CN112206742B - Porous oxide adsorption material for efficiently removing harmful ions in water - Google Patents
Porous oxide adsorption material for efficiently removing harmful ions in water Download PDFInfo
- Publication number
- CN112206742B CN112206742B CN201910614046.5A CN201910614046A CN112206742B CN 112206742 B CN112206742 B CN 112206742B CN 201910614046 A CN201910614046 A CN 201910614046A CN 112206742 B CN112206742 B CN 112206742B
- Authority
- CN
- China
- Prior art keywords
- adsorption
- transition metal
- precursor
- metal oxide
- water
- Prior art date
- Legal status (The legal status 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 status listed.)
- Active
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
- B01J20/06—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04
-
- 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
- B01J20/28002—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 physical properties
- B01J20/28004—Sorbent size or size distribution, e.g. particle size
-
- 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
- B01J20/28014—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 form
- B01J20/28016—Particle form
- B01J20/28019—Spherical, ellipsoidal or cylindrical
-
- 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
- B01J20/28014—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 form
- B01J20/28042—Shaped bodies; Monolithic structures
-
- 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
-
- 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
- B01J20/28061—Surface area, e.g. B.E.T specific surface area being in the range 100-500 m2/g
-
- 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
- B01J20/30—Processes for preparing, regenerating, or reactivating
-
- 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
- C02F2101/006—Radioactive 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
- C02F2101/103—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
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/16—Regeneration of sorbents, filters
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
The invention relates to a transition metal oxide material for water pollution control, which can remove harmful metal ions such as chromium (VI), arsenic (V), lead (I1), uranium (VI), cadmium (I1) and the like in water to reach the drinking water standard. Chromium (VI), arsenic (V) can be adsorbed to 10ppb or less, and lead (II), cadmium (II), uranium (VI) to 1ppb or less. The adsorbent has the general formula M x O y The method comprises the steps of carrying out a first treatment on the surface of the Wherein M is selected from one or two transition metal elements of Zr, ti, fe, mn, mo, W and the like; and x is more than or equal to 1 and less than or equal to 2, and y is more than or equal to 1 and less than or equal to 5. The preparation of the material adopts a micro etching technology, and the accurate selective etching ensures that the material has the characteristics of rich pore structures, high density hydroxyl groups, high specific surface area and the like, and the characteristics ensure that the adsorbent has strong adsorption force on harmful ions, thereby achieving the effect of high-efficiency removal. In addition, the material has good recycling performance, simple synthesis process and low cost, and has wide prospect in the aspect of water pollution control.
Description
Technical Field
The invention belongs to the technical field of water pollution treatment materials, and particularly relates to a porous transition metal oxide with low crystallinity.
Technical Field
With the increasing population of the world and the advancing industrialization process, the problem of water pollution is increasingly focused worldwide, and particularly the problem of pollution of drinking water by harmful metal and nonmetal ions is ubiquitous in all parts of the world, which threatens the health of human beings. Chromium (VI), lead (II), arsenic (V), cadmium (II), uranium (VI) and other ions are common harmful elements in water and are derived from waste liquid discharged from various industrial production industries such as metallurgy, electroplating, power generation and the like. The compounds are not naturally degradable or contain radioactivity, causing serious health problems in humans. The ministry of health in China prescribes in sanitary Standard for Drinking Water (GB 5749-2006) that the limit value of chromium (VI) contained in drinking water is 50ppb, the limit value of cadmium (II) is 5ppb,lead (II) limit 10ppb, arsenic (V) limit 10ppb, total alpha radioactivity limit 0.5Bq L -1 . The water purification modes adopted at present mainly comprise technologies such as adsorption, ion exchange, membrane separation and the like. Wherein the adsorption method has the advantages of simple operation, economy, high efficiency, flexible use mode and the like, and is one of the technologies with the best application prospect [ Khin M M, nair A S, babu V J, et al A review on nanomaterials for environmental remediation [ J ]].Energy&Environmental Science,2012,5(8):8075-8109.]. Commercial adsorbent materials include activated carbon, molecular sieves, polymeric compounds, biomass materials, transition metal oxides, and the like. Although adsorbent materials are diverse and some have very high adsorption capacities, the bottleneck of the current technology is adsorption under trace amounts, which is difficult to remove by existing adsorbents when the concentration of these harmful metals is low to some extent (< 5 ppm). Almost no adsorbent can directly remove trace chromium (VI), cadmium (II), lead (II) and other ions in water to reach the standard of drinking water. In particular, chromium (VI) exists in the form of anions in water, is easily diffused in soil having electronegativity, and is difficult to precipitate and adsorb. At present, no good material capable of adsorbing chromium (VI) to below 50ppb exists. Therefore, there is a need to develop new materials capable of thoroughly adsorbing harmful ions in water to achieve drinking water standards.
Distribution coefficient K d Is to measure the adsorption capacity, K of the adsorbent under the condition of extremely low concentration of the adsorbent d The higher the value, the stronger the adsorption capacity, and the following calculation formula is adopted:
K d =(C 0 -C e )V/C e m(mL g -1 )
where V (mL) is the volume of the adsorbate solution, C 0 (mg L -1 Or ppm) and C) e (mg L -1 Or ppm) is the initial and equilibrium concentrations of the adsorbent, respectively, and m (g) is the mass of adsorbent used.
