Silicate clay mixed medicament and preparation method thereof

Abstract

The invention relates to the technical field of water treatment agents, in particular to a silicate clay mixed agent and a preparation method thereof, and the preparation method comprises the following steps: firstly, anchoring iron-zirconium bimetal oxide on the surface and interlayer of silicate clay in situ in a nano active site form by adopting a coprecipitation-calcination process to form a stable load structure, thereby avoiding the loss of active components; secondly, nitrogen and sulfur co-doped carbon quantum dots are introduced as electron mediating bridges, so that adsorption and reaction kinetics are remarkably enhanced. Finally, the functional components are wrapped and bonded into stable microsphere particles by utilizing the cross-linking effect of cationic polysiloxane and aluminum dihydrogen phosphate in the curing process, so that the mechanical strength of the whole structure is enhanced, and the stability of the whole structure is improved through the charge neutralization and netting effects of the cationic polysiloxane. The synchronous deep removal of fluorine ions, heavy metals and organic pollutants is realized, and the long-term effect and stability of the medicament under the complex water quality condition are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment agents, in particular to a silicate clay mixed agent and a preparation method thereof. BACKGROUND

[0002] Industrial wastewater, especially wastewater generated in the metallurgical, electroplating, fluorine chemical and semiconductor industries, often contains high concentrations of fluoride ions, various heavy metal ions (such as chromium, copper, nickel, lead) and difficult-to-degrade organic pollutants. This kind of complexly contaminated wastewater is highly toxic and difficult to treat, and is a difficult point in water pollution control. The commonly used treatment technologies include chemical precipitation, coagulation and flocculation, adsorption, etc. The removal limit of fluoride by chemical precipitation (such as lime precipitation) is usually 15-20 mg / L, which is difficult to meet more stringent discharge standards (such as <10 mg / L), and the sludge production is large. Although a single adsorbent can remove fluoride deeply, it often has poor synergistic removal effect on heavy metals or organic matter when facing complex actual wastewater, and the cost is high.

[0003] To solve the above problems, a mixed agent, a preparation method and use thereof are disclosed in the patent document with publication number (CN116874058A), which is prepared by stirring and mixing silicate clay modified with aromatic heterocycle, phosphorus slag, calcium polysulfide, aluminum hydroxide and phytic acid. The mixed agent has good defluorination effect, decolorization effect and heavy metal ion removal effect. The present application also uses 4-methylsulfonyl benzyl alcohol as a modifier to prepare modified phytic acid for the preparation of the mixed agent, so that the mixed agent has better defluorination effect, decolorization effect and heavy metal ion removal effect.

[0004] However, the existing mixed agent for water treatment has limited synergistic effect due to physical mixing of various components, and it is difficult to achieve simultaneous and efficient deep removal of multiple pollutants. Moreover, the stability and long-term effectiveness of the agent are insufficient, and it is easy to fail under complex water quality conditions. SUMMARY

[0005] The present application aims to provide a silicate clay mixed agent and a preparation method thereof, which solves the problem of the existing mixed agent for water treatment, which has limited synergistic effect due to physical mixing of various components, and it is difficult to achieve simultaneous and efficient deep removal of multiple pollutants. Moreover, the stability and long-term effectiveness of the agent are insufficient, and it is easy to fail under complex water quality conditions.

[0006] To achieve the above-mentioned purpose, the present application provides a silicate clay mixed agent, which is composed of the following components in parts by mass: 400-600 parts of iron-zircon bimetallic oxide supported silicate clay; 30-80 parts of functionalized carbon quantum dots; 50-150 parts of cationic polysiloxane; ferrous sulfide 100-200 parts; aluminum dihydrogen phosphate 50-100 parts; The iron-zirconium bimetallic oxide loaded silicate clay is formed by in-situ loading iron-zirconium hydroxide on the surface and interlayer of silicate clay through coprecipitation method, and then converted by calcination; the functionalized carbon quantum dots are nitrogen-sulfur co-doped carbon quantum dots; the cationic polysiloxane is a polysiloxane polymer with quaternary ammonium salt groups on the side chain or at the end.

