阅读说明：本技术 一种有机改性蒙脱石复合材料及其应用 (Organic modified montmorillonite composite material and application thereof ) 是由 徐文坡 卜红玲 刘承帅 陈曼佳 童辉 龙胜桥 于 2021-09-07 设计创作，主要内容包括：本发明公开了一种有机改性蒙脱石复合材料及其应用。这种有机改性蒙脱石复合材料包括蒙脱石和12-氨基十二酸；12-氨基十二酸分散于蒙脱石的层间；有机改性蒙脱石复合材料中有机质的质量百分数≥15％；有机改性蒙脱石复合材料的比表面积≥40.0m～(2)/g。本发明的有机改性蒙脱石复合材料,保留了天然蒙脱石的阳离子交换性,同时具有较高的有机碳含量和内部层间距；制备该有机改性蒙脱石复合材料所需原料储量丰富、价格低廉,且在使用过程中不会对环境造成污染；该有机改性蒙脱石复合材料作为吸附剂对重金属的吸附效率高。(The invention discloses an organic modified montmorillonite composite material and application thereof. The organic modified montmorillonite composite material comprises montmorillonite and 12-amino dodecanoic acid; the 12-amino dodecanoic acid is dispersed among layers of montmorillonite; the mass percentage of organic matters in the organic modified montmorillonite composite material is more than or equal to 15 percent; the specific surface area of the organic modified montmorillonite composite material is more than or equal to 40.0m 2 (ii) in terms of/g. The organic modified montmorillonite composite material of the invention keeps the cation exchange property of natural montmorillonite, and has higher organic carbon content and internal interlayer spacing; the organic modified montmorillonite composite material has rich raw material reserves and low price, and does not cause pollution to the environment in the using process; the organic modified montmorillonite composite material has high adsorption efficiency on heavy metals as an adsorbent.)

1. An organic modified montmorillonite composite material, characterized in that the organic modified montmorillonite composite material comprises montmorillonite and 12-aminododecanoic acid; the 12-amino dodecanoic acid is dispersed among layers of montmorillonite; the mass percentage of organic matters in the organic modified montmorillonite composite material is more than or equal to 15 percent; the specific surface area of the organic modified montmorillonite composite material is more than or equal to 40.0m²/g。

2. A method of preparing the organically modified montmorillonite composite of claim 1, comprising the steps of:

and mixing the 12-aminododecanoic acid solution with montmorillonite for reaction to obtain the organic modified montmorillonite composite material.

3. The method for preparing the organically modified montmorillonite composite material as claimed in claim 2, wherein the purity of montmorillonite is not less than 70%.

4. The method of claim 2, wherein the montmorillonite is a sodium montmorillonite.

5. The method for preparing the organically modified montmorillonite composite material according to claim 2, wherein the mass ratio of the 12-aminododecanoic acid to the montmorillonite is (0.2-0.8): 1.

6. the method of claim 2, wherein the 12-aminododecanoic acid solution is protonated 12-aminododecanoic acid solution.

7. The method of claim 2, wherein the reaction time is 20-40 min.

8. The method of claim 2 wherein the reaction is carried out at a temperature of from 70 ℃ to 90 ℃.

9. A heavy metal adsorbent comprising the organically modified montmorillonite composite of claim 1.

10. Use of the organically modified montmorillonite composite of claim 1 and/or the heavy metal adsorbent of claim 9 for adsorbing heavy metals.

Technical Field

The invention relates to the field of mineral materials, in particular to an organic modified montmorillonite composite material and application thereof.

Background

Montmorillonite is a layered silicate clay mineral, has the characteristics of rich micropores, higher cation exchange capacity, good expansion characteristic, larger surface area and the like, and has good adsorption capacity on heavy metals. Montmorillonite is abundant in reserves, low in cost and environment-friendly, and is widely applied to heavy metal pollution treatment. However, natural montmorillonite has weak binding force of cations to montmorillonite layers, and active sites of the natural montmorillonite can be exchanged by other cations (including inorganic cations and organic cations), so that the adsorption effect is reduced.