At present, active carbon, molecular sieve, high molecular material, biomass material, sulfide, oxide and other materials have been studied as harmful ion adsorbents. Partition coefficient K of commercial activated carbon adsorption chromium (VI) d The value can reach 8 x 10 3 [Barkat M,Nibou D,Chegrouche S,et al. Kinetics and thermodynamics studies of chromium(VI)ions adsorption onto activated carbon from aqueous solutions[J].Chemical Engineeringand Processing:Process Intensification,2009,48(1): 38-47.]. The active carbon prepared by carbonizing the hard shell of the wood apple with concentrated sulfuric acid can remove 95 percent of chromium (VI) and has the adsorption capacity of 151.51mg g -1 [Doke K M,Khan E M.Equilibrium,kinetic and diffusion mechanism of Cr(VI)adsorption onto activated carbon derived from wood apple shell[J].Arabian Journal of Chemistry,2017,10: S252-S260.]. Partition coefficient K of MCM-41/ZSM composite molecular sieve adsorption chromium (VI) d A value of 1.87 x 10 3 [Kazemian H,Mallah M H.Removal of chromate ion from contaminated synthetic water using mcm-41/zsm-5 composite[J]. Journal of Environmental Health Science&Engineering,2008,5(1):73-77.]. Metal organic resin for removing chromium (VI) by anion exchange method, partition coefficient K d The value can reach 1.2-5.5 x 10 4 The adsorption capacity reaches 230-240mg g -1 [Rapti S, Pournara A,Sarma D,et al.Selective capture of hexavalent chromium from an anion-exchange column of metal organic·resin-alginic acid composite[J].Chemical science,2016,7(3):2427-2436.]. Using MoS 4 2 The intercalated layered double hydroxide can adsorb lead (II), silver (I), mercury (II) and the like, and can adsorb lead (II), silver (I), mercury (II) to less than 1ppb, and has partition coefficient K d Up to 10 7 [Ma L,Wang Q,Islam S M,et al.Highly selective and efficient removal of heavy metals by layered double hydroxide intercalated with the MoS42-ion[J].Journal of the American Chemical Society,2016,138(8):2858-2866.]. polypyrrole/MoS 4 2 The complex can remove lead (II), silver (I) and mercury (II) to 99.6%, and the distribution coefficient K is remained below 2ppb d Up to 10 7 [Xie L,Yu Z,Islam S M,et al.Remarkable Acid Stability of Polypyrrole-MoS4:A Highly Selective and Efficient Scavenger of Heavy Metals Over a Wide pH Range[J].Advanced Functional Materials,2018,28(20):1800502.]. These studies have good application prospects, but at present have a number of problems, such as the fact that the highest partition coefficient of the adsorbents of chromium (VI) is currently only 10 4 The requirements in terms of treating drinking water are still not met. Although materials for adsorbing lead (II), cadmium (II) and the like have excellent adsorption performance, almost all materials are sulfides, secondary pollution is caused in use, and a great problem exists.
Transition metal oxides such as iron oxide, titanium dioxide and composite oxides have received extensive attention from researchers as harmful ion adsorbents because of their advantages of environmental protection, innocuity, physical and chemical corrosion resistance, recyclability, and the like. The prior methods for preparing the transition metal adsorbent mainly comprise a sol-gel method, a precipitation method and a traditional hydrothermal method. Grssol and the like adopt a precipitation method to precipitate ferric nitrate under alkaline conditions to obtain nano ferric oxide; chen et al used ferric chloride and hydrochloric acid to precipitate at 100deg.C for two days to give nano ferric oxide; hu et al used a sol-gel process to prepare iron oxide. The size of the ferric oxide nano particles prepared by the preparation method is 3.8-100nm, and the chromium (VI) adsorption capacity can reach 19.2mg g -1 Copper (II) adsorption can reach 149.25mg g -1 [Hua M,Zhang S,Pan B,et al.Heavy metal removal from water/wastewater by nanosized metal oxides:a review[J].Journal of hazardous materials,2012,211:317-331.]. Chen et al synthesized porous ZrO using a sol-gel method using hexadecylamine, tetrabutyl titanate, and zirconium n-butoxide as raw materials 2 /TiO 2 Ball, the capacity of adsorbing chromium (VI) reaches 25.4mg g -1 And has good recycling properties [ Chen D, cao L, hanley T L, et al facility synthesis of monodisperse mesoporous zirconium titanium oxide microspheres with varying compositions and high surface areas for heavy metal ion sequestration [ J ]].Advanced Functional Materials,2012,22(9):1966-1971.]. Wang et Al hydrothermally obtained Mg-Al LDH/MnO by a mixture of magnesium nitrate, aluminum nitrate, urea, potassium sulfate and potassium peroxodisulfate in water at 120-180 ℃ for 12 hours 2 The removal rate of lead (II) can reach 96.73 percent [ Bo L, li Q, wang Y, et al, one-pot hydrothermal sy ]nthesis of thrust spherical Mg·Al layered double hydroxides/MnO 2 and adsorption for Pb(II)from aqueous solutions[J].Journal of Environmental Chemical Engineering,2015,3(3):1468-1475.]. The oxide adsorbent synthesized by the method has certain adsorption performance, and has great potential in practical application as an oxide. However, due to limitations of the synthesis methods, the oxide adsorbents synthesized by these methods currently have disadvantages in that adsorption performance is not superior enough, research contents are mostly limited to adsorption capacity or adsorption rate, and efficient trace adsorption is rarely involved. There is currently no oxide adsorbent capable of adsorbing trace amounts of harmful ions to directly meet potable water standards.
