LU506396B1 - Method for preparing selenium-enriched modified biochar for cadmium adsorption - Google Patents
Method for preparing selenium-enriched modified biochar for cadmium adsorption Download PDFInfo
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- LU506396B1 LU506396B1 LU506396A LU506396A LU506396B1 LU 506396 B1 LU506396 B1 LU 506396B1 LU 506396 A LU506396 A LU 506396A LU 506396 A LU506396 A LU 506396A LU 506396 B1 LU506396 B1 LU 506396B1
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- selenium
- biochar
- enriched
- straw
- adsorption
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- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 title claims abstract description 65
- 229910052711 selenium Inorganic materials 0.000 title claims abstract description 65
- 239000011669 selenium Substances 0.000 title claims abstract description 65
- 238000001179 sorption measurement Methods 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 title claims abstract description 20
- 229910052793 cadmium Inorganic materials 0.000 title claims abstract description 16
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 title claims abstract description 16
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 48
- 238000003763 carbonization Methods 0.000 claims abstract description 13
- 239000010902 straw Substances 0.000 claims description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 239000003337 fertilizer Substances 0.000 claims description 19
- 239000002994 raw material Substances 0.000 claims description 18
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 230000002950 deficient Effects 0.000 claims description 5
- 230000007935 neutral effect Effects 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 5
- 241000209094 Oryza Species 0.000 abstract description 24
- 235000007164 Oryza sativa Nutrition 0.000 abstract description 24
- 235000009566 rice Nutrition 0.000 abstract description 24
- 239000010903 husk Substances 0.000 abstract description 16
- 239000002351 wastewater Substances 0.000 abstract description 12
- 229910001385 heavy metal Inorganic materials 0.000 abstract description 6
- 230000004048 modification Effects 0.000 abstract description 3
- 238000012986 modification Methods 0.000 abstract description 3
- 230000001737 promoting effect Effects 0.000 abstract description 3
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 abstract description 2
- 239000001110 calcium chloride Substances 0.000 abstract description 2
- 229910001628 calcium chloride Inorganic materials 0.000 abstract description 2
- 230000007246 mechanism Effects 0.000 abstract description 2
- 235000011148 calcium chloride Nutrition 0.000 abstract 1
- 229940091258 selenium supplement Drugs 0.000 description 56
- 239000000243 solution Substances 0.000 description 15
- 125000000524 functional group Chemical group 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 10
- 239000011148 porous material Substances 0.000 description 6
- BVTBRVFYZUCAKH-UHFFFAOYSA-L disodium selenite Chemical compound [Na+].[Na+].[O-][Se]([O-])=O BVTBRVFYZUCAKH-UHFFFAOYSA-L 0.000 description 5
- 238000000197 pyrolysis Methods 0.000 description 5
- 229960001471 sodium selenite Drugs 0.000 description 5
- 239000011781 sodium selenite Substances 0.000 description 5
- 235000015921 sodium selenite Nutrition 0.000 description 5
- 230000002378 acidificating effect Effects 0.000 description 4
- 239000012190 activator Substances 0.000 description 4
- 238000010668 complexation reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 159000000007 calcium salts Chemical class 0.000 description 3
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 238000005342 ion exchange Methods 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000004626 scanning electron microscopy Methods 0.000 description 3
- 229940082569 selenite Drugs 0.000 description 3
- MCAHWIHFGHIESP-UHFFFAOYSA-L selenite(2-) Chemical compound [O-][Se]([O-])=O MCAHWIHFGHIESP-UHFFFAOYSA-L 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000005341 cation exchange Methods 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 206010037660 Pyrexia Diseases 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229940065285 cadmium compound Drugs 0.000 description 1
- AQCDIIAORKRFCD-UHFFFAOYSA-N cadmium selenide Chemical compound [Cd]=[Se] AQCDIIAORKRFCD-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000000338 in vitro Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 125000000686 lactone group Chemical group 0.000 description 1
- 239000002957 persistent organic pollutant Substances 0.000 description 1
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical group C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 102000004169 proteins and genes Human genes 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 125000003396 thiol group Chemical group [H]S* 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
