CN113578256A - Iron-magnesium hydrotalcite @ bentonite composite material and preparation method and application thereof - Google Patents

Iron-magnesium hydrotalcite @ bentonite composite material and preparation method and application thereof Download PDF

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CN113578256A
CN113578256A CN202110656160.1A CN202110656160A CN113578256A CN 113578256 A CN113578256 A CN 113578256A CN 202110656160 A CN202110656160 A CN 202110656160A CN 113578256 A CN113578256 A CN 113578256A
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iron
composite material
magnesium
bentonite
heavy metal
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袁兴中
管弦
赵燕兰
柏菁
李英
陈浩云
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Hunan University
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    • 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
    • B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
    • B01J20/12—Naturally occurring clays or bleaching earth
    • B—PERFORMING OPERATIONS; TRANSPORTING
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    • 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
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    • 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
    • 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
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    • B01J20/28061—Surface area, e.g. B.E.T specific surface area being in the range 100-500 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
    • C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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Abstract

The invention discloses an iron-magnesium hydrotalcite @ bentonite composite material and a preparation method and application thereof. The preparation method comprises the following steps: and dropwise adding a mixed solution containing at least one of sodium bicarbonate, sodium carbonate and sodium hydroxide into the mixed solution of magnesium salt, ferric salt and bentonite, carrying out coprecipitation reaction until the pH value of the solution is 9.5-10, aging, washing, drying, grinding and sieving to obtain the composite material. The iron-magnesium hydrotalcite @ bentonite composite material has the advantages of low cost, large adsorption capacity, good stability and the like, is a novel green, environment-friendly and economic adsorbent, can be widely used for treating heavy metal wastewater, can realize efficient and thorough removal of heavy metals in the wastewater, and has high use value and good application prospect.

Description

Iron-magnesium hydrotalcite @ bentonite composite material and preparation method and application thereof
Technical Field
The invention belongs to the technical field of environment-friendly adsorption materials, and relates to an iron-magnesium hydrotalcite @ bentonite composite material, and a preparation method and application thereof.
Background
Heavy metals have strong chemical stability and biological degradability, cannot be degraded through a natural biological process, can be stored in water for a long time, can damage the nervous system and tissues and organs of organisms, and continuously cause serious environmental and health problems. At present, in order to reduce the pollution of heavy metal pollutants to the environment, technologies such as photocatalytic degradation, membrane filtration, flocculation and precipitation, electrochemical treatment and adsorption are applied to the treatment of heavy metal pollution, wherein the adsorption method for treating the heavy metal polluted water body is emphasized due to the characteristics of simple operation, low investment, good quality of treated effluent water and the like, but most of adsorbents have the defects of low adsorption capacity, high cost, poor stability and the like, so that the existing adsorbents cannot be widely applied to the treatment of the heavy metal polluted water body, and therefore, more efficient, environment-friendly and low-cost adsorbent materials need to be developed.
Bentonite is often used in the treatment process of polluted water, and is a non-metal mineral product taking montmorillonite as a main mineral component, and the montmorillonite structure is a 2:1 type crystal structure consisting of two silicon-oxygen tetrahedrons and a layer of aluminum-oxygen octahedron, and shows a certain adsorption capacity on a plurality of pollutants. However, according to previous studies, the adsorption of heavy metals by bentonite is mainly performed by cation exchange, and the adsorption capacity is poor due to few adsorption sites, so that effective removal of heavy metals in water is difficult to achieve. In addition, during the practical research process of the inventor of the present application, it is also found that: when bentonite and hydrotalcite materials (such as magnesium aluminum hydrotalcite and cobalt aluminum hydrotalcite) are compounded, the obtained composite material still has the defects of low adsorption capacity, poor stability and the like, and simultaneously has the problems of complex preparation process, higher cost and the like. Therefore, the obtained composite adsorption material has the advantages of low cost, large adsorption capacity and good stability, and the matched preparation method with simple process, convenient operation, mild reaction condition, low cost, high production efficiency, short production period and high product yield has very important significance for removing heavy metal ions in water with low cost, high efficiency and environmental protection.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides the iron-magnesium hydrotalcite @ bentonite composite material with low cost, large adsorption capacity and good stability, and also provides a preparation method of the iron-magnesium hydrotalcite @ bentonite composite material with simple process, convenient operation, mild reaction conditions, low cost, high production efficiency, short production period and high product yield, and application of the iron-magnesium hydrotalcite @ bentonite composite material in treatment of heavy metal wastewater.
In order to solve the technical problems, the invention adopts the technical scheme that:
the iron-magnesium hydrotalcite @ bentonite composite material comprises bentonite and iron-magnesium hydrotalcite, wherein the iron-magnesium hydrotalcite is loaded on the surface of the bentonite.
In the iron-magnesium hydrotalcite @ bentonite composite material, the iron-magnesium hydrotalcite @ bentonite composite material is further improved to be in a petal-shaped structure; the iron-magnesium hydrotalcite is of a sheet structure; the specific surface area of the iron-magnesium hydrotalcite @ bentonite composite material is 154m2/g。
As a general technical concept, the invention also provides a preparation method of the iron-magnesium hydrotalcite @ bentonite composite material, which comprises the following steps:
s1, mixing the magnesium salt, the ferric iron salt, the bentonite and water to obtain a mixed solution;
s2, dropwise adding a mixed solution containing at least one of sodium bicarbonate, sodium carbonate and sodium hydroxide into the mixed solution obtained in the step S1 for coprecipitation reaction until the pH value of the solution is 9.5-10;
s3, aging, washing, drying, grinding and sieving a product obtained after the coprecipitation reaction in the step S2 to obtain the iron-magnesium hydrotalcite @ bentonite composite material.