Therefore, development of a new method for preparing transition metal oxide is urgently needed, the surface groups of the adsorbent are regulated and controlled, and the affinity between the adsorbent and the adsorbate is enhanced so as to achieve the aim of efficient trace adsorption. The aim is that the residual quantity of harmful ions in the treated water is far lower than the national standard of drinking water, thereby protecting the health of human beings.
Disclosure of Invention
The invention aims at solving the problem that trace harmful ions in water are difficult to remove and reach the standard of drinking water, and synthesizes the transition metal oxide adsorbent which can almost thoroughly remove trace harmful ions (chromium, lead, arsenic, uranium and the like) in water. The harmful ions in water, chromium (VI), can be adsorbed from 2010ppb to < 6ppb, lead (II) from 2000ppb to < 0.06ppb, uranium (VI) from 2000ppb to < 0.03ppb, arsenic (V) from 1000ppb to < 10ppb, and cadmium (II) from 2000ppb to < 1ppb. Adsorption partition coefficient K d The values of chromium (VI) and arsenic (V) can reach more than 10 5 ml g -1 Lead (II), uranium (VI) and cadmium (II) can reach more than 10 8 ml g -1 Is the highest value in the current research. Meanwhile, the catalyst has the advantages of quick adsorption and good recycling performance.
The invention adopts the technical scheme that: a porous transition metal oxide is used as an adsorbent, and the general formula is M x O y Wherein M is selected from one or more transition metal elements of Zr, ti, fe, mn, mo, W and the like; x is more than or equal to 1 and less than or equal to 2, and y is more than or equal to 1 and less than or equal to 5.
Further, the transition metal oxide has the following characteristics:
1) The surface is rich in hydroxyl, the hydroxyl oxygen content in the spectrum peak of the X-ray photoelectron spectrum oxygen reaches 50% -80%, the hydroxyl density can reach 72 hydroxyl groups per square nanometer, the surface has strong affinity with harmful metal ions, and the surface can form chelation with the harmful ions.
2) Amorphous or low crystalline phase, no obvious diffraction peak or low intensity of diffraction peak of X-ray powder diffraction result.
3) The particle morphology and the size are various, the particle morphology can be regulated and controlled to be spherical, polyhedral, star-shaped, hollow and the like, and the particle size is 1 nanometer to 100 micrometers.
4) Has a large number of micro/nano hole structures, and nitrogen adsorption and desorption experiments prove that a large number of mesopores or micropores exist and have the structure as high as 70-300m 2 g -1 Is a specific surface area of (a).
Further, the transition metal oxide adsorbent was obtained using the following microetching method:
1) Synthesis of multicomponent composite oxide A a M x O y Precursor, A is alkali metal or alkaline earth metal element, M is one or two transition metal elements of Zr, ti, fe, mn, mo, W and the like; a is more than or equal to 1 and less than or equal to 4, x is more than or equal to 1 and less than or equal to 2, and y is more than or equal to 1 and less than or equal to 5. The A is a M x O y The precursor synthesis method is generally carried out by hydrothermal method or high temperature solid phase method, and can be prepared by the prior art, such as BaZrO as described in Moreira et al 3 [Moreira M L, Andrés J,Mastelaro V R,et al.On the reversed crystal growth of BaZrO 3 decaoctahedron: shape evolution and mechanism[J].CrystEngComm,2011,13(19):5818-5824.]. Hollow BaZrO as described in Dong et al 3 [Dong Z,Ye T,Zhao Y,et al.Perovskite BaZrO 3 hollow micro-and nanospheres:controllable fabrication,photoluminescence and adsorption of reactive dyes[J].Journal of Materials Chemistry,2011,21(16):5978-5984.]. The synthesized precursor can have various shapes including spherical, polyhedral, star-shaped, hollow, and the like. The synthesized particle size is 1 nanometer to 10 micrometersThe rice is unequal.
2) The precursor and the acid are mixed according to the proportion and are put under hydrothermal conditions for etching. The selected acid can be organic acid such as hydrochloric acid, nitric acid, formic acid, acetic acid, etc. or inorganic acid. Mixing and stirring the precursor, the acid and the water according to a certain molar ratio, putting the mixture into a high-pressure reaction container, and heating for a certain time. And centrifugally separating, cleaning and drying the product to obtain the product. Reference may be made to specific examples of embodiments for specific steps. Through the etching reaction of the step, the A element of the precursor is dissolved out, and the general formula of the product is M x O x M is one or two transition metal elements selected from Zr, ti, fe, mn, mo, W and the like; x is more than or equal to 1 and less than or equal to 2, and y is more than or equal to 1 and less than or equal to 5. After etching reaction, the product keeps the original shape of the precursor, namely the product can have the shapes of sphere, polyhedron, star, hollow and the like, and the particle size is 1 nanometer to 10 micrometers.