To overcome this weakness, organic modification of montmorillonite is one of the important means. In recent years, in studies on an organically modified montmorillonite material, a surfactant has been mainly selected for modifying montmorillonite. However, many of these surfactants are not environmentally friendly. CN109133249A discloses a method for efficiently removing cadmium in seawater by using modified montmorillonite, wherein the prepared composite material can remove heavy metal cadmium in seawater, but toxic and harmful organic reagents such as ammonium pyrrolidine dithiocarbamate and sodium diethylaminodithiocarbamate are required in the preparation process of the material. Therefore, the development of a novel, green and pollution-free modified material to realize high-efficiency adsorption of heavy metal ions is urgently needed.

Disclosure of Invention

In order to overcome the problems of low adsorption efficiency of montmorillonite on heavy metals and secondary pollution in the preparation process of modified montmorillonite in the prior art, the invention aims to provide an organic modified montmorillonite composite material, the invention aims to provide a preparation method of the organic modified montmorillonite composite material, and the invention aims to provide application of the organic modified montmorillonite composite material in adsorption of heavy metals.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

an organic modified montmorillonite composite material comprises montmorillonite and 12-aminododecanoic acid; the 12-amino dodecanoic acid is dispersed among layers of montmorillonite; the mass percentage of organic matters in the organic modified montmorillonite composite material is more than or equal to 15 percent; organic compoundsThe specific surface area of the modified montmorillonite composite material is more than or equal to 40.0m²/g。

Preferably, in the organic modified montmorillonite composite material, the mass percent of organic matters is 15-30%; further preferably, the mass percent of the organic matters is 15-25%; still further preferably, the mass percent of the organic matter is 18-22%.

Preferably, in the organic modified montmorillonite composite material, the specific surface area of the organic modified montmorillonite composite material is 40.0m²/g-80m²(ii)/g; more preferably, the organic modified montmorillonite composite material has a specific surface area of 46.0m²/g-70m²(ii)/g; the specific surface area is measured by the BET method.

The invention also provides a preparation method of the organic modified montmorillonite composite material, which comprises the following steps:

and mixing the 12-aminododecanoic acid solution with montmorillonite for reaction to obtain the organic modified montmorillonite composite material.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the purity of montmorillonite is more than or equal to 70 percent; further preferably, the purity of the montmorillonite is more than or equal to 80 percent.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the montmorillonite is sodium-based montmorillonite; further preferably, the sodium montmorillonite is obtained by modifying original calcium montmorillonite.

Further preferably, when the sodium-based montmorillonite is obtained by modifying original calcium-based montmorillonite, sodium treatment is carried out on the original calcium-based montmorillonite by using a sodium chloride solution; still more preferably, when the sodium treatment is performed on the raw calcium-based montmorillonite by using a sodium chloride solution, the mass ratio of the sodium chloride to the raw calcium-based montmorillonite is (0.4-0.8): 1; still further preferably, sodium treatment is carried out on the original calcium-based montmorillonite by adopting 0.4mol/L-0.8mol/L sodium chloride solution; still more preferably, the raw calcium-based montmorillonite is subjected to sodium treatment with 0.5mol/L sodium chloride solution.

Further preferably, when the sodium montmorillonite is obtained by modifying the original calcium montmorillonite, the reaction temperature in the sodium treatment process is 70-90 ℃; still further preferably, the reaction temperature in the sodium treatment process is 75-85 ℃; still more preferably, the reaction temperature during the sodium treatment is 80 ℃.

Further preferably, when the sodium-based montmorillonite is obtained by modifying original calcium-based montmorillonite, the sodium treatment process of the original calcium-based montmorillonite is carried out for 2 to 4 times; still further preferably, the sodium treatment process of the original calcium-based montmorillonite is carried out for 3 times in total; more preferably, the time of each sodium treatment process is 12-36 h; in some preferred embodiments of the present invention, each sodium treatment time is 24 hours, the sodium treatment is performed in a magnetic stirrer, after the first sodium ion exchange reaction, centrifugation is performed, a fresh sodium chloride solution is added, the exchange is repeated twice, the sodium-based montmorillonite obtained by the sodium treatment is washed by deionized water until no chloride ions exist, and a silver nitrate solution is used for detecting the chloride ion concentration in the deionized water washing solid residue; and (4) freeze-drying the sodium-based montmorillonite subjected to sodium treatment and storing.