In a further improvement of the above preparation method, in step S1, the ratio of bentonite, magnesium salt and ferric salt is 1 g-10 g: 0.04 mol.
In a further improvement of the above preparation method, in step S1, the ratio of bentonite, magnesium salt and ferric salt is 1 g: 0.04 mol.
In a further improvement of the above preparation method, in step S1, the magnesium salt is at least one of magnesium nitrate, magnesium sulfate and magnesium chloride; the ferric salt is at least one of ferric nitrate, ferric chloride and ferric sulfate.
In a further improvement of the above preparation method, in step S2, the concentrations of sodium bicarbonate, sodium carbonate and sodium hydroxide contained in the mixed solution are all 0.5 mol/L; the end point pH of the precipitation reaction was 10.
As a general technical concept, the invention also provides an application of the iron-magnesium hydrotalcite and bentonite composite material or the iron-magnesium hydrotalcite and bentonite composite material prepared by the preparation method in treatment of heavy metal wastewater.
The application is further improved, and comprises the following steps: mixing the iron-magnesium hydrotalcite @ bentonite composite material with heavy metal wastewater to carry out oscillation adsorption, thereby finishing the treatment of the heavy metal wastewater; the iron-magnesium hydrotalcite and bentonite composite material is added in an amount of 0.25g per liter of heavy metal wastewater.
In the above application, further improved, the heavy metal in the heavy metal wastewater is at least one of Pb and Cd; the concentration of Pb in the heavy metal wastewater is less than or equal to 350 mg/L; the concentration of Cd in the heavy metal wastewater is less than or equal to 175 mg/L; the pH value of the heavy metal wastewater is 3-7; the rotation speed of the oscillation adsorption is 150-200 rpm; the temperature of the oscillation adsorption is 25-45 ℃; the time of the oscillation adsorption is 5min to 1440 min.
Compared with the prior art, the invention has the advantages that:
(1) the invention provides an iron-magnesium hydrotalcite @ bentonite composite material, bentonite and iron-magnesium hydrotalcite, wherein the iron-magnesium hydrotalcite is loaded on the surface of the bentonite. According to the invention, the bentonite has the advantages of stability, low price, strong adsorption capacity and the like, and the iron-magnesium hydrotalcite has the advantages of relative easiness in synthesis, lower price, strong adsorption capacity and the like, so that the composite material with low price, easiness in synthesis, good stability and strong adsorption capacity can be obtained by loading the iron-magnesium hydrotalcite on the surface of the bentonite, and meanwhile, the specific surface area of the composite material can be greatly increased, the number of active sites is more, and the adsorption capacity is greatly increased by loading the iron-magnesium hydrotalcite on the bentonite. Compared with the conventional adsorbent material, the iron-magnesium hydrotalcite @ bentonite composite material has the advantages of low cost, large adsorption capacity, good stability and the like, is a novel green, environment-friendly and economic adsorbent, can be widely used for treating heavy metal wastewater, can realize efficient and thorough removal of heavy metals in the wastewater, and has high use value and good application prospect.
(2) The iron-magnesium hydrotalcite @ bentonite composite material has rich petal layered structures, can provide more adsorption sites in the reaction process, and further improves the adsorption effect.
(3) The invention also provides a preparation method of the iron-magnesium hydrotalcite @ bentonite composite material, which takes magnesium salt, ferric salt and bentonite as raw materials, and leads the magnesium salt and the ferric salt to generate coprecipitation reaction under the action of alkaline conditions (dropwise adding mixed solution containing at least one substance of sodium bicarbonate, sodium carbonate and sodium hydroxide) to generate the iron-magnesium hydrotalcite and load the iron-magnesium hydrotalcite on the surface of the bentonite, thereby obtaining the iron-magnesium hydrotalcite @ bentonite composite material with large specific surface area, more active sites, good adsorption performance and good stability. Meanwhile, the raw materials adopted in the preparation method are wide in source and low in price, and the standard of modern scientific technology which is green, environment-friendly, high in quality and low in price is better met. Compared with other conventional methods, the preparation method has the advantages of simple process, mild reaction conditions, convenient operation, cleanness, no pollution and the like, is suitable for large-scale preparation, and is convenient for industrial utilization.
(4) In the preparation method of the iron-magnesium hydrotalcite @ bentonite composite material, the proportion of the usage amount of the bentonite, the magnesium salt and the ferric salt is optimized, so that the load stability of the iron-magnesium hydrotalcite can be further improved, the composite material can be ensured to have a larger specific surface area and more adsorption sites, and the composite material can be ensured to adsorb target pollutants stably, efficiently and in high capacity.
(5) The invention also provides the application of the iron-magnesium hydrotalcite and bentonite composite material in heavy metal wastewater treatment, the iron-magnesium hydrotalcite and bentonite composite material is used for carrying out oscillation adsorption treatment on the heavy metal wastewater, so that the heavy metal in the wastewater can be efficiently and thoroughly removed, the method has the advantages of simple process, low cost, good removal effect, strong anti-infection capability and the like, can be widely used for treating the heavy metal wastewater, and has very important significance for removing the heavy metal ions in the water body with low cost, high efficiency and environmental protection.
(6) In the application method, the magnesium hydrotalcite @ bentonite composite material used in the method can show higher adsorbability when adsorbing heavy metals in the presence of various cations, and has wide application prospect in the aspect of adsorption of environmental heavy metal pollutants.