Compared with the existing adsorbent, the adsorbent prepared by the microetching technology has outstanding adsorption performance on trace harmful ions, and the reason is that:
1) Microetching under acidic conditions promotes the exchange of cations and protons (H) in the precursor particles to form high-density inner surface hydroxyl groups, and has strong adsorption capacity on harmful ions. The microetching process is to dissolve out the alkali metal or alkaline earth metal in the precursor under the acid condition, and a large amount of protons (H) are exchanged with the alkali metal or alkaline earth metal to form hydroxyl groups on the inner surface. The high-density hydroxyl can form chelation to harmful ions, and has extremely strong adsorption force, so that the harmful ions can be thoroughly removed.
2) The micro-etching hydrothermal reaction realizes accurate selective etching. Unlike the traditional bottom-up hydrothermal reaction, the micro-etching method is a top-down hydrothermal method, and the precursor is selectively partially etched to realize accurate pore-forming, so that rich pore channel structures and high specific surface area are formed, the anchoring of harmful ions is enhanced, and the adsorption capacity is increased.
3) The morphology of the adsorbent is regulated and controlled through precursor induction. The morphology of the precursor is reserved for the transition metal oxide product formed by using microetching preparation, so that the morphology of the precursor which is favorable for adsorption, such as hollow morphology, star morphology and the like, is selected, the mass transfer process of adsorption can be promoted, and the specific surface area can be increased.
Sample characterization
The method comprises the steps of collecting morphology and ultrastructural information of a sample by using a scanning electron microscope and a transmission electron microscope, collecting sample structure information by using an X-ray diffractometer, collecting sample hole structure information by using a specific surface area tester, obtaining sample surface composition information by using an X-ray photoelectron spectrum, and obtaining the ion concentration of hexavalent chromium by using an inductively coupled plasma emission spectrum and a mass spectrum.
Drawings
FIG. 1 shows a precursor hollow BaZrO prepared by the present invention 3 Hollow porous ZrO of product 2 Scanning electron microscope photographs of (2).
FIG. 2 shows a hollow porous ZrO produced by the present invention 2 Transmission electron microscope photographs of (2).
FIG. 3 shows the precursor hollow BaZrO prepared by the present invention 3 Hollow porous ZrO of product 2 X-ray powder diffraction pattern of (2) and ZrO 2 Nitrogen adsorption and desorption curves of (3).
FIG. 4 shows a hollow porous ZrO produced by the present invention 2 Isothermal adsorption curve, adsorption kinetics curve, adsorption performance and cycle performance of hexavalent chromium in aqueous solution under different pH environments.
FIG. 5 shows a precursor star-shaped BaZr prepared according to the invention x Ti 1-x O 3 (x=0.2-0.8), the product star-shaped porous Zr x Ti 1-x O 2 (x=0.2-0.8).
FIG. 6 shows a star-shaped porous Zr prepared according to the present invention x Ti 1-x O 2 Transmission electron micrographs of (x=0.2-0.8).
FIG. 7 shows a precursor star-shaped BaZr prepared according to the present invention x Ti 1-x O 3 (x=0.2-0.8), the product star-shaped porous Zr x Ti 1-x O 2 (x=0.2-0.8) X-ray powder diffraction pattern and Zr x Ti 1-x O 2 Nitrogen adsorption and desorption curves of (3).
FIGS. 8 and 9 show a star-shaped porous Zr prepared according to the present invention x Ti 1-x O 2 (x=0.2-0.8) isothermal adsorption curves, adsorption kinetics curves, adsorption performance and cycle performance graphs of hexavalent chromium in aqueous solutions under different pH environments.
Detailed Description
The invention is described in further detail below in connection with examples. It should be noted that the present invention is not limited to these specific embodiments. Equivalent substitutions and modifications can be made by those skilled in the art without departing from the background and spirit of the invention, and the contents thereof are also included in the scope of the present invention.
Comparative example 1
The transition metal oxide ZrO was prepared by the conventional preparation method- -precipitation method 2 ZrOCl is firstly carried out 2 ·8H 2 O is dissolved in water, and then ammonia water is added dropwise to adjust the pH to 9, so that white precipitate is obtained. The precipitate was washed with deionized water several times and dried in an oven to give a white powder. Annealing the white powder at 400 ℃ for 4 hours to obtain ZrO 2 . The use of the catalyst for chromium (VI) ion adsorption can adsorb chromium (VI) from 2010ppb to 150ppb. It can be seen that this residual amount of adsorption is also much higher than the standard allowed for drinking water (50 ppb). Thus, zrO produced by conventional precipitation method 2 Does not have excellent adsorption performance.
Comparative example 2
The present example uses another conventional preparation method, sol-gel method, to prepare transition metal oxide ZrO 2 Zirconium n-butoxide is firstly dissolved in ethanol, polyethylene glycol is added, the mixture is stirred for 5 hours at 70 ℃ to form gel, and the gel is burnt into powder by a burning method. Annealing at 600 ℃ for 4 hours to obtain ZrO 2 . The catalyst is used for chromium (VI) ion adsorption, and can adsorb chromium (VI) from 2010ppb to 80ppb. It can be seen that this adsorption residue is above the standard allowed for drinking water (50 ppb), and the treated water still cannot be used as drinking water. Thus, zrO produced by conventional sol-gel method 2 Does not have excellent propertiesAdsorption performance.