Further preferably, when the sodium-based montmorillonite is obtained by modifying original calcium-based montmorillonite, the purity of the original calcium-based montmorillonite is more than or equal to 70 percent; still further preferably, when the sodium-based montmorillonite is obtained by modifying original calcium-based montmorillonite, the purity of the original calcium-based montmorillonite is more than or equal to 80 percent; when the purity does not reach 80%, purifying; the purification method of the original calcium-based montmorillonite is a Stokes natural sedimentation method, and the original calcium-based montmorillonite is crushed, sieved, sedimentated and purified to obtain the original calcium-based montmorillonite; the purification method comprises the following steps: taking 150g of original calcium-based montmorillonite, adding water to prepare a montmorillonite mixed solution with the mass concentration of 30g/L, adding sodium hexametaphosphate as a dispersing agent, wherein the mass ratio of the montmorillonite to the sodium hexametaphosphate is 100: 1, performing ultrasonic treatment, stirring, standing for 24 hours, sucking upper liquid by using a siphon, centrifuging and washing to obtain purified original calcium-based montmorillonite; and performing sodium treatment on the purified calcium-based montmorillonite to obtain the sodium-based montmorillonite.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the mass ratio of the 12-aminododecanoic acid to the montmorillonite is (0.2-0.8): 1; further preferably, the mass ratio of the 12-aminododecanoic acid to the montmorillonite is (0.3-0.6): 1; still further preferably, the mass ratio of 12-aminododecanoic acid to montmorillonite is 0.47: 1.

preferably, in the preparation method of the organic modified montmorillonite composite material, montmorillonite is firstly prepared into montmorillonite solution before being mixed with 12-aminododecanoic acid solution; further preferably, the concentration of the montmorillonite solution is 5g/L-20 g/L; still more preferably, the concentration of the montmorillonite solution is 8g/L-12 g/L; still more preferably, the concentration of the montmorillonite solution is 10 g/L.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the 12-aminododecanoic acid solution is a protonated 12-aminododecanoic acid solution; further preferably, the protonation step is: the 12-aminododecanoic acid solution is mixed with the protonated solution.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the protonation solution used in the protonation treatment of the 12-aminododecanoic acid solution is at least one of a hydrochloric acid solution and a sulfuric acid solution; further preferably, the protonation solution is a hydrochloric acid solution; still more preferably, the molar mass ratio of 12-aminododecanoic acid to hydrochloric acid at the time of protonation reaction is (0.5-1): 1; still more preferably, the concentration of the hydrochloric acid solution is 0.1mol/L to 0.2 mol/L.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the reaction time is 20min-40 min; further preferably, the reaction time is 25min-35 min; still more preferably, the reaction time is 30 min.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the reaction temperature is 70-90 ℃; further preferably, the reaction temperature is 75-85 ℃; still more preferably, the temperature of the reaction is 80 ℃.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the reaction is carried out in a water bath kettle.

Preferably, in the preparation method of the organic modified montmorillonite composite material, the reaction is carried out under the condition of oscillation or stirring.

Preferably, the preparation method of the organic modified montmorillonite composite material further comprises a separation step, wherein the separation mode is centrifugal separation, the 12-aminododecanoic acid solution is mixed with montmorillonite for reaction and then is subjected to centrifugal separation, and the solid component obtained by separation is the organic modified montmorillonite composite material; further preferably, the centrifugal separation rotating speed is 8000rpm-12000rpm, and the centrifugal separation time is 10-20 min; still further preferably, the centrifugal separation rotating speed is 9000rpm-11000rpm, and the centrifugal separation time is 12-18 min; still more preferably, the centrifugal separation rotation speed is 10000rpm, and the centrifugal separation time is 15 min.

Preferably, the preparation method of the organic modified montmorillonite composite material also comprises a washing step, wherein the organic modified montmorillonite composite material obtained after separation needs to be washed by water; further preferably, the washing times are more than or equal to 5; more preferably, the number of washing is 7 or more.

The invention also provides a heavy metal adsorbent which comprises the organic modified montmorillonite composite material.

The invention also provides application of the organic modified montmorillonite composite material and/or the heavy metal adsorbent in heavy metal adsorption.

Preferably, the organic modified montmorillonite composite material and/or the heavy metal adsorbent is applied to adsorbing heavy metals, wherein the heavy metals are at least one of copper, lead, cadmium, arsenic, chromium and mercury; more preferably, the heavy metal is at least one of cadmium, arsenic, chromium and lead; still more preferably, the heavy metal is at least one of cadmium and lead.