(7) In the application method, the magnesium hydrotalcite @ bentonite composite material can show a good adsorption effect when the pH range is 3-7, and heavy metal ions can generate precipitates when the pH is more than 7, so that the magnesium hydrotalcite @ bentonite composite material has a wide application prospect in the aspect of adsorption of heavy metal pollution to the environment.
(8) In the application method of the invention, the used magnesium hydrotalcite @ bentonite composite material still can show higher adsorbability in actual water bodies (tap water, river water and lake water).
Drawings
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.
FIG. 1 is an SEM image of an iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in example 1 of the present invention.
FIG. 2 is a TEM image of an iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in example 1 of the present invention.
FIG. 3 is an element distribution diagram of an iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in example 1 of the present invention.
FIG. 4 is an XRD diagram of an iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in example 1 of the present invention.
FIG. 5 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1), magnesium-aluminum hydrotalcite @ bentonite composite material (MgAl-LDH @ B-1), and cobalt-aluminum hydrotalcite @ bentonite composite material (CoAl-LDH @ B-1) on heavy metals of lead and cadmium in wastewater in example 6 of the present invention.
FIG. 6 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite materials (FeMg-LDH @ B-1, FeMg-LDH @ B-2, FeMg-LDH @ B-4, FeMg-LDH @ B-6, FeMg-LDH @ B-10), iron-magnesium hydrotalcite (FeMg-LDH), and bentonite (Ben) on heavy metals of lead and cadmium in wastewater in example 6 of the present invention.
FIG. 7 is a graph showing the adsorption effect of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in wastewater under different pH conditions in example 7 of the present invention.
FIG. 8 is a graph showing the zeta potential changes of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) in the heavy metal wastewater with different pH values in example 7 of the present invention.
FIG. 9 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in wastewater under different temperature conditions in example 8 of the present invention.
FIG. 10 is a graph showing the adsorption effect of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in wastewater under different time conditions in example 9 of the present invention.
FIG. 11 is a graph showing the adsorption effect of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metal lead in wastewater with different concentrations in example 10 of the present invention.
FIG. 12 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metal cadmium in wastewater with different concentrations in example 10 of the present invention.
FIG. 13 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in wastewater under different coexisting ion conditions in example 11 of the present invention.
FIG. 14 is a graph showing the adsorption effect of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in different practical water bodies in example 13 of the present invention.
FIG. 15 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in mixed wastewater in example 13 of the present invention.
Detailed Description
The invention is further described below with reference to the drawings and specific preferred embodiments of the description, without thereby limiting the scope of protection of the invention.
In the following examples of the present invention, unless otherwise specified, materials and instruments used are commercially available, processes used are conventional, apparatuses used are conventional, and the obtained data are average values of three or more repeated experiments.
Example 1
The iron-magnesium hydrotalcite @ bentonite composite material comprises bentonite and iron-magnesium hydrotalcite, wherein the iron-magnesium hydrotalcite is loaded on the surface of the bentonite to form the composite material with a petal-shaped structure.
In this example, the iron-magnesium hydrotalcite is a sheet structure.
In this example, the specific surface area of the iron-magnesium hydrotalcite @ bentonite composite material is 154m2/g。
The preparation method of the iron-magnesium hydrotalcite @ bentonite composite material in the embodiment of the invention is characterized by comprising the following steps:
s1, adding 0.04mol of Mg (NO) at room temperature3)2·6H2O, 0.04mol of Fe (NO)3)3·9H2O and 1g of bentonite, and performing ultrasonic treatment to uniformly mix the O and the bentonite in deionized water to obtain a mixed solution.
S2, under the condition of magnetic stirring, dropwise adding a mixed solution of sodium carbonate and sodium hydroxide (0.5 mol/L of both sodium carbonate and sodium hydroxide in the mixed solution) into the mixed solution obtained in the step S1 for coprecipitation reaction until the pH value of the solution is 10.0, and stopping stirring.
S3, aging the product obtained after the coprecipitation reaction in the step S2 at room temperature, washing the aged product with deionized water until the pH value of the washing liquid is neutral, drying in a blast drying oven at 70 ℃, grinding and sieving to obtain the iron-magnesium hydrotalcite @ bentonite composite material which is recorded as FeMg-LDH @ B-1.
Example 2
The preparation method of the iron-magnesium hydrotalcite @ bentonite composite material is basically the same as that of the example 1, and the difference is only that: in example 2, the amount of bentonite used was 2 g.
The iron-magnesium hydrotalcite @ bentonite composite material prepared in example 2 is denoted as FeMg-LDH @ B-2.
Example 3
The preparation method of the iron-magnesium hydrotalcite @ bentonite composite material is basically the same as that of the example 1, and the difference is only that: in example 3, the amount of bentonite used was 4 g.
The iron-magnesium hydrotalcite @ bentonite composite material prepared in example 3 is noted as FeMg-LDH @ B-4.
Example 4
The preparation method of the iron-magnesium hydrotalcite @ bentonite composite material is basically the same as that of the example 1, and the difference is only that: in example 4, the amount of bentonite used was 6 g.
The iron-magnesium hydrotalcite @ bentonite composite material prepared in example 4 is noted as FeMg-LDH @ B-6.
Example 5
The preparation method of the iron-magnesium hydrotalcite @ bentonite composite material is basically the same as that of the example 1, and the difference is only that: in example 5, the amount of bentonite used was 10 g.