[0007] In the iron-zirconium bimetallic oxide loaded silicate clay, the molar ratio of iron element to zirconium element is 1:1 to 3:1; the silicate clay is purified sodium-based montmorillonite with a specific surface area of not less than 300 m 2 / g, or purified attapulgite with an aspect ratio of not less than 10; the iron-zirconium bimetallic oxide is distributed on the silicate clay carrier in the form of nanoparticles or amorphous film.

[0008] In the functionalized carbon quantum dots, the average particle size is between 2-8 nanometers, and the surface of the functionalized carbon quantum dots contains both amino groups and sulfonic acid groups, and the molar ratio of amino groups to sulfonic acid groups is between 1:2 and 2:1.

[0009] In the cationic polysiloxane, the number average molecular weight is 2000-10000, and the quaternization degree is not less than 50%; the purity of the ferrous sulfide powder is not less than 90%, and the particle size distribution D90 is less than 45 microns.

[0010] The application also provides a preparation method of a silicate clay mixed agent, for preparing the silicate clay mixed agent as described above, comprising the following steps: Preparation of the functionalized carbon quantum dots: nitrogen-sulfur co-doped carbon quantum dots are synthesized by hydrothermal method using citric acid and L-cysteine as precursors, and solid products are obtained by dialysis and freeze-drying; Preparation of the iron-zirconium bimetallic oxide loaded silicate clay: the silicate clay is dispersed in water, and a mixed solution of iron salt and zirconium salt is introduced, and stable iron-zirconium bimetallic oxide active sites are formed on the surface and interlayer of the clay through alkali co-precipitation and subsequent calcination; Dry pre-mixing: the iron-zirconium bimetallic oxide loaded silicate clay and the functionalized carbon quantum dots are mixed at high speed to prepare a pre-mix A; Liquid phase composite granulation: the cationic polysiloxane is diluted with ethanol, mixed with an aqueous solution of aluminum dihydrogen phosphate to form a liquid phase bonding system, and introduced into the mixture of pre-mix A and the ferrous sulfide powder by spraying, and the wetting, compounding and granulation processes are completed in a dynamic granulation device to obtain homogeneous wet granules; The obtained wet granules are subjected to a stepwise low-temperature curing treatment with programmed temperature rising, and finally the silicate clay composite agent is obtained.

[0011] The functionalized carbon quantum dots are prepared by mixing citric acid and L-cysteine in a mass ratio of 1.5:1-3:1, dissolving them in deionized water to prepare a precursor solution with a concentration of 0.05-0.15 g / mL, and then subjecting the solution to hydrothermal reaction at 160-200 ℃ for 4-8 hours. The reaction product is purified, freeze-dried, and then the nitrogen-sulfur co-doped carbon quantum dots are obtained.

[0012] The functionalized carbon quantum dots are prepared by mixing citric acid and L-cysteine in a mass ratio of 1.5:1-3:1, dissolving them in deionized water to prepare a precursor solution with a concentration of 0.05-0.15 g / mL, and then subjecting the solution to hydrothermal reaction at 160-200 ℃ for 4-8 hours. The reaction product is purified, freeze-dried, and then the nitrogen-sulfur co-doped carbon quantum dots are obtained. The purified silicate clay is dispersed in deionized water; A mixed salt solution with a total metal ion concentration of 0.3-0.8 mol / L and a molar ratio of iron to zirconium of 1:1-3:1 is prepared; The mixed salt solution is added to the clay suspension under stirring, and then a co-precipitation reaction is carried out by adjusting the pH of the system to 9-11 using a 1-3 mol / L alkaline precipitant; After the reaction is completed, the system is aged at 50-70 ℃ for 6-12 hours. The obtained product is washed and dried, and then calcined at 400-500 ℃ for 2-4 hours to obtain the iron-zirconium bimetallic oxide loaded silicate clay.

[0013] In the step of dry pre-mixing, the high-speed shearing mixing is carried out at a speed of 1000-3000 rpm for 10-30 minutes.