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
- B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
-
- 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
- B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
- B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
- B01J20/28057—Surface area, e.g. B.E.T specific surface area
- B01J20/28059—Surface area, e.g. B.E.T specific surface area being less than 100 m2/g
-
- 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
- C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
-
- 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
- B01J2220/00—Aspects relating to sorbent materials
- B01J2220/40—Aspects relating to the composition of sorbent or filter aid materials
- B01J2220/48—Sorbents characterised by the starting material used for their preparation
- B01J2220/4812—Sorbents characterised by the starting material used for their preparation the starting material being of organic character
- B01J2220/4825—Polysaccharides or cellulose materials, e.g. starch, chitin, sawdust, wood, straw, cotton
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/10—Biofuels, e.g. bio-diesel
Abstract
Disclosed is a method for preparing selenium-enriched modified biochar for cadmium adsorption. Selenium-enriched rice husks are impregnated in a hydrochloric acid solution of CaCl2 for 20 to 24 h, and the impregnated selenium-enriched rice husks are dried, and then carbonized at a carbonization temperature of 300°C to 700°C for 0.5 to 1.5 h. The selenium- enriched biochar prepared in the disclosure has a specific surface area of 31.79 m2/g. After modification, the selenium element in the biochar plays a special role in promoting the adsorption of Cd2+, and cooperates with other multiple mechanisms to improve the adsorption performance of heavy metal Cd2+ in wastewater, and an adsorption capacity for Cd2+ with a concentration of 100 mg/L is 51.7 mg/g.
Description
METHOD FOR PREPARING SELENIUM-ENRICHED MODIFIED
BIOCHAR FOR CADMIUM ADSORPTION
[0001] The disclosure relates to the technical field of heavy metal wastewater treatment, and in particular relates to a method for preparing selenium-enriched modified biochar for cadmium adsorption.
[0002] At present, cadmium contaminated wastewater is treated with a precipitation method, an ion exchange method, a membrane separation method, and an adsorption method. Biochar, due to its high carbon content, high stability, abundant surface functional groups, well-developed pores, and relatively high specific surface area and cation exchange capacity, may serve as an adsorbent for adsorbing heavy metals and organic pollutants in water and soil. Depending on different preparation raw materials, pyrolysis techniques, and pyrolysis conditions, physical and chemical properties such as a pore structure, density, specific surface area, pH, cation exchange capacity, and oxygen-containing functional groups of the biochar are different, and these different physical and chemical properties also result in different adsorption performance of heavy metal ions.
[0003] An object of the disclosure is to provide a method for preparing selentum-enriched modified biochar for cadmium adsorption. The prepared selenium-enriched modified biochar can effectively immobilize heavy metal cadmium through multiple action, thereby significantly improving the removal efficiency of Cd”* in wastewater.
[0004] The object of the disclosure is achieved by the following technical scheme:
[0005] a method for preparing selenium-enriched modified biochar for cadmium adsorption, where selenium-enriched rice husks are impregnated in a hydrochloric acid solution of CaCl, for 20 to 24 h, and the impregnated selenium-enriched rice husks are dried, and then carbonized at a carbonization temperature of 300°C to 700°C for 0.5 to 1.5 h.
[0006] Preferably, the carbonization is performed at 600°C to 700°C for 1 h.
[0007] Further, the drying is performed at 100°C to 105°C for 10 to 12 h.
[0008] Further, the hydrochloric acid solution of CaCl: is prepared by adding CaCl: into a LU506396 hydrochloric acid solution, where the pH of the solution is adjusted to 2 to 4, and the concentration of CaCl is 0.5 to 1.5 mol/L.
[0009] Further, the selenium-enriched rice husks are pretreated by spraying a selenium-enriched chelated water fertilizer solution onto rice husks or straw, where a selenium-containing main component of the selenium-enriched chelated water fertilizer solution is sodium selenite, with a concentration of 20 to 30 g/L.
[0010] Further, the impregnation is to heat the selenium-enriched rice husks in the hydrochloric acid solution of CaCl: to 80°C to 100°C and keep the heated selenium-enriched rice husks at this temperature for 1 to 2 h, followed by soaking at room temperature for 22 to 16 h.