Example 1
Firstly, preparing BaZrO with hollow spherical morphology by using a hydrothermal method 3 The precursor is prepared by reacting Ba (OH) 2 、ZrOCl 2 ·8H 2 O, KOH and H 2 O is fully stirred according to the mol ratio of 1:1:10:100 and then is placed in a hydrothermal device to react for 3 days at 150 ℃ to obtain the hollow BaZrO 3 . Hollow BaZrO precursor 3 Hydrochloric acid and water are mixed according to the mol ratio of 1:10:100, placed in a high-pressure reaction vessel, reacted for one day at 100 ℃, and then transferred to an oven at 150 ℃ for reaction for 3 hours. After this reaction, ba is completely dissolved out and converted into ZrO 2 . The product was dried in an oven at 70 ℃ by centrifugation and washing with deionized water. The product retains the hollow spherical characteristic of the precursor, and as can be seen from FIG. 1, the precursor BaZrO 3 And the product ZrO 2 Are hollow spheres. FIG. 2 shows ZrO 2 The characteristics of the hollow structure were confirmed by transmission electron microscopy. As can be seen from fig. 2, the hollow zirconia is composed of a plurality of ultrafine particles smaller than 1 nm stacked. It follows that Zr and O recrystallize in situ during etching to form very small nanoparticles. ZrO after Ba is dissolved out 2 The integral particles still maintain the morphology of the precursor, i.e., the hollow spherical structure. FIG. 3a shows a precursor of perovskite structure BaZrO 3 And ZrO of amorphous structure 2 Is an X-ray powder diffraction pattern of (c). FIG. 3b shows ZrO 2 The curve of nitrogen adsorption and desorption proves that a large number of mesopores exist in the nitrogen adsorption and desorption curve, and the specific surface area is up to 120m by using the BET method 2 g -1 . The zirconium dioxide was used to adsorb hexavalent chromium in purified water, and the adsorption performance thereof is shown in fig. 4. Hexavalent chromium can be adsorbed from 2ppm to less than 5ppb at different pH (2-7) taking no more than 1 minute. Distribution coefficient K d Up to > 10 5 . At the same time the material has a high adsorption capacity (60 mg g) -1 ) And excellent recycling performance. The chromium (VI) content of the water treated by the zirconium dioxide is far lower than the standard (less than 50 ppb) of drinking water regulated in China.
Example 2 of the embodiment
First, a hydrothermal method is used for preparing BaZr with star-shaped structure x Ti 1-x O 3 (x=0.2-0.8) precursor under conditions such that Ba (OH) 2 、ZrOCl 2 ·8H 2 O、 TiCl 4 And H 2 O is fully stirred according to the mol ratio of 1:x to (1-x) to 100 (x=0.2-0.8), and then is placed in a hydrothermal device to react for 1 day at 120 ℃ to obtain the BaZr x Ti 1-x O 3 . Precursor BaZr x Ti 1-x O 3 Hydrochloric acid and water are mixed according to the mol ratio of 1:12:100, placed in a high-pressure reaction vessel, reacted for one day at 110 ℃ and then transferred to an oven at 140 ℃ for 2 hours. After this reaction, ba is completely dissolved out and converted into Zr x Ti 1-x O 2 (x=0.2-0.8). The product was dried in an oven at 70 ℃ by centrifugation and washing with deionized water. Product Zr x Ti 1-x O 2 (x=0.2 to 0.8) has the same star shape as the precursor, and is confirmed by the scanning electron microscope of fig. 5. FIG. 6 shows Zr x Ti 1-x O 2 Transmission electron microscopy (x=0.2-0.8), from which it can be seen that this star-shaped Zr x Ti 1-x O 2 (x=0.2-0.8) is a combination of numerous ultra-fine particle packing of less than 1 nm, consistent with the phenomenon of example 1. It can be seen that the mechanism of the etching process is consistent with example 1. FIG. 7a shows a precursor of perovskite structure, baZr x Ti 1-x O 3 (x=0.2-0.8) and Zr of amorphous structure x Ti 1-x O 2 X-ray powder diffraction pattern of (x=0.2-0.8). FIG. 7b shows ZrO 2 The curve of nitrogen adsorption and desorption proves that a large number of micropores exist in the nitrogen adsorption and desorption catalyst, and the specific surface area of the nitrogen adsorption and desorption catalyst is up to 300m by using a BET method 2 g -1 . The material is used for purifying water to adsorb hexavalent chromium and pentavalent arsenic, and can adsorb chromium from 2ppm to less than 1ppb, and arsenic from 2ppm to less than 5ppb, and has partition coefficient K d Up to > 10 5 . It takes no more than 10 seconds and the material has excellent recycling properties, see in particular figures 8 and 9.