[0014] In the step of liquid-phase composite granulation, the liquid-phase binding system is prepared by mixing the cationic polysiloxane diluted with ethanol and an aqueous solution of aluminum dihydrogen phosphate with a mass concentration of 40%-60%. The granulation process is carried out in a fluidized bed or a high-speed stirring granulator, and the spray pressure is controlled at 0.2-0.4 MPa to make the liquid-phase binding system and the solid powder composite to form wet granules with a particle size of 0.5-3 mm.

[0015] The silicate clay mixed agent and the preparation method thereof provided by the application comprise iron-zirconium bimetallic oxide loaded silicate clay, functionalized carbon quantum dots, cationic polysiloxane, ferrous sulfide and aluminum dihydrogen phosphate. First, the iron-zirconium bimetallic oxide is in-situ anchored on the surface and interlayer of the silicate clay in the form of nano active sites by using the co-precipitation-calcination process, so as to form a stable loading structure and avoid the loss of active components. Second, the nitrogen-sulfur co-doped carbon quantum dots are introduced as an electronic mediation bridge, which significantly enhances the adsorption and reaction kinetics. Finally, the functional components are wrapped and bonded into stable microspheres by using the cross-linking effect of the cationic polysiloxane and the aluminum dihydrogen phosphate in the curing process, which not only strengthens the mechanical strength of the overall structure, but also realizes the synchronous deep removal of fluoride ions, heavy metals and organic pollutants through the charge neutralization and net capture of the cationic polysiloxane, thereby ensuring the long-term effectiveness and stability of the agent under complex water quality conditions. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0017] Figure 1 It is a step flow chart of the preparation method of the silicate clay mixed agent provided by the present application.

[0018] Figure 2 It is a step flow chart of the preparation method of the iron-zirconium bimetallic oxide loaded silicate clay provided by the present application. DETAILED DESCRIPTION

[0019] The embodiments of the present application will be described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0020] The present application provides a silicate clay mixed agent, which is composed of the following components in parts by mass: Iron-zirconium bimetallic oxide loaded silicate clay 400-600 parts; Functionalized carbon quantum dots 30-80 parts; Cationic polysiloxane 50-150 parts; Ferrous sulfide 100-200 parts; Aluminum dihydrogen phosphate 50-100 parts; The iron-zirconium bimetallic oxide loaded silicate clay is formed by in-situ loading iron-zirconium hydroxide on the surface and interlayer of silicate clay through coprecipitation method, and then converting through calcination; the functionalized carbon quantum dots are nitrogen-sulfur co-doped carbon quantum dots; and the cationic polysiloxane is a polysiloxane polymer with quaternary ammonium salt groups on the side chain or at the end.

[0021] In the embodiment, first, iron-zirconium bimetallic oxide is in-situ anchored on the surface and interlayer of silicate clay in the form of nano active sites by using a coprecipitation-calcination process to form a stable loading structure, avoiding the loss of active components. Second, nitrogen-sulfur co-doped carbon quantum dots are introduced as an electronic mediation bridge to significantly enhance the adsorption and reaction kinetics. Finally, the cross-linking of the cationic polysiloxane and aluminum dihydrogen phosphate in the curing process wraps and bonds each functional component into a stable microsphere particle, not only strengthening the mechanical strength of the overall structure, but also realizing the simultaneous deep removal of fluoride ions, heavy metals and organic pollutants through the charge neutralization and net capture of the cationic polysiloxane, ensuring the long-acting and stability of the medicament under complex water quality conditions.

[0022] Further, in the iron-zirconium bimetallic oxide loaded silicate clay, the molar ratio of iron to zirconium is 1:1 to 3:1; the silicate clay is purified sodium-based montmorillonite with a specific surface area of not less than 300 m 2 / g, or purified attapulgite with an aspect ratio of not less than 10; and the iron-zirconium bimetallic oxide is distributed on the silicate clay carrier in the form of nanoparticles or amorphous film.