The iron-magnesium hydrotalcite @ bentonite composite material prepared in example 5 is noted as FeMg-LDH @ B-10.
Comparative example 1
A method for preparing iron-magnesium hydrotalcite, which is substantially the same as that in example 1, except that: in comparative example 1 no bentonite was added.
The iron-magnesium hydrotalcite prepared in comparative example 1 had a specific surface area of 66m2And/g, recorded as FeMg-LDH.
Comparative example 2
The preparation method of the magnesium aluminum hydrotalcite @ bentonite composite material is basically the same as that of the example 1, and the difference is only that: in comparative example 2, Al (NO) was used3)3·9H2O instead of Fe (NO)3)3·9H2O。
The Mg-Al hydrotalcite @ bentonite composite material prepared in the comparative example 2 is marked as MgAl-LDH @ B-1.
Comparative example 3
The preparation method of the cobalt-aluminum hydrotalcite @ bentonite composite material is basically the same as that of the example 1, and the difference is only that: in comparative example 3, Co (NO) was used3)2·6H2O instead of Mg (NO)3)2·6H2O，Al(NO3)3·9H2O instead of Fe (NO)3)3·9H2O。
The cobalt aluminum hydrotalcite @ bentonite composite material prepared in comparative example 3 is noted as CoAl-LDH @ B-1.
FIG. 1 is an SEM image of an iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in example 1 of the present invention. As can be seen from fig. 1, the iron-magnesium hydrotalcite @ bentonite composite material of the present invention has an obvious petal-shaped structure, which provides more adsorption sites during the adsorption process, thereby improving the adsorption capacity.
FIG. 2 is a TEM image of an iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in example 1 of the present invention. FIG. 3 is an element distribution diagram of an iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in example 1 of the present invention. As can be seen from fig. 2, in the iron-magnesium hydrotalcite @ bentonite composite material, bentonite is in an irregular shape, and iron-magnesium hydrotalcite is in a sheet shape, and as can be seen from the element distribution in fig. 3, iron-magnesium hydrotalcite is loaded on bentonite.
FIG. 4 is an XRD diagram of an iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in example 1 of the present invention. As can be seen from fig. 4, the peaks of the iron-magnesium hydrotalcite and bentonite composite material correspond to the characteristic peaks of the iron-magnesium hydrotalcite and bentonite, which indicates that the main component phase of the iron-magnesium hydrotalcite and bentonite composite material is iron-magnesium hydrotalcite and bentonite.
Example 6
An application of an iron-magnesium hydrotalcite @ bentonite composite material in treatment of heavy metal wastewater, specifically, the iron-magnesium hydrotalcite @ bentonite composite material prepared in examples 1-5 is used for respectively treating heavy metal lead wastewater and heavy metal cadmium wastewater, and the method comprises the following steps:
heavy metal lead (Pb) wastewater: taking the iron-magnesium hydrotalcite @ bentonite composite materials (FeMg-LDH @ B-1, FeMg-LDH @ B-2, FeMg-LDH @ B-4, FeMg-LDH @ B-6 and FeMg-LDH @ B-10) prepared in examples 1-5, the iron-magnesium hydrotalcite (FeMg-LDH) prepared in comparative example 1, the magnesium-aluminum hydrotalcite @ bentonite composite material (MgAl-LDH @ B-1) prepared in comparative example 2, the cobalt-aluminum hydrotalcite @ bentonite composite material (CoAl-LDH B-1) prepared in comparative example 3 and the bentonite (Ben, purchased from the market), respectively adding 5mg of the iron-magnesium hydrotalcite @ bentonite composite materials into 20mL of heavy metal lead wastewater (the pH value of the wastewater is 5) with the concentration of 300mg/L, placing the mixture in a constant temperature water bath kettle with the temperature of 25 ℃ and the rpm of 150 to perform oscillation adsorption for 24 hours, and finishing the treatment of the heavy metal lead wastewater.
Heavy metal cadmium (Cd) wastewater: taking the iron-magnesium hydrotalcite @ bentonite composite materials (FeMg-LDH @ B-1, FeMg-LDH @ B-2, FeMg-LDH @ B-4, FeMg-LDH @ B-6 and FeMg-LDH @ B-10) prepared in examples 1-5, the iron-magnesium hydrotalcite (FeMg-LDH) prepared in comparative example 1, the magnesium-aluminum hydrotalcite @ bentonite composite material (MgAl-LDH @ B-1) prepared in comparative example 2, the cobalt-aluminum hydrotalcite @ bentonite composite material (CoAl-LDH B-1) prepared in comparative example 3 and the bentonite (Ben), respectively adding 5mg of the iron-magnesium hydrotalcite @ bentonite composite materials into 20mL of heavy metal cadmium wastewater (the pH value of the wastewater is 5) with the concentration of 150mg/L, placing the wastewater in a constant temperature water bath kettle with the temperature of 25 ℃ and the rpm of 150 to perform oscillation adsorption for 24 hours, thereby finishing the treatment of the heavy metal cadmium wastewater.
After the oscillating adsorption is completed, 10mL of the treated solution is filtered through a 0.45-micrometer water-based filter membrane, the content of heavy metals in each filtrate is measured by using an inductively coupled plasma emission spectrometer (ICP-OES), and the adsorption amount of the heavy metals by different materials is calculated, and the results are shown in FIGS. 5 and 6.
