Environmentally friendly fluorine- and heavy metal-containing water treatment agent and preparation method thereof

Abstract

The present invention belongs to the technical field of wastewater treatment, and specifically refers to an environmentally friendly fluorine-containing and heavy metal water treatment agent and a preparation method thereof, wherein the environmentally friendly fluorine-containing and heavy metal water treatment agent includes the following raw materials in parts by weight: 8-12 parts of calcium carbide waste residue, 5.5-7.5 parts of clay modifier, 8 parts of gel base material, 1-2 parts of PVP, 0.5-1.5 parts of polyacrylamide and 0.1-0.3 parts of polyoxymethylene fiber; the present invention takes calcium carbide waste residue as the core, and its alkalinity can realize calcium fluoride precipitation, heavy metal adsorption and wastewater neutralization; straw powder and citric acid modified clay form a porous structure and Lewis acid sites, thereby enhancing heavy metal adsorption; Fe3O4 generates a flocculent gel under alkalinity, and forms a crystalline phase with clay to enhance strength; chitosan-modified diatomaceous earth composite gel base promotes ion diffusion, prevents pore clogging, and stabilizes the structure; the agent is low-cost and highly stable, and can simultaneously and deeply remove fluorine and heavy metals.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and specifically relates to an environmentally friendly fluorine- and heavy metal-containing water treatment agent and a preparation method thereof. Background Art

[0002] With the rapid development of industry, the problem of fluorine and heavy metal wastewater discharge is becoming increasingly serious.

[0003] At present, although the chemical precipitation method of existing technology can remove some pollutants, it has problems such as large dosage of reagents, large amount of sludge generated, and high risk of secondary pollution; although the adsorption method has better effect, the adsorption material cost is high and regeneration is difficult, and some adsorbents lack mechanical strength and are easily worn and deactivated during the treatment process; the ion exchange method has high selectivity for specific ions, but the resin is easily contaminated and has a short service life.

[0004] Therefore, developing an environmentally friendly, efficient, low-cost water treatment agent that can simultaneously remove fluorine and heavy metals has become an urgent need to solve the problem of wastewater pollution. Summary of the Invention

[0005] In response to the defects of the existing technology, the present invention discloses an environmentally friendly fluorine-containing and heavy metal water treatment agent, which takes calcium carbide waste residue as the core. Its alkaline environment simultaneously drives calcium fluoride precipitation and heavy metal adsorption, and neutralizes acidic wastewater; uses straw powder to form pores and citric acid to induce oxygen defects, constructs a porous structure and Lewis acid sites in the clay modification, and greatly improves the heavy metal coordination adsorption capacity; introduces Fe3O4 to generate iron hydroxide colloid under alkaline conditions to strengthen flocculation, and forms an iron aluminum silicate crystal phase with clay to enhance mechanical stability; adopts chitosan-modified diatomaceous earth composite gel base, accelerates ion diffusion through hydrophilic groups, inhibits CaF2 grains from clogging pores, and stabilizes the structure by cross-linking with Fe-O-Si covalent bonds and hydrogen bonds, reducing the loss of active sites; ultimately, low-cost, high-stability simultaneous deep removal of fluorine / heavy metals is achieved.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is an environmentally friendly fluorine- and heavy metal-containing water treatment agent, which includes the following raw materials in parts by weight: 8-12 parts of calcium carbide waste residue, 5.5-7.5 parts of clay modifier, 8 parts of gel-based material, 1-2 parts of PVP, 0.5-1.5 parts of polyacrylamide and 0.1-0.3 parts of polyoxymethylene fiber.

[0007] Furthermore, the preparation method of the clay modification comprises the following steps:

[0008] A. Weigh 6-8 parts of clay and sieve them through a 200-mesh sieve, 0.5-1 parts of citric acid, and 0.8 parts of straw powder and sieve them through a 200-mesh sieve. Mill the above materials in a ball mill at 200 rpm for 30 minutes to obtain a calcined precursor.

[0009] B. calcining the precursor obtained in step A at 450° C. for 2.5 h at a heating rate of 10° C. / min, introducing argon gas at a flow rate of 300 mL / min during the calcination process, and then naturally cooling to room temperature to obtain calcined product I;

[0010] C. Weigh 1-3 parts of Fe3O4 and add it to the calcined product I obtained in step B. Ball mill the product for 30 min at a speed of 200 r / min, and then perform a secondary calcination at 800°C for 3 h. The heating rate of the secondary calcination process is 5°C / min. During the secondary calcination process, argon gas is introduced at a flow rate of 300 mL / min. The product is then naturally cooled to room temperature and washed alternately with deionized water and ethanol three times each to obtain a clay modified product.