[0011] In the prior art, the complexation detoxifying effect of selenium on cadmium is mainly exerted on the organism. After undergoing a series of reactions in the organism, selenite combines with the thiol groups of proteins in the body, and then Cd?” is complexed to form a selenium-cadmium compound, thereby achieving the effect of cadmium adsorption. However, there have been no reports on the complexation of Cd?* directly in vitro. Moreover, selenium enrichment in raw materials such as agricultural and forestry straw is usually achieved by spraying the selenite. During high-temperature pyrolysis, the selenite will be decomposed or lost, resulting in a lower selenium content in final prepared biochar. Moreover, most of retained selenium is ineffective, and thus the adsorption of Cd?* is not significant.
[0012] In the preparation process, it was found that after the raw material was soaked in the hydrochloric acid solution of CaCl, hydrochloric acid had a certain reducibility, and reacted with sodium selenite, such that the content and effectiveness of the selenium in the biochar could be significantly improved in the pyrolysis process, and the selenium had a certain complexation effect in a subsequent adsorption process of Cd**, which had a relatively good promoting effect on the adsorption of Cd*".
[0013] Furthermore, through calcium chloride modification, produced CaCOs makes Cd” effectively deposited on the surface of the biochar by physical precipitation, and more acidic functional groups are produced after pyrolysis under the action of the hydrochloric acid, and are directly complexed with Cd”. Moreover, the acidic functional groups react with CaCO; to form calcium salts, and the calcium salts make ion exchange with Cd”*. Thus, the removal efficiency of Cd?” is synergistically improved by a multiple adsorption removal method.
[0014] Most specifically, a method for preparing selenium-enriched modified biochar for LU506396 cadmium adsorption includes the following steps:
[0015] (1) pretreatment: agricultural and forestry straw or rice husks are taken as a raw material, the straw is crushed to 3 to 5 cm; the crushed raw material is washed, and then air dried, crushed and sieved through a 20 to 60-mesh sieve; selenium-enriched chelated water fertilizer is sprayed onto the surface of the treated straw; and then the straw sprayed with the water fertilizer is placed in a hydrochloric acid solution of CaCl, kept at 80°C to 100°C for 1 to 2 h, then allowed to stand at room temperature for 12 to 16 h, and finally dried at 100°C to 105°C for 10 to 12 h;
[0016] (2) carbonization: the pretreated raw material is carbonized in an oxygen-deficient environment at 300°C to 700°C for 0.5 to 1.5 h to obtain biochar; and
[0017] (3) washing: the biochar obtained after the carbonization is washed to neutral, and then the washed biochar is dried at 105°C, and then ground and sieved through a 100-mesh sieve to obtain selenium-enriched modified biochar.
[0018] The disclosure has the following technical effects:
[0019] The selenium-enriched biochar prepared in the disclosure has a specific surface area of 31.79 m°/g. After modification, the selenium element in the biochar plays a special role in promoting the adsorption of Cd”*, and cooperates with other multiple mechanisms to improve the adsorption performance of heavy metal Cd?" in wastewater, and an adsorption capacity for Cd?" with a concentration of 100 mg/L is 51.7 mg/g.
[0020] FIG. 1: Scanning electron microscopy images of rice straw selenium-enriched biochar prepared in Example 1 of the disclosure with Cd?” adsorbed.
[0021] FIG. 2: Infrared spectrogram of rice straw selenium-enriched biochar prepared in
Example 1.
[0022] FIG. 3: Comparison diagram illustrating an adsorption capacity of rice straw selenium- enriched biochar prepared in Example 1.
[0023] FIG. 4: Adsorption capacities of rice straw selenium-enriched biochar prepared in
Example 1 of the disclosure for different concentrations of Cd””.
[0024] FIG. 5: Adsorption capacities of rice straw selenium-enriched biochar prepared with different activators for Cd?*.
