Preparation method of a specific adsorption material for solving heavy metal endogenous pollution in water body

Abstract

The application discloses a preparation method of a specific adsorption material for solving heavy metal endogenous pollution in water bodies. The specific ecological adsorption material is mainly made of ecological materials such as chitosan, natural clinoptilolite and specific adsorption material for specific pollutants in specific areas, and has the function of treating various endogenous pollutants in river channels. The specific ecological adsorption material uses natural clinoptilolite to enhance the mechanical strength of the chitosan hydrogel material, so that it can still maintain a stable cross-linked network structure under the action of a certain hydraulic intensity and external force, and provides a loading site for the specific adsorption material for specific pollution. The chitosan and natural clinoptilolite in the specific ecological adsorption material have strong fixing capacity for heavy metal pollution, and in addition, the natural clinoptilolite also has strong adsorption performance for organic pollutants such as ammonia and nitrogen; and the loading of the specific adsorption material can realize targeted removal of certain pollutants in the environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic adsorption material synthesis and river in-situ pollution remediation, and particularly relates to a preparation method of a specific adsorption material for solving water heavy metal in-situ pollution. BACKGROUND

[0002] Long-term industrial and agricultural development has led to a large amount of heavy metals and nitrogen and phosphorus organic matter accumulated in river sediments, gradually forming in-situ pollution hazards, which will cause the re-release of heavy metals and ammonia nitrogen organic matter from the sediments to cause secondary pollution of the water phase when the external environmental conditions such as pH, Eh and Do change. At present, river pollution treatment mainly includes in-situ treatment and ex-situ treatment, but ex-situ treatment often needs to treat the dredged sediments, which not only destroys the river ecology, but also faces many problems such as transportation, storage, subsequent treatment and discharge of the dredged sediments, and generally has high cost, which is not suitable for wide promotion and application.

[0003] At present, most of the in-situ treatment technologies for heavy metal in sediments have certain limitations. For example, the patent document CN111646659A discloses a heavy metal contaminated sediment solidifying agent and a solidifying method thereof, the solidifying agent contains ammonium persulfate, polyaluminum chloride, polyacrylamide, pentanediol and a large amount of chemical reagents, which brings new pollution hazards while remedying the pollution. For another example, the patent document CN113548778A discloses a biological remediation method for heavy metal-organic compound contaminated river sediments, which solidifies the sediment pollutants by directional domestication of acidophilic electroactive bacteria, but this kind of microbial remediation method does not consider whether the actual river ecology is suitable for introducing the bacterial population to breed, and the possible influence of introducing the bacterial population on the river ecology, and does not have universality. The defects of the current mainstream in-situ treatment technologies mainly include the following three points: (1) poor migration and generalizability; (2) the selected materials are not environmentally friendly; (3) the monitoring mechanism is generally absent in the remediation process, and the solidification effect in the actual treatment is not discussed. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a method for preparing a specific ecological adsorption material with high efficiency, low cost and environmental friendliness to solve the problems in the background art.

[0005] The application provides the following technical solutions:

[0006] A preparation method of a specific adsorption material for solving water heavy metal in-situ pollution, comprising the following steps:

[0007] S1, grinding natural clinoptilolite into powder and passing it through a 200-mesh sieve for standby;

[0008] S2, a certain amount of sieved zeolite is weighed, sodium hydroxide solution is added, and constant stirring is carried out under the action of a constant temperature water bath to obtain alkali-modified zeolite, which is washed with deionized water and dried for standby use;

[0009] S3, the alkali-modified zeolite and chitosan are added to the ice acetic acid solution in a certain proportion, and stirring is carried out for 1 h to make the chitosan fully dissolved;

[0010] S4, a certain amount of specific adsorption material is added to the system in step S3, and stirring is carried out for 1 h to make it fully mixed;

[0011] S5, a certain amount of epichlorohydrin is added to the system in step S4, and stirring is carried out for 2 h to make it fully mixed;

[0012] S6, the solution in the system in step S5 is added dropwise to a certain concentration of sodium tripolyphosphate solution at a constant speed using a peristaltic pump, and stirring is carried out for 3 h to make it fully mixed;

[0013] S7, the system in step S6 is titrated with standard sodium hydroxide solution and hydrochloric acid solution until the pH is 5, and after standing for a period of time, the hydrogel beads are taken out and washed and dried to obtain specific ecological adsorption material.