Example 3
Firstly, preparing BaZrO with truncated octahedral morphology by using a hydrothermal method 3 The precursor is prepared by reacting Ba (OH) 2 、ZrOCl 2 ·8H 2 O and H 2 O is fully stirred according to the mol ratio of 1:1:100 and then is placed in a hydrothermal device to react for 1 day at 130 ℃ to prepare the truncated octahedron BaZrO 3 . Precursor BaZrO 3 Hydrochloric acid and water are mixed according to the mol ratio of 1:10:100, placed in a high-pressure reaction vessel, reacted for one day at 110 ℃ and then transferred to a baking oven at 130 ℃ for 3 hours. After this reaction, ba is completely dissolved out and converted into truncated octahedral ZrO 2 . The product was dried in an oven at 70 ℃ by centrifugation and washing with deionized water. The course and mechanism of the preparation reaction are identical to those of example 1. X-ray powder diffraction showed that the zirconium dioxide had an amorphous phase. The zirconium dioxide is used for purifying water to adsorb hexavalent chromium, and can adsorb hexavalent chromium from high-concentration chromium (> 2 ppm) to below 4ppb under different pH environments, and the time is not more than 1 minute. Distribution coefficient K d Up to > 10 5 。
Example 4
K was prepared by high temperature solid phase method 2 CO 3 、TiO 2 Reacting for 10 hours at 850 ℃ according to the mol ratio of 1:1 to obtain the lamellar compound K 2 TiO 5 Will K 2 TiO 5 Salicylic acid and water were mixed in a molar ratio of 1:5:10, placed in a high pressure reaction vessel, reacted at 100℃for one day, and then transferred to a 200℃oven for 3 hours. The reaction product was washed with ethanol and water several times and dried to give a yellow product. The product is salicylic acid surface-modified TiO 2 . The TiO is then treated 2 As an adsorbent for lead (II) in water, it is possible to adsorb lead from 2000ppb down to 0.03 ppb. The residual values are far below the standards allowed for drinking water (< 10 ppb). Distribution coefficient K d Up to > 10 8 。
Example 5
K was prepared by high temperature solid phase method 2 CO 3 、TiO 2 Reacting for 10 hours at 850 ℃ according to the mol ratio of 2:1 to obtain KTiO 3 KTiO is taken 3 Mixing acrylic acid and water according to the mol ratio of 1:2:3, placing the mixture into a high-pressure reaction vessel, reacting for one day at 100 ℃, and transferring the mixture into a 200 ℃ oven for reacting for 3 hours. Washing the reaction product with ethanol and water for several times, and drying to obtain milky TiO product 2 . Uranium (UO) 2 ) Experiments of adsorption prove that the TiO 2 The method has excellent uranium adsorption performance, and can adsorb uranium from 2000ppb to 0.01ppb. Distribution coefficient K d Up to > 10 7 . The material can be used for extracting uranium from seawater (nuclear fission important material), and adsorbing and enriching extremely low-concentration uranium (< 3 ppb) in seawater. Can also be used for treating radioactivity (UO) 2 ) The polluted water can remove radioactive substances and also can extract, enrich and recycle uranium.
Example 6
Preparation of spherical SrMnO Using hydrothermal method 3 The precursor, nitric acid and water are mixed according to the mol ratio of 1:2:100, and are placed in a high-pressure reaction vessel to react for one day at 80 ℃, and then transferred to an oven at 120 ℃ to react for 5 hours. After this reaction, sr is totally dissolved out and converted into spherical porous MnO product 2 . The manganese dioxide can be used for purifying water to adsorb divalent cadmium, can be adsorbed from high concentration (> 2 ppm) to below 5ppb, and takes no more than 1 minute.
Example 7
Rod-like K is prepared by using high-temperature solid phase method 2 TiO 5 The precursor, acetic acid and water are mixed according to the mol ratio of 1:30:10, and are placed in a high-pressure reaction vessel to react for one day at 100 ℃, and then are transferred to an oven at 160 ℃ to react for 2 hours. After this reaction, the potassium is totally dissolved out and converted into product rod-shaped porous TiO 2 . The water used for purification adsorbs divalent lead, can adsorb from high concentration lead (> 2 ppm) to less than 0.5ppb, and takes no more than 5 minutes.
Example 8
Preparation of square SrFeO block by high temperature solid phase method 3 Precursor(s)The precursor and formic acid are mixed according to the mol ratio of 1:30, placed in a high-pressure reaction vessel, reacted for two days at 100 ℃ and then transferred to a baking oven at 130 ℃ for 2 hours. After this reaction, sr is totally dissolved out and converted into product square porous Fe 2 O 3 . The water used for purification adsorbs divalent lead, can adsorb from high-concentration lead (> 2 ppm) to less than 1ppb, and takes no more than 3 minutes.
Claims (8)
1. An application of a transition metal oxide adsorbent in thoroughly removing harmful ions in water, which is characterized in that:
1) The general formula of the transition metal oxide adsorbent is MxOy, wherein M is selected from one or more transition metal elements of Zr, ti, fe, mn, mo and W, x is more than or equal to 1 and less than or equal to 2, and y is more than or equal to 1 and less than or equal to 5; the surface is rich in hydroxyl, has strong affinity with harmful metal ions, is amorphous or low in crystalline phase, has various particle morphology and size, and has a large number of micro/nano hole structures;
2) The preparation method of the transition metal oxide adsorbent comprises the steps of preparing the multi-element composite oxide A by adopting a hydrothermal method or a high-temperature solid-phase method a M x O y The precursor, wherein A is alkali metal or alkaline earth metal element, M is one or more transition metal elements of Zr, ti, fe, mn, mo and W, and the shape and size can be regulated and controlled by regulating the content and the reaction temperature of different doping elements, so that spherical, polyhedral, star-shaped and hollow various structures are prepared; then mixing the precursor with inorganic acid or organic acid, and preparing transition metal oxide M by two-step heating method x O y : (I) Reacting the precursor at 60-100deg.C for 2-10 hr, and (II) reacting at 100-300deg.C for 2-10 hr; the target product can be obtained after cleaning, separating and drying, and the morphology of the target product is consistent with that of the precursor.