Preferably, the organic modified montmorillonite composite material and/or the heavy metal adsorbent are/is applied to adsorbing heavy metals, and the heavy metals are heavy metals in any system of air, soil, water body, sludge and bottom mud; further preferably, the heavy metal is a heavy metal in soil or water.

Preferably, the organic modified montmorillonite composite material and/or the heavy metal adsorbent is applied to adsorbing heavy metals, and when the heavy metals are heavy metals in any system of soil, water, sludge and sediment, the pH range of the organic modified montmorillonite composite material for adsorbing the heavy metals is 3-11; further preferably, when the heavy metal is in any system of soil, water, sludge and sediment, the pH range of the organic modified montmorillonite composite material for adsorbing the heavy metal is 7-11; still more preferably, when the heavy metal is heavy metal in any system of soil, water, sludge and sediment, the pH range of the organic modified montmorillonite composite material for adsorbing the heavy metal is 9-11.

The invention also provides a method for adsorbing heavy metal by the organic modified montmorillonite composite material, which comprises the following steps:

1) mixing the organic modified montmorillonite composite material with heavy metal wastewater, and reacting to obtain a mixed solution;

2) separating the mixed liquor in the step 1) to remove solids, thereby realizing the removal of heavy metals in the wastewater.

Preferably, in the method for adsorbing heavy metal by using the organic modified montmorillonite composite material, in the step 1), the heavy metal is at least one of copper, lead, cadmium, arsenic, chromium and mercury; more preferably, the heavy metal is at least one of cadmium, arsenic, chromium and lead; still more preferably, the heavy metal is at least one of cadmium and lead.

Preferably, in the method for adsorbing heavy metal by using the organic modified montmorillonite composite material, the mass ratio of the montmorillonite composite material to the heavy metal in the step 1) is 1: (0.001-0.1); further preferably, the mass ratio of the montmorillonite composite material to the heavy metal in the step 1) is 1: (0.01-0.1); still further preferably, the mass ratio of the montmorillonite composite material to the heavy metal in the step 1) is 1: (0.05-0.1).

Preferably, in the method for adsorbing heavy metal by using the organic modified montmorillonite composite material, the concentration of the heavy metal in the heavy metal wastewater in the step 1) is 10mg/L-200 mg/L; further preferably, the concentration of the heavy metal in the heavy metal wastewater in the step 1) is 30mg/L-150 mg/L; still more preferably, the concentration of heavy metal in the heavy metal in step 1) is 60mg/L to 80 mg/L.

Preferably, in the method for adsorbing heavy metal by using the organic modified montmorillonite composite material, the reaction time in the step 1) is 12-48 h; further preferably, the reaction time in step 1) is 20h to 28 h.

Preferably, the method for adsorbing heavy metal by the organic modified montmorillonite composite material is that the reaction in the step 1) is carried out under the condition of oscillation or stirring; further preferably, the reaction in step 1) is carried out under shaking conditions.

Preferably, the method for adsorbing heavy metal by the organic modified montmorillonite composite material has the advantages that the pH value of the reaction in the step 1) is 3-11; further preferably, the pH of the reaction in step 1) is 7 to 11; still further preferably, the pH of the reaction in step 1) is from 9 to 11.

Preferably, in the method for adsorbing heavy metal by using the organic modified montmorillonite composite material, the separation mode in the step 2) is one of centrifugation and filtration; further preferably, the separation in step 2) is performed by filtration.

The invention has the beneficial effects that:

(1) the organic modified montmorillonite composite material of the invention keeps the cation exchange property of natural montmorillonite, and has higher organic carbon content and internal interlayer spacing.

(2) 12-aminododecanoic acid is an alkyl long carbon chain organic matter containing carboxyl and amino groups, and has no harmful organic group; and the organic matter can be intercalated into the interlayer of the montmorillonite by a cation exchange method, so that the interlayer spacing and the surface active group of the montmorillonite are obviously increased. According to the invention, 12-aminododecanoic acid is used for modifying montmorillonite, so that organic matters enter the interlayer of the montmorillonite, the interlayer spacing and surface active groups of the montmorillonite are increased, and the adsorption effect on heavy metals is improved. Meanwhile, the organic matter is non-toxic and harmless, does not cause environmental pollution in the preparation and application processes, and can avoid secondary pollution to the environment while improving the heavy metal adsorption effect.