FIG. 5 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1), magnesium-aluminum hydrotalcite @ bentonite composite material (MgAl-LDH @ B-1), and cobalt-aluminum hydrotalcite @ bentonite composite material (CoAl-LDH @ B-1) on heavy metals of lead and cadmium in wastewater in example 6 of the present invention. As can be seen from FIG. 5, the adsorption capacity of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) to heavy metal lead and cadmium in wastewater is 1088mg/g and 428.38mg/g respectively, the adsorption capacity of the magnesium-aluminum hydrotalcite @ bentonite composite material (MgAl-LDH @ B-1) to heavy metal lead and cadmium in wastewater is 466mg/g and 147.87mg/g respectively, the adsorption capacity of the cobalt-aluminum hydrotalcite @ bentonite composite material (CoAl-LDH @ B-1) to heavy metal lead and cadmium in wastewater is 305mg/g and 114mg/g respectively, and the adsorption effect of the iron-magnesium hydrotalcite composite material (FeMg-LDH @ B-1) to heavy metal lead and cadmium in wastewater is obviously better than that of the magnesium-aluminum hydrotalcite @ bentonite composite material (MgAl-LDH @ B-1) and the cobalt-aluminum hydrotalcite @ bentonite composite material (CoAl-LDH @ B-1), the iron-magnesium hydrotalcite @ bentonite composite material has more excellent adsorption performance.
FIG. 6 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite materials (FeMg-LDH @ B-1, FeMg-LDH @ B-2, FeMg-LDH @ B-4, FeMg-LDH @ B-6, FeMg-LDH @ B-10), iron-magnesium hydrotalcite (FeMg-LDH), and bentonite (Ben) on heavy metals of lead and cadmium in wastewater in example 6 of the present invention. As can be seen from FIG. 6, compared with bentonite (Ben), the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1, FeMg-LDH @ B-2, FeMg-LDH @ B-4, FeMg-LDH @ B-6 and FeMg-LDH @ B-10) has a significantly higher adsorption capacity for heavy metals of lead and cadmium in wastewater, wherein the adsorption capacity for Pb is 5.2-7.9 times that of bentonite, and the adsorption capacity for Cd is 3.8-9.8 times that of bentonite. Meanwhile, as can be seen from fig. 6, in the iron-magnesium hydrotalcite @ bentonite composite material of the present invention, the adsorption effect of FeMg-LDH @ B-1 on Pb is 1.6 times that of iron-magnesium hydrotalcite, and the adsorption capacity on Cd is 1.2 times that of iron-magnesium hydrotalcite, which has the best adsorption performance, however, as the addition amount of bentonite increases, the adsorption capacity of the obtained iron-magnesium hydrotalcite @ bentonite composite material gradually decreases because: as the addition amount of the bentonite is increased, the loadable sites of the bentonite are reduced, and the composite material cannot be formed, so that the adsorption amount is reduced.
Example 7
An application of an iron-magnesium hydrotalcite @ bentonite composite material in treatment of heavy metal wastewater, specifically, the iron-magnesium hydrotalcite @ bentonite composite material prepared in example 1 is used for respectively treating heavy metal lead wastewater and heavy metal cadmium wastewater, and the method comprises the following steps:
heavy metal lead (Pb) wastewater: 5 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1 are taken, 5mg of each part is respectively added into heavy metal lead wastewater (the volume is 20mL, the Pb concentration is 300mg/L) with the pH values of 3, 4, 5, 6 and 7, and the heavy metal lead wastewater is placed in a constant temperature water bath kettle with the temperature of 25 ℃ and the rpm of 150 for oscillation adsorption for 24 hours, so that the treatment of the heavy metal lead wastewater is completed.
Heavy metal cadmium (Cd) wastewater: 5 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1 are taken, 5mg of each part is respectively added into heavy metal cadmium wastewater (the volume is 20mL, the Cd concentration is 150mg/L) with the pH values of 3, 4, 5, 6 and 7, and the heavy metal cadmium wastewater is placed in a constant temperature water bath kettle at the temperature of 25 ℃ and the rpm of 150 for oscillation adsorption for 24 hours, so that the treatment of the heavy metal cadmium wastewater is completed.
After the oscillating adsorption is completed, 10mL of the treated solution is filtered through a 0.45-micrometer water-based filter membrane, the content of heavy metal in each filtrate is measured by using an inductively coupled plasma emission spectrometer (ICP-OES), and the adsorption capacity of the iron-magnesium hydrotalcite @ bentonite composite material to the heavy metal under different pH conditions is calculated, and the result is shown in FIG. 7.
FIG. 7 is a graph showing the adsorption effect of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in wastewater under different pH conditions in example 7 of the present invention. FIG. 8 is a graph showing the zeta potential changes of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) in the heavy metal wastewater with different pH values in example 7 of the present invention. As can be seen from FIG. 7, the pH range of the adsorption system constructed by the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) is relatively wide and is 3-7, and heavy metal ions can be precipitated under alkaline conditions. When the pH drops below 3, the material will partially decompose. When the pH is 3 to 7, the adsorption effect is improved as the pH is increased. Referring to fig. 8, it can be seen that when the pH is lower than 3, the material has a positive charge, H + will compete with Pb and Cd for adsorption, when the pH is 4-6, the material has a negative charge, Pb adsorption is enhanced, the adsorption amount is gradually increased, and when the pH is 7, Pb precipitates, so that the Pb content in the pollutants is greatly reduced.