[0014] Further, in step S2, the amount of zeolite added is 20 g.

[0015] Further, in step S2, the concentration of the sodium hydroxide solution is 2 mol / l, the constant temperature water bath temperature is 75-85℃, and the stirring time is 7.5-8.5 h. The constant temperature water bath temperature is preferably 80℃, and the stirring time is preferably 8 h.

[0016] Further, in step S3, the amount of chitosan added is 10 g, the ice acetic acid solution is 100 ml, and the volume fraction is 3%-5%. The volume fraction is preferably 5%.

[0017] Further, in step S4, the specific adsorption material is one of expanded vermiculite and corn straw biochar.

[0018] Further, the amount of specific adsorption material added is 10 g.

[0019] Further, the specific preparation method of the expanded vermiculite as a specific adsorption material includes the following steps:

[0020] A1, the vermiculite is preheated in a 150℃ oven for 10 min, then quickly placed in a 1000℃ muffle furnace for 1 min to make it expand, and then quickly taken out;

[0021] A2, after cooling, it is put into a ball mill for grinding and then sieved through a 200 mesh sieve for standby use.

[0022] Further, the specific preparation method of the corn stalk biochar as a specific adsorption material comprises the following steps:

[0023] B1, the corn stalk is washed and dried at 80 DEG C, crushed and passed through a 100 mesh sieve;

[0024] B2, placed in a muffle furnace at 500 DEG C for carbonization for 8 hours;

[0025] B3, treated with 200 mL of 1 mol / l HCl for 12 hours, washed and dried for standby.

[0026] Further, in step S5, the addition amount of the epichlorohydrin is 3 ml.

[0027] Further, in step S6, the concentration of the sodium tripolyphosphate solution is 20 g / l.

[0028] Further, in step S6, the speed of the peristaltic pump is 2.5-3.5 r / min.

[0029] Further, in step S6, the output end of the peristaltic pump is provided with a silica gel tube, and the specification of the silica gel tube is 2*4 mm.

[0030] Further, in step S7, the standing time is 2.5-3.5 hours.

[0031] Further, the application of a specific adsorption material for solving water body heavy metal endogenous pollution in situ treatment of river endogenous pollution is applied to be laid on the contaminated river sediment, and a proper amount of plants are planted to ensure the stability of the benthic environment.

[0032] Further, the plant is a hyperaccumulator selected for the pollution in the area, and emergent or submerged plants are selected according to the specific water depth.

[0033] Further, the plant can fix the pollution migrated to the cover layer, and the root, stem and leaf are collected regularly, and the heavy metal, nitrogen and phosphorus content is determined to analyze the pollution repair situation and predict the endogenous pollution release risk in advance.

[0034] Further, the application of a specific adsorption material for solving water body heavy metal endogenous pollution in situ treatment of river endogenous pollution is applied to be laid on the contaminated river sediment, and a proper amount of plants are planted to ensure the stability of the benthic environment.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] (1) The application is a preparation method of a specific adsorption material for solving heavy metal endogenous pollution in water bodies. The specific adsorption material is made of ecological materials with high biological affinity, such as chitosan, natural clinoptilolite and specific adsorption material for specific pollutants in specific areas. The specific adsorption material has significant remediation effect on heavy metal and organic pollutant.