DETAILED DESCRIPTION OF THE EMBODIMENTS LU506396
[0025] Example 1
[0026] A method for preparing selenium-enriched modified biochar for cadmium adsorption includes the following steps:
[0027] (1) pretreatment: agricultural and forestry straw or rice husks were taken as a raw material; the straw was crushed to 3 to 5 cm; the crushed straw was washed, and then air dried, crushed and sieved through a to 40-mesh sieve; selentum-enriched chelated water fertilizer was sprayed onto the surface of the treated straw; and then the straw sprayed with the water fertilizer was placed in a hydrochloric acid solution of CaCl», kept at 90°C for 1.5 h, then allowed to stand at room temperature for 14 h, and finally dried at 105°C for 12 h;
[0028] (2) carbonization: the pretreated raw material was carbonized in an oxygen-deficient environment at 700°C for 0.5 h to obtain biochar; and
[0029] (3) washing: the biochar obtained after the carbonization was washed to neutral, and then the washed biochar was dried at 105°C, and then ground and sieved through a 100-mesh sieve to obtain selenium-enriched modified biochar.
[0030] A selenium-containing main component of the selenium-enriched chelated water fertilizer is sodium selenite, with a concentration of to 20 g/L.
[0031] The scanning electron microscopy image of the selenium-enriched modified biochar prepared in this example is as shown in FIG. 1 (b), where the selenium-enriched modified biochar has a rough surface and abundant pore sizes, and a specific surface area of 31.79 m?%/g.
[0032] Comparative Example 1:
[0033] Unlike in Example 1, straw sprayed with selenium-enriched chelated water fertilizer in this scheme was allowed to stand and be soaked in a CaCl, aqueous solution for 20 h at room temperature, and the remaining steps are the same as those in Example 1.
[0034] The scanning electron microscopy image of the modified biochar prepared in this scheme is as shown in FIG. 1 (a), which clearly shows that the pore size structure of the surface of the modified biochar prepared is not as abundant as that of the selenium-enriched modified biochar prepared in the disclosure, and the modified biochar has a specific surface area of 20.23 m%/g.
[0035] Comparative Example 2:
[0036] Unlike in Example 1, the straw raw material in the disclosure was not sprayed with LU506396 selenium-enriched chelated water fertilizer, was washed and then directly placed in a hydrochloric acid solution of CaCl», and the remaining steps are the same as those in Example 1.
[0037] Since the modified biochar prepared in this scheme was not sprayed with the selenium- 5 enriched chelated water fertilizer, there were no more metal ions to react with hydrochloric acid, such that the hydrochloric acid seriously etched the straw at high temperature, causing some of pores in the straw to collapse, and the specific surface area to be sharply reduced compared with that in Example 1, which was only 17.64 m*/L.
[0038] The pH of the Cd” wastewater with a concentration of 100 mg/L was adjusted to 5.0.2 g of the biochar prepared in each of Example 1, Comparative Example 1, and Comparative
Example 2 was added to every 100 mL of wastewater. Shaking was performed at 150 rpm for 2 h.
Then the wastewater with the biochar is passed through 0.45 um of hydrophilic filter membrane.
The concentration of Cd** in the wastewater was determined by flame atomic adsorption spectrophotometry. An equilibrium adsorption capacity was worked out according to changes in the concentration of Cd?” before and after adsorption. As shown in FIG. 3, adsorption capacities of the biochar prepared in Example 1, the biochar prepared in Comparative Example 1, and the biochar prepared in Comparative Example 2 for Cd?” were 51.7 mg/g, 41.4 mg/g, and 40.1 mg/g, respectively. By adjusting the concentration of Cd?” in the wastewater to 80 mg/L, 100 mg/L, 120 mg/L, 180 mg/L, and 200 mg/L, corresponding equilibrium adsorption capacities of the selenium-enriched modified biochar prepared in Example 1 were 48.1 mg/g, 51.7 mg/g, 55.4 mg/g, 47.8 mg/g, and 59.2 mg/g as measured.
[0039] Surface functional groups of the biochar were determined by Boehm titration, and the test results are as shown in Table 1.