Example 8
An application of an iron-magnesium hydrotalcite @ bentonite composite material in treatment of heavy metal wastewater, specifically, the iron-magnesium hydrotalcite @ bentonite composite material prepared in example 1 is used for respectively treating heavy metal lead wastewater and heavy metal cadmium wastewater, and the method comprises the following steps:
heavy metal lead (Pb) wastewater: 3 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1, 5mg of each part, are respectively added into 20mL of heavy metal lead wastewater (the pH value of the wastewater is 5) with the Pb concentration of 300mg/L, the wastewater is placed in a constant-temperature water bath kettle at the temperature of 25 ℃, 35 ℃ and 45 ℃, and the oscillating adsorption is carried out for 24 hours at the rpm of 150, so that the treatment of the heavy metal lead wastewater is completed.
Heavy metal cadmium (Cd) wastewater: 3 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1 are taken, 5mg of each part is respectively added into 20mL of heavy metal cadmium wastewater (the pH value of the wastewater is 5) with Cd concentration of 150mg/L, the wastewater is placed in a constant temperature water bath kettle at 25 ℃, 35 ℃ and 45 ℃, and the oscillating adsorption is carried out for 24 hours at 150rpm, so that the treatment of the heavy metal cadmium wastewater is completed.
After the oscillating adsorption is completed, 10mL of the treated solution is filtered through a 0.45-micrometer water-based filter membrane, the content of heavy metal in each filtrate is measured by using an inductively coupled plasma emission spectrometer (ICP-OES), and the adsorption capacity of the iron-magnesium hydrotalcite @ bentonite composite material to the heavy metal under different temperature conditions is calculated, and the result is shown in FIG. 9.
FIG. 9 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in wastewater under different temperature conditions in example 8 of the present invention. As can be seen from fig. 9, the adsorption amount of the iron-magnesium hydrotalcite @ bentonite composite material to the pollutants is increased with the increase of the temperature, which indicates that the adsorption is an endothermic reaction.
Example 9
An application of an iron-magnesium hydrotalcite @ bentonite composite material in treatment of heavy metal wastewater, specifically, the iron-magnesium hydrotalcite @ bentonite composite material prepared in example 1 is used for respectively treating heavy metal lead wastewater and heavy metal cadmium wastewater, and the method comprises the following steps:
heavy metal lead (Pb) wastewater: taking 5mg of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1, respectively adding the 5mg of the iron-magnesium hydrotalcite @ bentonite composite material into 20mL of heavy metal lead wastewater with the concentration of 300mg/L (the pH value of the wastewater is 5), placing the wastewater in a constant temperature water bath kettle at 25 ℃ and 150rpm, and carrying out oscillation adsorption for 5min to 1440min to complete the treatment of the heavy metal lead wastewater.
Heavy metal cadmium (Cd) wastewater: taking 5mg of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1, respectively adding the 5mg of the iron-magnesium hydrotalcite @ bentonite composite material into 20mL of heavy metal cadmium wastewater with the concentration of 150mg/L (the pH value of the wastewater is 5), placing the wastewater in a constant temperature water bath kettle at 25 ℃ and 150rpm, and carrying out oscillation adsorption for 5min to 1440min to complete the treatment of the heavy metal cadmium wastewater.
After the oscillating adsorption is completed, 10mL of the treated solution is filtered through a 0.45-micrometer water-based filter membrane, the content of heavy metal in each filtrate is measured by using an inductively coupled plasma emission spectrometer (ICP-OES), and the adsorption capacity of the iron-magnesium hydrotalcite @ bentonite composite material to the heavy metal under different time conditions is calculated, and the result is shown in FIG. 10.
FIG. 10 is a graph showing the adsorption effect of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in wastewater under different time conditions in example 9 of the present invention. As can be seen from fig. 10, as time increases, the adsorption of Pb and Cd by the iron-magnesium hydrotalcite and bentonite composite material increases rapidly, Pb reaches adsorption equilibrium within 8 hours, and Cd reaches adsorption equilibrium within 16 hours.
Example 10
An application of an iron-magnesium hydrotalcite @ bentonite composite material in treatment of heavy metal wastewater, specifically, the iron-magnesium hydrotalcite @ bentonite composite material prepared in example 1 is used for respectively treating heavy metal lead wastewater and heavy metal cadmium wastewater, and the method comprises the following steps:
heavy metal lead (Pb) wastewater: 6 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1, 5mg of the iron-magnesium hydrotalcite @ bentonite composite material is added into heavy metal lead wastewater (the volume is 20mL, the pH value is 5) with the concentration of 100mg/L, 150mg/L, 200mg/L, 250mg/L, 300mg/L and 350mg/L respectively, and the heavy metal lead wastewater is placed in a constant temperature water bath kettle at 25 ℃ and 150rpm for shaking adsorption 1440min to complete the treatment of the heavy metal lead wastewater.
Heavy metal cadmium (Cd) wastewater: 6 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1, 5mg of the iron-magnesium hydrotalcite @ bentonite composite material is added into heavy metal cadmium wastewater (the volume is 20mL, the pH value is 5) with the concentration of 50mg/L, 75mg/L, 100mg/L, 125mg/L, 150mg/L and 175mg/L respectively, and the heavy metal cadmium wastewater is placed in a constant temperature water bath kettle at 25 ℃ and 150rpm for shaking adsorption 1440min to complete the treatment of the heavy metal cadmium wastewater.
After the oscillating adsorption is completed, 10mL of the treated solution is filtered through a 0.45-micrometer water system filter membrane, the content of heavy metal in each filtrate is measured by using an inductively coupled plasma emission spectrometer (ICP-OES), and the adsorption capacity of the iron-magnesium hydrotalcite @ bentonite composite material to heavy metal wastewater with different concentrations is calculated, and the results are shown in fig. 11 and fig. 12.