[0023] In the embodiment, the molar ratio of iron to zirconium is limited to 1:1 to 3:1 to optimize the ratio of active sites; sodium-based montmorillonite with high specific surface area or attapulgite with high aspect ratio is selected as the carrier to greatly increase the reaction contact area; and iron-zirconium oxide is highly dispersed on the carrier in the form of nanoparticles or amorphous film to maximize the exposure of active sites.

[0024] Further, the average particle size of the functionalized carbon quantum dots is between 2-8 nanometers, and the surface of the functionalized carbon quantum dots contains both amino and sulfonic acid functional groups, wherein the molar ratio of amino to sulfonic acid is between 1:2 and 2:1.

[0025] In the embodiment, the ultra-fine particle size provides a large specific surface area and a large number of surface active sites, and the specific ratio of amino groups (positively charged, used for adsorbing anionic pollutants and complexing heavy metals) and sulfonic acid groups (negatively charged, used for adsorbing cations and enhancing hydrophilicity) together realize the broad-spectrum adsorption and synergistic removal of different electrically charged pollutants, thereby effectively improving the purification efficiency and stability of the medicament under complex water quality conditions.

[0026] Further, the cationic polysiloxane has a number average molecular weight of 2000-10000 and a quaternization degree of not less than 50%; the ferrous sulfide powder has a purity of not less than 90% and a particle size distribution D90 of less than 45 microns.

[0027] In the embodiment, the number average molecular weight (2000-10000) and the quaternization degree (≥50%) of the cationic polysiloxane are limited to ensure that the cationic polysiloxane has good chain length and strong cationic characteristics and can effectively play the charge neutralization and net capture flocculation effect; at the same time, the high purity (≥90%) and fine particle size (D90 < 45 μm) of the ferrous sulfide are controlled to ensure the high reactivity and uniform dispersibility of the ferrous sulfide in the medicament.

[0028] Referring to Figure 1 and Figure 2 , the application further provides a preparation method of the silicate clay mixed medicament, for preparing the silicate clay mixed medicament as described above, comprising the following steps: S1, preparing the functionalized carbon quantum dots: using citric acid and L-cysteine as precursors, nitrogen and sulfur co-doped carbon quantum dots are synthesized by a hydrothermal method, and a solid product is obtained by dialysis and freeze-drying; S2, preparing the iron-zirconium bimetallic oxide loaded silicate clay: dispersing the silicate clay in water, introducing a mixed solution of iron salt and zirconium salt, forming stable iron-zirconium bimetallic oxide active sites on the surface and interlayer of the clay through alkali co-precipitation and subsequent calcination; S3, dry premixing: high-speed shearing mixing the iron-zirconium bimetallic oxide loaded silicate clay and the functionalized carbon quantum dots dry powder to prepare a premix A; S4, implementing liquid phase composite granulation: diluting the cationic polysiloxane with ethanol, mixing the diluted cationic polysiloxane with an aqueous solution of aluminum dihydrogen phosphate to form a liquid phase bonding system, and introducing the liquid phase bonding system into the mixture of the premix A and the ferrous sulfide by spraying, completing the wetting, compounding and granulation process in a dynamic granulation device to obtain homogeneous wet granules; S5, completing solidification and shaping: performing a programmed temperature rising stepwise low temperature solidification treatment on the obtained wet granules to finally obtain the silicate clay composite medicament.

[0029] In the embodiment, the method first prepares the functionalized carbon quantum dots and the structurally stable clay matrix (the iron-zirconium bimetallic oxide loaded silicate clay) by hydrothermal method and co-precipitation-calcination respectively; then the functionalized carbon quantum dots are uniformly dispersed and attached to the surface of the matrix by dry pre-mixing to realize the micro combination between components; further, all components are compounded into homogeneous particles in dynamic granulation by using a liquid phase bonding system, and the components are cross-linked and bonded into a stable whole through the final step of staged low-temperature curing. The process flow ensures the high dispersion, close compounding and structural stability of the functional components, thereby significantly improving the synergistic purification effect and service life of the medicament.