(3) The preparation process of the organic modified montmorillonite composite material is simple and easy to implement, has low equipment requirement and is easy to realize large-scale batch production.

(4) The organic modified montmorillonite composite material has rich raw material reserves and low price, does not pollute the environment in the preparation and use processes, and can obtain larger economic benefit with lower investment.

(5) The organic modified montmorillonite composite material disclosed by the invention has high adsorption efficiency on heavy metals, can be used as an adsorbent to quickly and efficiently adsorb and remove heavy metals in systems such as water, soil, sludge, bottom mud and the like, and has a good application prospect in the adsorption and removal of the heavy metals in an alkaline soil environment.

Drawings

FIG. 1 is an XRD pattern of an organically modified montmorillonite composite prepared in example 1;

FIG. 2 is an infrared spectrum of the organically modified montmorillonite composite prepared in example 1;

FIG. 3 is a schematic diagram showing the adsorption amount of cadmium in an acidic solution of the organically modified montmorillonite composite prepared in example 1 and a montmorillonite raw material;

FIG. 4 is a graph showing the adsorption amount of cadmium in a neutral solution of the organically modified montmorillonite composite prepared in example 1 and a montmorillonite raw material;

FIG. 5 is a diagram showing the adsorption amount of cadmium in an alkaline solution for the organically modified montmorillonite composite prepared in example 1 and a montmorillonite raw material;

fig. 6 is an X-ray photoelectron spectrum of cadmium adsorbed by the organically modified montmorillonite composite material prepared in example 1 at pH 9;

fig. 7 is a schematic diagram showing the lead adsorption amount of the organically modified montmorillonite composite material and the montmorillonite raw material prepared in example 1 in an alkaline solution.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The starting materials, reagents or equipment used in the examples are, unless otherwise specified, either conventionally commercially available or may be obtained by methods known in the art. Unless otherwise indicated, the testing or testing methods are conventional in the art.

Example 1

The procedure for the preparation of the organically modified montmorillonite composite is as follows:

(1) taking a montmorillonite raw material which is calcium-based montmorillonite, crushing, sieving with a 200-mesh sieve, and settling and purifying to obtain montmorillonite powder.

(2) Taking 10g of the montmorillonite powder obtained in the step (1), adding the montmorillonite powder into 200mL of sodium chloride solution with the concentration of 0.5mol/L, and stirring on a magnetic stirrer at the rotation speed of 550rpm and the constant temperature of 80 ℃; after 24h, the montmorillonite is separated from the solution, fresh sodium chloride solution is added again, and the exchange is repeated twice; and (3) centrifuging the solution after cation exchange, washing the solid residue with deionized water, detecting with a silver nitrate solution until no chloride ion exists, obtaining the sodium-based montmorillonite, and storing after freeze drying.

(3) 4.75g of 12-aminododecanoic acid was added to 200ml of a beaker containing 0.14mol/L hydrochloric acid solution, and after heating treatment at 80 ℃, it was dissolved and protonated.

(4) And (3) adding 10g of the sodium montmorillonite obtained in the step (2) into distilled water to prepare a sodium montmorillonite suspension with the mass concentration of 1.0%.

(5) And (4) mixing the protonated organic solution in the step (3) and the sodium-based montmorillonite suspension in the step (4), placing the mixture in a water bath kettle, keeping the temperature at 80 ℃, and stirring the mixture for 30min by magnetic stirring.

(6) The suspension after the reaction in step (5) was centrifuged at 10000rpm for 15min, and the supernatant was discarded. And the solid was washed seven more times with hot water until the wash pH was 5.0. And finally, freeze-drying the solid sample to obtain the organic modified montmorillonite composite material, grinding the composite material to be below 200 meshes by an agate mortar, and sealing and storing the composite material.

The XRD pattern of the organically modified montmorillonite composite material prepared in this example is shown in FIG. 1. Compared with the interlayer spacing of 1.21nm of sodium-based montmorillonite, the interlayer spacing of the organic modified montmorillonite is 1.63nm, and the interlayer spacing is increased by 0.42nm, which indicates that organic matters enter the interlayer of the montmorillonite. The infrared spectrum of the organically modified montmorillonite composite prepared in this example is shown in FIG. 2. As can be seen from fig. 2, the organic modified montmorillonite has organic matters and characteristic peaks of montmorillonite, and new peaks appear in the organic modified montmorillonite, further indicating that the organic matters enter into the interlayer of montmorillonite.