Table 1:
Biochar Specific surface area
Carboxyl Lactone group | Phenolic
IE ==
Comparative | 20.23 0.42 0.084 2.45 LUS06396 =
Comparative | 17.64 0.45 0.078 2.61 =
[0040] Due to the increase of functional groups such as carboxyl and hydroxyl in the prepared biochar, these functional groups are complexed with Cd”, thereby improving the removal efficiency of Cd?*: —COOH+CE+H;0—CO0CE +H;0° ; en QOH CAH Ho OO Cd + HAO"
[0041] In Comparative Example 1, the straw was subjected to selenium enrichment treatment , but was not modified with the hydrochloric acid solution of CaCl». Therefore, after high- temperature treatment, the selenium in the straw failed to promote the adsorption removal of
Cd”, and its acidic functional groups were not increased. The efficiency of removing Cd** by complexation of the functional groups was decreased, and ion exchange between calcium salts produced by the acidic functional groups and CaCOs and Cd** also decreased. Therefore, the overall removal efficiency of Cd” was relatively low. In Comparative Example 2, since the selenium-enriched chelated water fertilizer was not sprayed, there were no more metal ions to react with the hydrochloric acid, such that the hydrochloric acid seriously etched the straw at high temperature, causing some of pores in the straw to collapse, the specific surface area to be reduced, and each functional group to lose its site, which inhibited the increase to a certain extent.
[0042] Example 2
[0043] A method for preparing selenium-enriched modified biochar for cadmium adsorption includes the following steps:
[0044] (1) pretreatment: rice straw was taken as a raw material; the rice straw was crushed to 3 to 5 cm; the crushed raw material was washed, and then air dried, crushed and sieved through a to 20-mesh sieve; selenium-enriched chelated water fertilizer was sprayed onto the surface of the treated raw material; and then the raw material sprayed with the water fertilizer was placed in a hydrochloric acid solution of CaCl, kept at 100°C for 1 h, then allowed to stand at room LU506396 temperature for 12 h, and finally dried at 105°C for 10 h;
[0045] (2) carbonization: the pretreated raw material was carbonized in an oxygen-deficient environment at 600°C for 0.5 h to obtain biochar; and
[0046] (3) washing: the biochar obtained after the carbonization was washed to neutral, and then the washed biochar was dried at 105°C, and then ground and sieved through a 100-mesh sieve to obtain selenium-enriched modified biochar.
[0047] A selenium-containing main component of the selenium-enriched chelated water fertilizer is sodium selenite, with a concentration of to 30g/L.
[0048] The adsorption capacity of the rice straw selenium-enriched modified biochar prepared in this example for Cd?" was 48.9 mg/g in wastewater in which the concentration of Cd”” was 100 mg/L.
[0049] Example 3
[0050] A method for preparing selenium-enriched modified biochar for cadmium adsorption includes the following steps:
[0051] (1) pretreatment: rice husks were taken as a raw material; the rice husks were washed, and then air dried, crushed and sieved through a to 60-mesh sieve; selenium-enriched chelated water fertilizer was sprayed onto the surface of the treated straw; and then the straw sprayed with the water fertilizer was placed in a hydrochloric acid solution of CaCl», kept at 80°C for 2 h, then allowed to stand at room temperature for 16 h, and finally dried at 100°C for 12 h;
[0052] (2) carbonization: the pretreated raw material was carbonized in an oxygen-deficient environment at 300°C for 1.5 h to obtain biochar; and
[0053] (3) washing: the biochar obtained after the carbonization was washed to neutral, and then the washed biochar was dried at 105°C, and then ground and sieved through a 100-mesh sieve to obtain selenium-enriched modified biochar.
[0054] A selenium-containing main component of the selenium-enriched chelated water fertilizer is sodium selenite, with a concentration of to 25g/L.
[0055] The adsorption capacity of the selenium-enriched modified biochar prepared in this example for Cd”* was 32.6 mg/g in wastewater in which the concentration of Cd?” was 100 mg/L.
[0056] In the preparation process, it was attempted to employ common activators such as KOH,
NaOH, ZnCl», and BaCl> to replace the hydrochloric acid solution of CaCl, for the treatment of selenium-enriched rice husks. The adsorption performance of the prepared rice husk biochar for LU506396
Cd” in the wastewater in which the concentration of Cd** is 100 mg/L is as shown in FIG. 5.