2. Use according to claim 1, characterized in that the harmful ions chromium (VI), lead (II), arsenic (V), cadmium (II), uranium (VI) ions in water can be adsorbed to drinking water levels; chromium (VI) can be adsorbed from 2010ppb to < 6ppb and lead (II) from 2000ppb to < 0.06ppbUranium (VI) adsorbs from 2000ppb to < 0.03ppb, arsenic (V) adsorbs from 1000ppb to < 10ppb, and cadmium (II) adsorbs from 2000ppb to < 1ppb; adsorption partition coefficient Kd value chromium (VI), arsenic (V) > 105ml g -1 Lead (II) and uranium (VI) > 108ml g -1 Meanwhile, the catalyst has the advantages of quick adsorption and good recycling performance.
3. Use according to claim 2, wherein the transition metal oxide adsorbent is capable of reaching adsorption equilibrium in 2 seconds to 10 minutes, is desorbed and recovered under certain conditions after adsorption of the deleterious metals, and is reusable for adsorption.
4. The use according to claim 1, wherein the transition metal oxide adsorbent has a hydroxyl oxygen content of 50% -80% in the peaks of X-ray photoelectron spectroscopy oxygen and a hydroxyl density of 72 hydroxyl groups per square nanometer, and the high density hydroxyl groups are proved to be a source of excellent adsorption properties and can form chelation with harmful ions.
5. The use according to claim 1, wherein the transition metal oxide adsorbent is amorphous or low crystalline phase X-ray powder diffraction results in no distinct diffraction peaks or low intensity diffraction peaks.
6. The use according to claim 1, wherein the transition metal oxide particles have various shapes and sizes, the shapes of the particles can be regulated to be spherical, polyhedral, star-shaped and hollow, and the sizes of the particles are 1 nanometer to 100 micrometers.
7. The use according to claim 1, wherein the transition metal oxide adsorbent has a plurality of micro/nano pore structures, and nitrogen adsorption and desorption experiments prove that a plurality of mesoporous or microporous structures exist, and the transition metal oxide adsorbent has a large specific surface area of 70-300m 2 g -1 。
8. The use according to claim 1, characterized in that the adsorption of trace amounts of harmful ions has the following advantages:
1) Microetching under acidic conditions promotes the internal cations and protons H of the precursor particles + Exchanging to form high-density inner surface hydroxyl, having strong adsorption force to harmful ions, and micro-etching to dissolve out alkali metal or alkaline earth metal in the precursor under acidic condition to obtain a large amount of protons H + Exchanging with alkali metal or alkaline earth metal to form hydroxyl on the inner surface, wherein the hydroxyl with high density forms chelation to harmful ions, has extremely strong adsorption force and can thoroughly remove the harmful ions;
2) The micro-etching hydrothermal reaction realizes accurate selective etching, and the micro-etching under acid selectively partially etches the precursor to realize accurate pore-forming, so that rich pore channel structures and high specific surface area are formed, the anchoring of harmful ions is enhanced, and the adsorption capacity is increased;
3) The morphology of the adsorbent is regulated and controlled through precursor induction, the morphology of the precursor is reserved for the transition metal oxide product formed by microetching, and the mass transfer process of adsorption is promoted and the specific surface area is increased through selecting the morphology favorable for adsorption.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201910614046.5A CN112206742B (en) | 2019-07-09 | 2019-07-09 | Porous oxide adsorption material for efficiently removing harmful ions in water |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201910614046.5A CN112206742B (en) | 2019-07-09 | 2019-07-09 | Porous oxide adsorption material for efficiently removing harmful ions in water |
Publications (2)
Publication Number | Publication Date |
---|---|
CN112206742A CN112206742A (en) | 2021-01-12 |
CN112206742B true CN112206742B (en) | 2023-09-15 |
Family
ID=74048352
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201910614046.5A Active CN112206742B (en) | 2019-07-09 | 2019-07-09 | Porous oxide adsorption material for efficiently removing harmful ions in water |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN112206742B (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113351153B (en) * | 2021-05-24 | 2022-08-09 | 桂林理工大学 | MgFe-LDO-MnO 2 Preparation method and application of composite material |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102068957A (en) * | 2009-11-20 | 2011-05-25 | 中国科学院金属研究所 | Zirconium-based arsenic removing material and preparation method and application thereof |
CN102249350A (en) * | 2011-05-13 | 2011-11-23 | 北京大学 | Single-phase multi-ferric material and preparation method thereof |
CN102838162A (en) * | 2011-06-21 | 2012-12-26 | 中国科学院过程工程研究所 | Porous titanium dioxide hollow sphere, its preparation and method for adsorbing Cr(VI) |