The organic modified montmorillonite is tested by methods such as X-ray diffraction analysis, chemical analysis, infrared spectrum analysis and the like, and the result shows that the prepared organic modified montmorillonite isThe modified montmorillonite phase composition is sodium montmorillonite of 12-amino dodecanoic acid intercalation, and the organic matter content is 20%. The BET specific surface area of the adsorbent measured by nitrogen adsorption-desorption method was 46.0m²The specific surface area of ethylene glycol ethyl ether (EGME) measured by the adsorption method is 551.1m²/g。

Example 2

The steps of adsorbing the cationic heavy metal cadmium by the organic modified montmorillonite composite material are as follows:

(1) cadmium nitrate (Cd (NO)₃)₂) Is Cd²⁺Source, prepare 50.0mL Cd²⁺Solutions with concentrations of 1mg/L, 5mg/L, 10mg/L, 25mg/L, 50mg/L, 75mg/L, 100mg/L were prepared, and pH values of the solutions were adjusted to 3.0 and 5.0.

(2) Weighing 50mg of the organic modified montmorillonite composite material prepared in the example 1, adding the organic modified montmorillonite composite material into the prepared solution, fully oscillating and reacting for 24 hours, then carrying out centrifugal separation, filtering supernatant liquid by using a 0.22 micron water system filter head, storing filtrate, and testing the concentration of Cd by using an inductively coupled plasma emission spectrometer; when the pH value is 3.0, the saturated adsorption capacity of the organic modified montmorillonite composite material to Cd is 13.99mg/g, and when the pH value is 5.0, the saturated adsorption capacity of the organic modified montmorillonite composite material to Cd is 19.92 mg/g.

A schematic diagram of the adsorption capacity of the organic modified montmorillonite composite material to cadmium is shown in figure 3, wherein OM-Mt represents the organic modified montmorillonite.

The adsorption experiment was carried out by using the raw material of montmorillonite which had not been subjected to any treatment in example 1 as a comparative example, and replacing the above-mentioned organic modified montmorillonite composite with untreated montmorillonite, and the other experimental conditions were all in agreement. The saturated adsorption capacity of the montmorillonite raw material to Cd is measured to be 31.43mg/g under the condition that the pH value is 3.0, and the saturated adsorption capacity of the montmorillonite raw material to Cd is measured to be 35.44mg/g under the condition that the pH value is 5.0.

A schematic diagram of the adsorption of cadmium by the montmorillonite raw material is shown in FIG. 3, wherein Mt represents the montmorillonite raw material.

Example 3

The steps of adsorbing the cationic heavy metal cadmium by the organic modified montmorillonite composite material are as follows:

(1) cadmium nitrate (Cd (NO)₃)₂) Is Cd²⁺Source, prepare 50.0mL Cd²⁺The solution was adjusted to a pH of 7.0 at concentrations of 1mg/L, 5mg/L, 10mg/L, 25mg/L, 50mg/L, 75mg/L, and 100 mg/L.

(2) Weighing 50mg of the organic modified montmorillonite composite material prepared in the embodiment 1, adding the organic modified montmorillonite composite material into the prepared solution, fully oscillating and reacting for 24 hours, then carrying out centrifugal separation, filtering supernatant liquid by using a 0.22 micron water system filter head, storing filtrate and testing the concentration of Cd by using an inductively coupled plasma emission spectrometer; when the pH value is 7.0, the saturated adsorption capacity of the organic modified montmorillonite composite material to Cd is 21.17 mg/g.

A schematic diagram of the adsorption capacity of the organic modified montmorillonite composite material to cadmium is shown in figure 4, wherein OM-Mt represents the organic modified montmorillonite.

The adsorption experiment was carried out by using the raw material of montmorillonite which had not been subjected to any treatment in example 1 as a comparative example, and replacing the above-mentioned organic modified montmorillonite composite with untreated montmorillonite, and the other experimental conditions were all in agreement. When the pH value is 7.0, the saturated adsorption capacity of the montmorillonite raw material to Cd is 38.71 mg/g.