FIG. 11 is a graph showing the adsorption effect of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metal lead in wastewater with different concentrations in example 10 of the present invention. FIG. 12 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metal cadmium in wastewater with different concentrations in example 10 of the present invention. As can be seen from fig. 11 and 12, the initial concentration has a great influence on the adsorption of Pb and Cd by the composite material. The adsorption amounts of Pb and Cd increase with an increase in the initial concentration, and then tend to fluctuate smoothly up and down. This is because the high concentration of Pb and Cd can provide a greater driving force for adsorption for mass transfer of Pb and Cd on the surface of the composite material.
Example 11
The method for investigating the influence of coexisting ions on the adsorption performance of the iron-magnesium hydrotalcite @ bentonite composite material comprises the following steps of:
heavy metal lead (Pb) wastewater: 5 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1 are taken, 5mg of each part is respectively added into heavy metal lead wastewater (the volume is 20mL, the concentration is 300mg/L, and the pH value is 5) containing 0.01M sodium nitrate, 0.01M sodium chloride, 0.01M potassium chloride, 0.01M magnesium chloride and 0.01M calcium chloride, and the wastewater is placed into a constant temperature water bath kettle at the temperature of 25 ℃ and the speed of 150rpm for vibration adsorption 1440min, so that the treatment of the heavy metal lead wastewater is completed.
Heavy metal cadmium (Cd) wastewater: 5 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1 are taken, 5mg of each part is respectively added into heavy metal cadmium wastewater (the volume is 20mL, the concentration is 150mg/L, and the pH value is 5) containing 0.01M sodium nitrate, 0.01M sodium chloride, 0.01M potassium chloride, 0.01M magnesium chloride and 0.01M calcium chloride, and the wastewater is placed in a constant temperature water bath kettle at the temperature of 25 ℃ and the rpm of 150 to be subjected to vibration adsorption for 1440min, so that the treatment of the heavy metal cadmium wastewater is completed.
After the oscillating adsorption is completed, 10mL of the treated solution is filtered through a 0.45-micrometer water-based filter membrane, the content of heavy metal in each filtrate is measured by using an inductively coupled plasma emission spectrometer (ICP-OES), and the adsorption amount of the iron-magnesium hydrotalcite @ bentonite composite material to the heavy metal in the wastewater under different coexisting ion conditions is calculated, and the result is shown in FIG. 13.
FIG. 13 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in wastewater under different coexisting ion conditions in example 11 of the present invention. As can be seen from fig. 13, the presence of multiple coexisting cations (including monovalent and divalent) has very little effect on the adsorption of Pb and Cd by the ferrimagnesium hydrotalcite @ bentonite composite material, and thus the ferrimagnesium hydrotalcite @ bentonite composite material of the present invention can be applied to actual sewage treatment.
Example 12
The method for inspecting the adsorption capacity of the iron-magnesium hydrotalcite @ bentonite composite material in the actual water body comprises the following steps:
heavy metal lead (Pb) wastewater: 3 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1, 5mg of each part of the iron-magnesium hydrotalcite @ bentonite composite material is added into 20mL of heavy metal lead wastewater (prepared by replacing deionized water with tap water, Hunan river water and lake water respectively, and the pH values are all 5) with the concentration of 300mg/L, and the heavy metal lead wastewater is placed in a constant temperature water bath kettle with the temperature of 25 ℃ and the rpm of 150 for vibration adsorption 1440min, so that the treatment of the heavy metal lead wastewater is completed.
Heavy metal cadmium (Cd) wastewater: 5 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1, 5mg of the iron-magnesium hydrotalcite @ bentonite composite material is added into 20mL of heavy metal cadmium wastewater (prepared by replacing pure water with tap water, Hunan river water and lake water respectively, and the pH values are all 5) with the concentration of 150mg/L, and the heavy metal cadmium wastewater is placed in a constant temperature water bath kettle at 25 ℃ and 150rpm for vibration adsorption 1440min to complete the treatment of the heavy metal cadmium wastewater.
After the oscillating adsorption is completed, 10mL of the treated solution is filtered through a 0.45-micrometer water system filter membrane, the content of heavy metal in each filtrate is measured by using an inductively coupled plasma emission spectrometer (ICP-OES), and the adsorption capacity of the iron-magnesium hydrotalcite @ bentonite composite material to the heavy metal in different actual water bodies is calculated, and the result is shown in FIG. 14.
FIG. 14 is a graph showing the adsorption effect of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in different practical water bodies in example 12 of the present invention. As can be seen from FIG. 14, various substances existing in the actual wastewater (including monovalent and divalent substances) have very little influence on the adsorption of Pb and Cd by the iron-magnesium hydrotalcite and bentonite composite material, so that the iron-magnesium hydrotalcite and bentonite composite material has a good application prospect in the actual water pollutant treatment.
Example 13
An application of an iron-magnesium hydrotalcite @ bentonite composite material in treatment of heavy metal wastewater, specifically, the iron-magnesium hydrotalcite @ bentonite composite material prepared in example 1 is used for treating mixed wastewater of heavy metal lead and cadmium, and the method comprises the following steps:
5 parts of the iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) prepared in the example 1, 5mg of the iron-magnesium hydrotalcite @ bentonite composite material is added into mixed wastewater of heavy metal lead and cadmium (the concentration of Cd in the mixed wastewater is 150mg/L, the pH value is 5) with the concentration ratio of Pb to Cd being 1:3, 1:2, 1:1, 2:1 and 3:1 respectively, and the mixed wastewater is placed into a constant temperature water bath kettle at the temperature of 25 ℃ and the rpm of 150 for vibration adsorption 1440min to complete the treatment of the heavy metal mixed wastewater.