[0030] Further, the specific content of the step of preparing the functionalized carbon quantum dots is that citric acid and L-cysteine are mixed in a mass ratio of 1.5:1-3:1, dissolved in deionized water to prepare a precursor solution with a concentration of 0.05-0.15 g / mL, and then subjected to hydrothermal reaction at 160-200°C for 4-8 hours. The reaction product is purified and freeze-dried to obtain the nitrogen-sulfur co-doped carbon quantum dots.

[0031] Further, the specific content of the step of preparing the iron-zirconium bimetallic oxide loaded silicate clay is as follows: S101: dispersing the purified silicate clay in deionized water; S102: preparing a mixed salt solution with a total metal ion concentration of 0.3-0.8 mol / L and a molar ratio of iron to zirconium of 1:1-3:1; S103: adding the mixed salt solution to the clay suspension under stirring, and then adjusting the pH of the system to 9-11 with a 1-3 mol / L alkaline precipitant for co-precipitation reaction; S104: after the reaction is completed, aging at 50-70°C for 6-12 hours, and then washing, drying, and calcining the obtained product at 400-500°C for 2-4 hours to obtain the iron-zirconium bimetallic oxide loaded silicate clay.

[0032] Further, in the step of dry pre-mixing, the high-speed shearing mixing conditions are as follows: mixing at a speed of 1000-3000 rpm for 10-30 minutes.

[0033] Further, in the step of liquid phase compounding and granulation, the liquid phase bonding system is prepared by mixing the cationic polysiloxane diluted with ethanol and the water solution of aluminum dihydrogen phosphate with a mass concentration of 40%-60%; the granulation process is completed in a fluidized bed or a high-speed stirring granulator, and the spray pressure is controlled at 0.2-0.4 MPa to make the liquid phase bonding system and the solid powder compound into wet particles with a particle size of 0.5-3 mm.

[0034] In the embodiment, by limiting the precursor ratio, concentration and reaction conditions of hydrothermal synthesis of carbon quantum dots, the controllability of nanostructure and surface functional groups is ensured; by optimizing the ion concentration, ratio, pH and subsequent calcination system of the coprecipitation process, high activity and stable loading of iron-zirconium oxide on clay are realized; by setting the rotation speed and time of dry pre-mixing, the uniform dispersion and interface combination of nano components on the matrix are promoted; finally, by limiting the composition, granulation equipment and spray pressure of the liquid phase bonding system, uniform wrapping and stable forming of all components are realized, forming composite medicament particles with uniform size and dense structure. This set of precisely controllable preparation process jointly ensures the reliable realization of high efficiency and stable performance of the medicament.

[0035] The above only discloses a preferred embodiment of the present application, of course cannot limit the scope of the present application, those skilled in the art can understand that the above-mentioned embodiment can realize all or part of the process, and the equivalent changes made according to the claims of the present application still belong to the scope covered by the present application.

Claims

1. A silicate clay mixed agent, characterized in that, in terms of mass fraction, it is composed of: 400-600 parts of silicate clay loaded with iron-zirconium bimetallic oxide; 30-80 parts of functionalized carbon quantum dots; 50-150 parts of cationic polysiloxane; and 100-200 parts of ferrous sulfide; and 50-100 parts of aluminum dihydrogen phosphate. 2.The silicate clay mixed agent of claim 1, characterized in that, the silicate clay loaded with iron-zirconium bimetallic oxide is formed by in-situ loading iron-zirconium hydroxide on the surface and interlayer of silicate clay through coprecipitation method, and then being converted by calcination; the functionalized carbon quantum dots are nitrogen-sulfur co-doped carbon quantum dots; and the cationic polysiloxane is a polysiloxane polymer with quaternary ammonium salt groups on the side chain or at the end. 3.The silicate clay mixed agent of claim 2, characterized in that, the average particle size of the functionalized carbon quantum dots is between 2-8 nanometers, and the surface of the functionalized carbon quantum dots contains both amino and sulfonic acid functional groups, wherein the molar ratio of amino to sulfonic acid is between 1:2 and 2:

