/Cr (VI) adsorption
Thirunavukkarasu et al. Adsorption of acid yellow 36 onto green nanoceria and amine functionalized green nanoceria: comparative studies on kinetics, isotherm, thermodynamics, and diffusion analysis
Ofomaja et al. Synthesis and optimization of reaction variables in the preparation of pinemagnetite composite for removal of methylene blue dye
CN110652968A (en) Magnetic bacterium ball composite material loaded with reduced graphene oxide and preparation method thereof
CN113042519B (en) Biological type zero-valent iron sulfide material and preparation method and application thereof
WO2023207005A1 (en) Biosynthesis method for exogenous seed crystal-added mediated schwertmannite, as well as product and application of schwertmannite
Zhu et al. Controllable biosynthesis of nanoscale schwertmannite and the application in heavy metal effective removal
CN109569518B (en) Preparation method of cysteine functionalized magnetic hollow manganese ferrite nano composite adsorbent
CN112958043A (en) Preparation method of goethite/carboxylated cellulose nanocrystalline composite material for removing heavy metal ions
Feng et al. Hydroxyl, Fe2+, and Acidithiobacillus ferrooxidans jointly determined the crystal growth and morphology of schwertmannite in a sulfate-rich acidic environment
Ding et al. Efficient adsorption of Cr (VI) in acidic environment by nano-scaled schwertmannite prepared through pH regulation: characteristics, performances, and mechanism
Wang et al. Cr (VI) Removal from Aqueous Solution Using Starch and Sodium Carboxymethyl Cellulose-Coated Fe and Fe/Ni Nanoparticles.
CN111410752B (en) Hydrogel nanocomposite and preparation method and application thereof
CN113385139B (en) Schweitmann stone prepared by alkali neutralization method and application thereof
CN109012614B (en) Chitosan/KIT-6 type silicon-based composite material and preparation method and application thereof
CN113842900A (en) Preparation method of magnetic hectorite composite polymer heavy metal ion adsorbent
Gan et al. Biosynthesis of bifunctional iron oxyhydrosulfate by Acidithiobacillus ferroxidans and their application to coagulation and adsorption

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22939823

Country of ref document: EP

Kind code of ref document: A1