After the oscillating adsorption is completed, 10mL of the treated solution is filtered through a 0.45-micrometer water-based filter membrane, the content of heavy metal in each filtrate is measured by using an inductively coupled plasma emission spectrometer (ICP-OES), and the adsorption amount of the iron-magnesium hydrotalcite @ bentonite composite material to the heavy metal in the mixed wastewater is calculated, and the result is shown in FIG. 15.
FIG. 15 is a graph showing the adsorption effect of iron-magnesium hydrotalcite @ bentonite composite material (FeMg-LDH @ B-1) on heavy metals of lead and cadmium in mixed wastewater in example 13 of the present invention. As can be seen from fig. 15, the iron-magnesium hydrotalcite @ bentonite composite material has a stronger adsorption capacity for Pb than Cd, and can be more easily separated from water molecules and converted into bare ions mainly because the hydration energy of Pb is lower than Cd.
Therefore, compared with the conventional adsorbent material, the iron-magnesium hydrotalcite @ bentonite composite material has the advantages of low cost, large adsorption capacity, good stability and the like, is a novel green, environment-friendly and economic adsorbent, can be widely used for treating heavy metal wastewater, can realize efficient and thorough removal of heavy metals in the wastewater, and has high use value and good application prospect.
The above examples are merely preferred embodiments of the present invention, and the scope of the present invention is not limited to the above examples. All technical schemes belonging to the idea of the invention belong to the protection scope of the invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention, and such modifications and embellishments should also be considered as within the scope of the invention.

Claims (10)

1. The iron-magnesium hydrotalcite @ bentonite composite material is characterized by comprising bentonite and iron-magnesium hydrotalcite, wherein the iron-magnesium hydrotalcite @ bentonite composite material is loaded on the surface of the bentonite.
2. The iron-magnesium hydrotalcite @ bentonite composite material as set forth in claim 1, wherein the iron-magnesium hydrotalcite @ bentonite composite material has a petal-like structure; the iron-magnesium hydrotalcite is of a sheet structure; the specific surface area of the iron-magnesium hydrotalcite @ bentonite composite material is 154m2/g。
3. A process for the preparation of the iron-magnesium hydrotalcite @ bentonite composite material according to claim 1 or 2, characterized in that it comprises the following steps:
s1, mixing the magnesium salt, the ferric iron salt, the bentonite and water to obtain a mixed solution;
s2, dropwise adding a mixed solution containing at least one of sodium bicarbonate, sodium carbonate and sodium hydroxide into the mixed solution obtained in the step S1 for coprecipitation reaction until the pH value of the solution is 9.5-10;
s3, aging, washing, drying, grinding and sieving a product obtained after the coprecipitation reaction in the step S2 to obtain the iron-magnesium hydrotalcite @ bentonite composite material.
4. The method according to claim 3, wherein in step S1, the ratio of bentonite, magnesium salt, and ferric salt is 1 g-10 g: 0.04 mol.
5. The method according to claim 4, wherein in step S1, the ratio of bentonite, magnesium salt and ferric salt is 1 g: 0.04 mol.
6. The method according to claim 5, wherein in step S1, the magnesium salt is at least one of magnesium nitrate, magnesium sulfate and magnesium chloride; the ferric salt is at least one of ferric nitrate, ferric chloride and ferric sulfate.
7. The method according to any one of claims 3 to 6, wherein in step S2, the concentrations of sodium bicarbonate, sodium carbonate and sodium hydroxide in the mixed solution are all 0.5 mol/L; the end point pH of the precipitation reaction was 10.
8. The application of the iron-magnesium hydrotalcite @ bentonite composite material as defined in claim 1 or 2 or the iron-magnesium hydrotalcite @ bentonite composite material prepared by the preparation method as defined in any one of claims 3 to 7 in treatment of heavy metal wastewater.
9. Use according to claim 8, characterized in that it comprises the following steps: mixing the iron-magnesium hydrotalcite @ bentonite composite material with heavy metal wastewater to carry out oscillation adsorption, thereby finishing the treatment of the heavy metal wastewater; the iron-magnesium hydrotalcite and bentonite composite material is added in an amount of 0.25g per liter of heavy metal wastewater.
10. The application of claim 9, wherein the heavy metal in the heavy metal wastewater is at least one of Pb and Cd; the concentration of Pb in the heavy metal wastewater is less than or equal to 350 mg/L; the concentration of Cd in the heavy metal wastewater is less than or equal to 175 mg/L; the pH value of the heavy metal wastewater is 3-7; the rotation speed of the oscillation adsorption is 150-200 rpm; the temperature of the oscillation adsorption is 25-45 ℃; the time of the oscillation adsorption is 5min to 1440 min.
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CN115845821A (en) * 2023-02-14 2023-03-28 北京化工大学 Construction method and application of metal organic framework @ layered double hydroxide three-dimensional hierarchical structure adsorbent
CN116099489A (en) * 2022-11-30 2023-05-12 中国科学院东北地理与农业生态研究所 Preparation method of iron-magnesium layered double hydroxide dephosphorizing agent

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CN108704610A (en) * 2018-06-08 2018-10-26 湖南大学 The Mg-Fe ball composite material and preparation method of magnetic carbon modification and application
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CN114774134A (en) * 2022-05-31 2022-07-22 中南大学 Heavy metal contaminated soil remediation agent and preparation method and application thereof
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