[0037] (2) The application is a preparation method of a specific adsorption material for solving heavy metal endogenous pollution in water bodies. The specific adsorption material is made of ecological materials with high biological affinity, such as chitosan, natural clinoptilolite and specific adsorption material for specific pollutants in specific areas. The specific adsorption material has significant remediation effect on heavy metal and organic pollutant.

[0038] (3) The application is a preparation method of a specific adsorption material for solving heavy metal endogenous pollution in water bodies. The specific adsorption material is made of ecological materials with high biological affinity, such as chitosan, natural clinoptilolite and specific adsorption material for specific pollutants in specific areas. The specific adsorption material has significant remediation effect on heavy metal and organic pollutant. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0040] Figure 1 The figure is a preparation process of the specific ecological adsorption material of the application.

[0041] Figure 2 The figure is a scanning electron microscope image of the alkali modified zeolite in the preparation process of the application.

[0042] Figure 3 The figure is a physical image of the specific ecological adsorption material of example 1 of the application.

[0043] Figure 4 The figure is a scanning electron microscope image of the specific ecological adsorption material of example 1 of the application.

[0044] Figure 5 The figure is a CEC comparison chart of the specific ecological adsorption material of example 1 of the application and the original material.

[0045] Figure 6 The figure is an adsorption effect comparison chart of the specific ecological adsorption material of example 1 of the application and the original material.

[0046] Figure 7 The physical map of the specific ecological adsorption material for the embodiment 2 of the present application.

[0047] Figure 8 The scanning electron microscope map of the specific ecological adsorption material for the embodiment 1 of the present application.

[0048] Figure 9 The CEC comparison map of the specific ecological adsorption material for the embodiment 2 of the present application and the original material.

[0049] Figure 10 The adsorption effect comparison map of the specific ecological adsorption material for the embodiment 2 of the present application and the original material. DETAILED DESCRIPTION

[0050] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0051] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0052] The present application does not limit the state, dosage, etc. of the specific adsorption material, which can be determined by a person skilled in the art according to actual needs.

[0053] The present application does not specifically limit the application mode and dosage of the specific adsorption material, which can be set by a person skilled in the art according to actual needs.

[0054] The in-situ adsorption material provided by the present application realizes removal and solidification of various pollutants, and has high removal rate.

[0055] The preparation method and application of the specific ecological adsorption material provided by the present application will be described in detail below in combination with embodiments, but they should not be understood as limitations on the protection scope of the present application.

[0056] Embodiment 1

[0057] Please refer to Figures 1-10As shown, for the endogenous pollution of river heavy metal copper, a specific ecological adsorption material is prepared and applied.

[0058] After the zeolite is put into a ball mill for grinding and passing through a 200-mesh sieve, 20 g of zeolite powder is weighed into a 250-ml round-bottom flask, 200 ml of a 2 mol / l sodium hydroxide solution is poured in, and after heating at 80°C in a constant-temperature water bath for 8 h, it is taken out, washed, dried, and placed in another round-bottom flask, 10 g of BR-grade chitosan powder is added, 100 ml of 5% glacial acetic acid solution is poured in, and stirring is performed for 1 h to fully dissolve the chitosan.

[0059] After the vermiculite is preheated in a 150°C oven for 10 min, it is quickly placed in a 1000°C muffle furnace and left to stand for 1 min to expand it, and then it is quickly taken out, cooled, and put into a ball mill for grinding and passing through a 200-mesh sieve, 10 g of expanded vermiculite powder is weighed into a (1) beaker, stirring is performed for 1 h to uniformly mix the suspension, and then 3 ml of epichlorohydrin is added dropwise, and stirring is performed for 2 h to fully react it.

[0060] The speed of the peristaltic pump is set to 3 r / min, the above-mentioned suspension is added dropwise into a 200-ml solution of 20 g / l sodium tripolyphosphate solution in a 2*4 mm silica gel tube, stirring is continuously performed for 3 h, and then standard sodium hydroxide and hydrochloric acid solutions are used for titration until the pH is 5, the hydrogel beads are taken out after standing for 3 h, washed with deionized water, dried in an oven, and the specific ecological adsorption material is obtained as shown in Figure 3 .