The adsorption performance of the biochar prepared from selenium-enriched straw treated with various activators for Cd?* did not fluctuate significantly, but was significantly improved compared to that of selenium-enriched straw without activators. After hydrochloric acid was added into BaCl,, heat treatment was performed according to the method of the disclosure, the prepared selenium-enriched rice husk modified biochar had a slight improvement in the adsorption capacity for Cd””. However, in a scheme of rice husks not subjected to selenium enrichment treatment, after the hydrochloric acid and CaCl: were added for the synergistic treatment, the adsorption performance decreased slightly.
Claims (2)
1. A method for preparing selenium-enriched modified biochar for cadmium adsorption, comprising the following steps: (1) pretreatment: agricultural and forestry straw is taken as a raw material; the straw is crushed to 3 to 5 cm; the crushed straw is washed, and then air dried, crushed and sieved through a 20 to 60- mesh sieve; selenium-enriched chelated water fertilizer is sprayed onto the surface of the treated straw; and then the straw sprayed with the water fertilizer is placed in a hydrochloric acid solution of CaCl,, kept at 80°C to 100°C for 1 to 2 h, then allowed to stand at room temperature for 12 to 16 h, and finally dried at 100°C to 105°C for 10 to 12 h; (2) carbonization: the pretreated raw material is carbonized in an oxygen-deficient environment at 600°C to 700°C for 0.5 h to obtain biochar; and (3) washing: the biochar obtained after the carbonization is washed to neutral, and then the washed biochar is dried at 105°C, and then ground and sieved through a 100-mesh sieve to obtain selenium-enriched modified biochar.
2. The method for preparing selenium-enriched modified biochar for cadmium adsorption according to claim 1, wherein the hydrochloric acid solution of CaCl: is prepared by adding CaCl: into a hydrochloric acid solution, wherein the pH of the solution is adjusted to 2 to 4, and the concentration of CaClz is 0.5 to 1.5 mol/L.
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| CN202210798929.8A CN115337917B (en) | 2022-07-08 | 2022-07-08 | Preparation method of selenium-rich modified biochar for adsorbing cadmium |
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| US20080207443A1 (en) * | 2007-02-28 | 2008-08-28 | Kishor Purushottam Gadkaree | Sorbent comprising activated carbon, process for making same and use thereof |
| CN102849675B (en) * | 2011-06-28 | 2015-08-12 | 国家纳米科学中心 | The preparation of nano composite material and preparation method thereof and water treatment, method and device |
| CN103920461B (en) * | 2014-04-11 | 2016-08-24 | 上海交通大学 | Magnetic bio charcoal quantum dot complex adsorbent and preparation and application thereof |
| CN106582516A (en) * | 2016-11-08 | 2017-04-26 | 浙江工业大学 | Nano-selenium -adsorbed activated carbon and biosynthesis and application thereof |
| CN108212080B (en) * | 2017-12-12 | 2019-05-31 | 江苏省农业科学院 | A kind of preparation method and application of composite modified stalk active particle charcoal adsorbent material |
| CN109603747B (en) * | 2018-12-21 | 2020-02-07 | 福州大学 | Modified coconut shell biochar, preparation method thereof and method for adsorbing heavy metal |
| CN109719123A (en) * | 2019-02-14 | 2019-05-07 | 中国科学院地球化学研究所 | A method of rice enrichment inorganic mercury and methyl mercury are reduced using sodium selenite modification biological charcoal |
| CN110327882B (en) * | 2019-07-11 | 2020-03-27 | 江西省科学院 | Preparation method and application of multiposition activated and modified reed-triarrhena sacchariflora biochar |
| CN110586046A (en) * | 2019-09-27 | 2019-12-20 | 常州大学 | Preparation method of organic modified biochar for treating heavy metal cadmium in wastewater |
| CN114231455A (en) * | 2021-12-21 | 2022-03-25 | 南华大学 | Biological pellet, immobilized microsphere, preparation method and application thereof |
| CN115337917B (en) * | 2022-07-08 | 2023-06-02 | 重庆文理学院 | Preparation method of selenium-rich modified biochar for adsorbing cadmium |
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| CN115337917A (en) | 2022-11-15 |
| WO2024007797A1 (en) | 2024-01-11 |
| CN115337917B (en) | 2023-06-02 |
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