1. 4.The silicate clay mixed agent of claim 3, characterized in that, the number average molecular weight of the cationic polysiloxane is 2000-10000, and the degree of quaternization is not less than 50%; and the purity of the ferrous sulfide powder is not less than 90%, and the particle size distribution D90 is less than 45 microns. 5.A preparation method of the silicate clay mixed agent of claim 1, comprising the following steps: preparing the functionalized carbon quantum dots: using citric acid and L-cysteine as precursors, synthesizing nitrogen-sulfur co-doped carbon quantum dots by hydrothermal method, and obtaining solid product through dialysis and freeze-drying; preparing the silicate clay loaded with iron-zirconium bimetallic oxide: dispersing silicate clay in water, introducing iron salt and zirconium salt mixed solution, forming stable iron-zirconium bimetallic oxide active sites on the surface and interlayer of the clay through alkali co-precipitation and subsequent calcination; carrying out dry premixing: high-speed shearing mixing the silicate clay loaded with iron-zirconium bimetallic oxide and the functionalized carbon quantum dots dry powder to prepare premix A; implementing liquid phase composite granulation: diluting the cationic polysiloxane with ethanol, mixing with the aqueous solution of aluminum dihydrogen phosphate to form a liquid phase bonding system, and introducing it into the mixture of premix A and the ferrous sulfide powder by spraying, completing the wetting, compounding and granulation process in a dynamic granulation device to obtain homogeneous wet granules; completing solidification and shaping: carrying out programmed temperature stepwise low temperature solidification treatment on the obtained wet granules to finally obtain the silicate clay composite agent. 6.The preparation method of the silicate clay mixed agent of claim 5, characterized in that, the specific content of the step of preparing the functionalized carbon quantum dots is: mixing citric acid and L-cysteine at a mass ratio of 1.5:1-3:1, dissolving in deionized water to prepare a precursor solution with a concentration of 0.05-0.15 g / mL, and carrying out hydrothermal reaction at 160-200 ℃ for 4-8 hours, and then freeze-drying the reaction product to obtain the nitrogen-sulfur co-doped carbon quantum dots. ​ ​ ​ The molar ratio of iron element to zirconium element in the iron-zirconium bimetallic oxide loaded silicate clay is 1:1 to 3:1; the silicate clay is purified sodium-based montmorillonite with a specific surface area of not less than 300 m 2 / g, or purified attapulgite with an aspect ratio of not less than 10; the iron-zirconium bimetallic oxide is distributed on the silicate clay carrier in the form of nanoparticles or amorphous thin films. ​ ​ ​ ​ 5. A method for preparing a silicate clay complexing agent for use in the preparation of a silicate clay complexing agent as claimed in claim 1, characterised in that, ​ ​ ​ ​ ​ ​ ​ ​ 7. The method according to claim 6, wherein the preparation of the silicate clay mixed agent is characterized in that, The specific content of the step of preparing the iron-zirconium bimetallic oxide loaded silicate clay is: The purified silicate clay is dispersed in deionized water; A mixed salt solution is prepared, with a total metal ion concentration of 0.3-0.8 mol / L and a molar ratio of iron to zirconium of 1:1-3:1; The mixed salt solution is added to the clay suspension under stirring, followed by adjusting the pH of the system to 9-11 with a 1-3 mol / L alkaline precipitant for co-precipitation reaction; After the reaction is completed, the obtained product is washed and dried, and then calcined at 400-500°C for 2-4 hours to obtain the iron-zirconium bimetallic oxide loaded silicate clay.

8. The method according to claim 7, wherein in the step of dry pre-mixing, the high-speed shearing mixing is performed at a speed of 1000-3000 rpm for 10-30 minutes.

9. The method according to claim 8, wherein in the step of liquid-phase complex granulation, the liquid-phase binding system is prepared by mixing the cationic polysiloxane diluted with ethanol with an aqueous solution of aluminum dihydrogen phosphate with a mass concentration of 40%-60%; the granulation process is completed in a fluidized bed or a high-speed stirring granulator, and the spraying pressure is controlled at 0.2-0.4 MPa to make the liquid-phase binding system and the solid powder complex to form wet granules with a particle size of 0.5-3 mm. ​ ​

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