CN105289543A (en) * | 2015-11-18 | 2016-02-03 | 南京大学 | Nanometer-hydrous zirconium oxide-loading composite hydrogel having carboxyl and hydroxyl, preparation and applications thereof |
CN108147453A (en) * | 2017-12-28 | 2018-06-12 | 苏州大学 | A kind of Novel Titanium dioxide microparticle material and preparation method thereof, the application in field of environment protection |
-
2019
- 2019-07-09 CN CN201910614046.5A patent/CN112206742B/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102068957A (en) * | 2009-11-20 | 2011-05-25 | 中国科学院金属研究所 | Zirconium-based arsenic removing material and preparation method and application thereof |
CN102249350A (en) * | 2011-05-13 | 2011-11-23 | 北京大学 | Single-phase multi-ferric material and preparation method thereof |
CN102838162A (en) * | 2011-06-21 | 2012-12-26 | 中国科学院过程工程研究所 | Porous titanium dioxide hollow sphere, its preparation and method for adsorbing Cr(VI) |
CN105289543A (en) * | 2015-11-18 | 2016-02-03 | 南京大学 | Nanometer-hydrous zirconium oxide-loading composite hydrogel having carboxyl and hydroxyl, preparation and applications thereof |
CN108147453A (en) * | 2017-12-28 | 2018-06-12 | 苏州大学 | A kind of Novel Titanium dioxide microparticle material and preparation method thereof, the application in field of environment protection |
Non-Patent Citations (1)
Title |
---|
A Facile Top-Down Method to Fabricate Transition Metal Compounds with Fascinating Structures from Etching method;Wujie Dong等;《Gen. Chem.》;20181231;第4卷;第170022-1至170022-7页 * |
Also Published As
Publication number | Publication date |
---|---|
CN112206742A (en) | 2021-01-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
Husnain et al. | Recent trends of MnO 2-derived adsorbents for water treatment: a review | |
Li et al. | Versatile inorganic-organic hybrid WO x-ethylenediamine nanowires: Synthesis, mechanism and application in heavy metal ion adsorption and catalysis | |
Zhou et al. | Novel hollow microspheres of hierarchical zinc–aluminum layered double hydroxides and their enhanced adsorption capacity for phosphate in water | |
Nakarmi et al. | Benign zinc oxide betaine-modified biochar nanocomposites for phosphate removal from aqueous solutions | |
Song et al. | Interaction of U (VI) with ternary layered double hydroxides by combined batch experiments and spectroscopy study | |
Sun et al. | Biotemplated fabrication of a 3D hierarchical structure of magnetic ZnFe2O4/MgAl-LDH for efficient elimination of dye from water | |
CN114425340B (en) | Preparation of biochar modified cobalt-iron bimetallic composite catalyst and application of biochar modified cobalt-iron bimetallic composite catalyst in catalytic degradation of tetracycline | |
Yang et al. | Exfoliation of a two-dimensional cationic inorganic network as a new paradigm for high-capacity Cr VI-anion capture | |
Cao et al. | Ca–La layered double hydroxide (LDH) for selective and efficient removal of phosphate from wastewater | |
JP5352853B1 (en) | Method of treating radioactive Cs contaminated water | |
CN113145062B (en) | Preparation method of magnetic adsorption material based on Prussian blue and hydrotalcite | |
Ryu et al. | Mechanochemical synthesis of silica-lithium manganese oxide composite for the efficient recovery of lithium ions from seawater | |
Uddin et al. | Adsorptive removal of pollutants from water using magnesium ferrite nanoadsorbent: a promising future material for water purification | |
JP5774619B2 (en) | Production of low BET trimanganese tetraoxide and particle size control method, and trimanganese tetraoxide | |
Wang et al. | Shell biomass material supported nano-zero valent iron to remove Pb2+ and Cd2+ in water | |
CN112206742B (en) | Porous oxide adsorption material for efficiently removing harmful ions in water | |
Sahu et al. | Nanoceria-loaded tea waste as bio-sorbent for Cr (VI) removal | |
Guo et al. | Removal of Cu (II) from aqueous solution by iron vanadate: equilibrium and kinetics studies | |
Zhang et al. | Activation of ozone by CoFe-LDO-BC heterogeneous catalyst for efficient mineralization of methylene blue: The role of oxygen vacancies and acidic sites | |
Amarray et al. | Reduction of cadmium content in 29% and 54% P2O5 phosphoric acid by manganese oxide material birnessite-type Na-MnO2 | |
Xiao et al. | The co-adsorption of Cu 2+ and Zn 2+ with adsorption sites surface-lattice reforming on calcined layered double hydroxides | |
CN108514888B (en) | Preparation of polyacid intercalation hydrotalcite photocatalytic material and photocatalytic fuel oil deep desulfurization system | |
Yang et al. | Catalytic ozonation performance and surface property of supported Fe 3 O 4 catalysts dispersions | |
CN102688665B (en) | Method for comprehensively treating Klaus tail gas and producing manganese sulfate | |
Hosny et al. | Utilization of cross-linked chitosan/ACTF biocomposite for softening hard water: optimization by adsorption modeling |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PB01 | Publication | ||
PB01 | Publication | ||
SE01 | Entry into force of request for substantive examination | ||
SE01 | Entry into force of request for substantive examination | ||
GR01 | Patent grant | ||
GR01 | Patent grant |