A schematic diagram of the adsorption of cadmium by the montmorillonite raw material is shown in FIG. 4, wherein Mt represents the montmorillonite raw material.

Example 4

The steps of adsorbing the cationic heavy metal cadmium by the organic modified montmorillonite composite material are as follows:

(1) cadmium nitrate (Cd (NO)₃)₂) Is Cd²⁺Source, prepare 50.0mL Cd²⁺Solutions with concentrations of 1mg/L, 5mg/L, 10mg/L, 25mg/L, 50mg/L, 75mg/L, 100mg/L were prepared, and pH values of the solutions were adjusted to 9.0 and 11.

(2) Weighing 50mg of the organic modified montmorillonite composite material prepared in the example 1, adding the organic modified montmorillonite composite material into the prepared solution, fully oscillating and reacting for 24 hours, then carrying out centrifugal separation, filtering supernatant liquid by using a 0.22 micron water system filter head, storing filtrate, and testing the concentration of Cd by using an inductively coupled plasma emission spectrometer; when the pH value is 9.0, the saturated adsorption capacity of the organic modified montmorillonite composite material to Cd is 50.21mg/g, and when the pH value is 11.0, the saturated adsorption capacity of the organic modified montmorillonite composite material to Cd is 70.02 mg/g.

A schematic diagram of the adsorption amount of cadmium by the organic modified montmorillonite composite material is shown in figure 5, wherein OM-Mt represents the organic modified montmorillonite.

The X-ray photoelectron spectrum of the organic modified montmorillonite composite material adsorbing cadmium under the condition of pH 9 in the example is shown in the attached figure 6. As can be seen from the figure, cadmium element has three peaks, wherein the characteristic peak with the binding energy of 406.34 eV can be attributed to the formation of CdO or Cd (OH)₂(ii) a The characteristic peak of the binding energy is 402.60eV, which is attributed to the formation of a nitrogen-containing compound by the combination of cadmium element and an amide group.

The adsorption experiment was carried out by using the raw material of montmorillonite which had not been subjected to any treatment in example 1 as a comparative example, and replacing the above-mentioned organic modified montmorillonite composite with untreated montmorillonite, and the other experimental conditions were all in agreement. When the pH value is 9.0, the saturated adsorption capacity of the montmorillonite raw material to Cd is 43.20mg/g, and when the pH value is 11.0, the saturated adsorption capacity of the montmorillonite raw material to Cd is 47.70 mg/g.

A schematic diagram of the adsorption of cadmium by the montmorillonite raw material is shown in FIG. 5, wherein Mt represents the montmorillonite raw material.

Example 5

The steps of adsorbing the cationic heavy metal lead by the organic modified montmorillonite composite material are as follows:

(1) with lead nitrate (Pb (NO)₃)₂) Is Pb²⁺Source, prepare 50.0mL of Pb²⁺The solution was adjusted to a pH of 9.0 at concentrations of 1mg/L, 5mg/L, 10mg/L, 25mg/L, 50mg/L, 75mg/L, and 100 mg/L.

(2) Weighing 50mg of the organic modified montmorillonite composite material prepared in the example 1, adding the organic modified montmorillonite composite material into the prepared solution, fully oscillating and reacting for 24 hours, then carrying out centrifugal separation, filtering supernatant liquid by using a 0.22 micron water system filter head, storing filtrate, and testing the Pb concentration by using an inductively coupled plasma emission spectrometer; when the pH was found to be 9.0, the saturated adsorption amount of Pb on the organically modified montmorillonite composite was 73.98 mg/g.

A schematic diagram of the lead adsorption capacity of the organically modified montmorillonite composite material is shown in FIG. 7, wherein OM-Mt represents organically modified montmorillonite. As can be seen from FIG. 7, the adsorption effect of the organically modified montmorillonite on Pb was optimized at an initial Pb concentration of 75 mg/L.

The adsorption experiment was carried out by using the raw material of montmorillonite which had not been subjected to any treatment in example 1 as a comparative example, and replacing the above-mentioned organic modified montmorillonite composite with untreated montmorillonite, and the other experimental conditions were all in agreement. When the pH was found to be 9.0, the saturated adsorption amount of the montmorillonite material for Pb was found to be 69.79 mg/g.

A schematic diagram of the amount of lead adsorbed by the smectite starting material is shown in FIG. 7, where Mt represents the smectite starting material.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.