[0061] For copper endogenous pollution, considering the adsorption effect, ecological type, and economy, expanded vermiculite is selected as a specific adsorption material. Vermiculite is a layered silicate mineral, and the main components contain aluminum, iron oxides, all of which have specific adsorption effects on copper. After calcination, the interlayer spacing of silicate is reduced, the water vapor is limited, the interlayer water vapor pressure is increased, the volume can be expanded by 6.5 times at most, and it has a larger specific surface area and active point adsorption of Cu. In addition, it is environmentally friendly, cheap and easy to obtain, and is a relatively ideal specific adsorption material for copper.

[0062] As shown in Figure 2 and Figure 4 As shown by comparison, after adding chitosan and expanded vermiculite, the specific ecological adsorption material has more lattice pores per unit area than natural zeolite, the surface roughness increases, the specific surface area significantly increases, the natural structure is improved, and the adsorption capacity is enhanced.

[0063] As shown in Figure 5 As shown by comparison, the CEC value of the specific ecological adsorption material is 2.4 times that of natural zeolite and 1.7 times that of alkali-modified zeolite, and the adsorption capacity of the specific ecological adsorption material is greatly improved compared with the former two.

[0064] Figure 6 The concentration changes of the mud-water phases during the experiment of the release process of the endogenous pollution in the mud under the coverage of natural zeolite, alkali-modified zeolite and specific ecological adsorption material can be seen. In the case that the reduction degree of the copper concentration in the mud is similar, the water phase concentration of the system under the coverage of the specific adsorption material is 13.2% and 18.1% of the natural zeolite and the alkali-modified zeolite respectively when the system reaches stability. In the case that the copper release amount is similar, the specific adsorption material captures more copper, which weakens the risk of endogenous pollution.

[0065] Example 2

[0066] The specific ecological adsorption material is prepared and applied for the endogenous pollution of heavy metal cadmium in the river.

[0067] The zeolite is ground in a ball mill and then sieved through a 200-mesh sieve. 20 g of the zeolite powder is weighed in a 250-ml round-bottom flask, 200 ml of a 2-mol / l sodium hydroxide solution is poured in, and the flask is heated in a 80℃ constant-temperature water bath for 8 h. After being taken out, the zeolite is washed, dried, and then placed in another round-bottom flask. 10 g of BR-grade chitosan powder is added, 100 ml of 5% glacial acetic acid solution is poured in, and the chitosan is stirred for 1 h to make it fully dissolved.

[0068] The corn straw is washed and dried at 80℃, crushed and sieved through a 100-mesh sieve. The corn straw is carbonized in a muffle furnace at 500℃ for 8 h. The carbonized corn straw is treated with 200 mL of 1-mol / l HCl for 12 h, washed and dried. 10 g of the carbonized corn straw powder is weighed and placed in the above-mentioned flask. The suspension is stirred for 1 h to make it uniformly mixed. Then, 3 ml of epichlorohydrin is added dropwise, and the suspension is stirred for 2 h to make it fully react.

[0069] The speed of the peristaltic pump is set to 3 r / min. The above-mentioned suspension is added dropwise into 200 ml of a 20-g / l sodium tripolyphosphate solution in a 2*4 mm silica gel tube. After continuous stirring for 3 h, the pH is titrated to 5 with standard sodium hydroxide and hydrochloric acid solutions. After being left to stand for 3 h, the hydrogel beads are taken out, washed with deionized water, and dried in an oven to obtain the specific ecological adsorption material. Figure 7 .

[0070] For the endogenous pollution of cadmium, the corn straw biochar is selected as the specific adsorption material in consideration of the adsorption effect, ecological type and economy. The surface of the corn straw biochar has a large number of active sites of oxygen-containing functional groups, such as hydroxyl and carboxyl groups, which can exchange ions with cadmium. In addition, the π electrons on the surface of the corn straw biochar can specifically interact with the coordination bond of cadmium to fix cadmium. Moreover, the cost of corn straw is extremely low, and it is easy to obtain and friendly to the environment. Therefore, the corn straw biochar is an ideal specific adsorption material for cadmium.

[0071] As shown in Figure 2 and Figure 8As shown in comparison, Figure 2 and Figure 4 As shown in comparison, after adding chitosan and corn straw biochar, the specific ecological adsorption material has more lattice pores per unit area, the roughness of the surface increases, the specific surface area significantly increases, the natural structure is improved, and the adsorption capacity is enhanced.

[0072] As shown in comparison, Figure 9 As shown in comparison, the CEC value of the specific ecological adsorption material is 2.7 times that of natural zeolite and 1.9 times that of alkali modified zeolite, and the adsorption capacity of the specific ecological adsorption material is greatly improved compared with the former two.

[0073] Figure 10 The simulation is the concentration change of mud-water two phases in the process of releasing endogenous pollution of sediment under the condition of covering natural zeolite, alkali modified zeolite and specific ecological adsorption material, it can be seen that in the case of similar decrease of copper concentration in sediment, the water phase concentration under the condition of covering specific adsorption material is 10.4% and 15.8% of that of natural zeolite and alkali modified zeolite respectively when the system reaches stability, and the specific adsorption material captures more copper under the condition of similar copper release amount, which weakens the risk of endogenous pollution.

[0074] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and the present application can have various changes and variations for those skilled in the art; any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A preparation method of a specific adsorption material for solving heavy metal endogenous pollution in a water body, characterized in that, It comprises the following steps: S1, grinding natural clinoptilolite into powder after screening through 200 mesh sieve for standby; S2, weighing a certain amount of sieved zeolite, adding sodium hydroxide solution, continuously stirring under the action of constant temperature water bath, obtaining alkali modified zeolite, washing with deionized water and drying for standby; S3, adding alkali modified zeolite and chitosan into ice acetic acid solution according to a certain proportion, stirring for 1 h to make chitosan fully dissolved; S4, adding a certain amount of specific adsorption material in step S3 system, stirring for 1 h to make it fully mixed; The specific adsorption material is one of expanded vermiculite and corn straw biochar; S5, adding a certain amount of epichlorohydrin in step S4 system, stirring for 2 h to make it fully mixed; S6, using peristaltic pump to add the solution in step S5 system into a certain concentration of sodium tripolyphosphate solution at a constant speed, stirring for 3 h to make it fully mixed; S7, titrating step S6 system with standard sodium hydroxide solution and hydrochloric acid solution until its pH is 5, taking out the hydrogel beads after standing for a period of time and washing, drying to obtain specific ecological adsorption material.

2. The method according to claim 1, wherein the method is characterized by, In step S2, the amount of zeolite added is 20 g.

3. The method according to claim 1, wherein the method is characterized by, In step S2, the concentration of sodium hydroxide solution is 2 mol / l, the constant temperature water bath temperature is 75-85℃, and the stirring time is 7.5-8.5 h.

4. The method according to claim 1, wherein the method is characterized by, In step S3, the amount of chitosan added is 10 g, and the ice acetic acid solution is 100 ml with a volume fraction of 3%-5%.

5. The method according to claim 1, wherein the method is characterized by, The amount of specific adsorption material added is 10 g.

6. The method according to claim 1, wherein the method is characterized by, In step S5, the amount of epichlorohydrin added is 3 ml.

7. The method according to claim 1, wherein the method is characterized by, In step S6, the concentration of sodium tripolyphosphate solution is 20 g / l. 8.The method of claim 1, wherein the method is characterized by, In step S6, the speed of peristaltic pump is 2.5-3.5 r / min.

9. The method according to claim 1, wherein the method is characterized by, In step S7, the standing time is 2.5-3.5 h.

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