[0011] Furthermore, the preparation method of the gel-based substrate comprises the following steps:

[0012] α weighed 4-7 parts of chitosan was added to 15 parts of a 0.1mol / L acetic acid solution, stirred at a speed of 500r / min for 30min to obtain acetic acid activation;

[0013] β. Weigh 2.5 modified diatomaceous earth and add the acetic acid activated product obtained in step α, stir at a speed of 500r / min for 30min, then continue to weigh 1.2 parts of ethylene glycol and 1-3 parts of ethanol and add them, let stand for 4h in a water bath at 50 ° C, and cool naturally to room temperature to obtain a gel precursor;

[0014] γ. The gel precursor obtained in step β is placed in a low temperature condition of -5°C for curing for 24 hours, and then crushed into particles with a particle size of 1.5 mm, and dried at a temperature of 65°C for 48 hours to obtain a gel-based material.

[0015] Furthermore, the preparation method of the modified diatomite comprises the following steps:

[0016] S1. Weigh 15-25 parts of diatomaceous earth and sieve it through a 200-mesh screen. Then add it to 30 parts of deionized water and stir it at 500 r / min for 30 minutes. Then add 1-2 parts of hydrogen peroxide. Heat it in a water bath at 40°C for 2 hours while stirring at 500 r / min. Then, centrifuge it at 8000 r / min for 10 minutes to obtain oxidized diatomaceous earth.

[0017] S2. The oxidized diatomaceous earth obtained in step S1 was added to 20 parts of ethanol and stirred at a speed of 500 r / min for 20 minutes. 3.5-5 parts of a silane coupling agent and 0.3 parts of sodium dodecyl sulfate were weighed and added thereto. The mixture was stirred at a speed of 500 r / min for 1 hour. The mixture was washed alternately with deionized water and ethanol three times each to obtain modified diatomaceous earth.

[0018] The present invention also provides a method for preparing an environmentally friendly fluorine- and heavy metal-containing water treatment agent, comprising the following steps:

[0019] Step 1. Weigh 8-12 parts of calcium carbide waste residue and sieve it under a 100-mesh screen, then add 25 parts of acetic acid solution, wherein the concentration of acetic acid solution is 0.25mol / L, ultrasonically treated at a power of 40kHz for 20min, and then centrifuged at a speed of 8000r / min for 10min to obtain a waste residue activation product;

[0020] Step 2. Weigh 5.5-7.5 parts of the clay modifier and 8 parts of the gel base material and add 15 parts of an ethanol solution, wherein the ethanol solution is a mixed solution of ethanol and water in a mass percentage of 70:30, and stir at a speed of 500 r / min for 40 min to obtain a paste;

[0021] Step 3. Weigh 1-2 parts of PVP and 0.1-0.3 parts of polyoxymethylene fiber and add them to 10 parts of deionized water, ultrasonicate at a power of 40kHz for 20 minutes, and then stir at a speed of 500r / min for 30 minutes to obtain a pre-reaction liquid. Add the activated waste residue obtained in step 1 to the pre-reaction liquid and heat it at a temperature of 60°C for 2 hours. Continue to add 0.5-1.5 parts of polyacrylamide and the paste obtained in step 2, ultrasonicate at a power of 40kHz for 15 minutes, and then stir at a speed of 500r / min for 30 minutes. Dry it at a temperature of 80°C for 24 hours and crush it into particles with a particle size of 2 mm to obtain an environmentally friendly fluorine-containing and heavy metal water treatment agent.

[0022] The beneficial effects achieved by the present invention are as follows:

[0023] The environmentally friendly fluorine-containing and heavy metal water treatment agent prepared by the present invention uses calcium carbide waste residue as the main material, and obtains alkaline hydroxide through reaction with F in water. - The formation of precipitation, and the alkalinity of calcium carbide waste residue can neutralize acidic wastewater, creating a suitable alkaline environment for the adsorption of heavy metals; further, straw powder is used as a pore-forming agent and co-calcined with clay to prepare a porous adsorption material, which provides more active sites for the treatment process of wastewater materials, and citric acid is introduced to induce the generation of oxygen defects by high-temperature calcination. Oxygen defects act as Lewis acid sites and form coordination bonds with heavy metal ions, providing more active sites for the adsorption of heavy metals; in addition, the added Fe3O4 can be partially dissolved in an alkaline environment to generate Fe 2+ / Fe 3+ , and OH in carbide waste slag - It combines to form iron hydroxide colloid, which adsorbs heavy metal ions through flocculation, further improving the removal efficiency. During the calcination process, Fe3O4 and silicate minerals in the clay form composite crystalline iron aluminum silicate, which improves the mechanical strength of the material and reduces the loss of active sites caused by wear during the adsorption process.

[0024] The environmentally friendly fluorine-containing and heavy metal-containing water treatment agent prepared by the present invention uses chitosan and modified diatomaceous earth as composite gel base materials to deposit the composite material of calcium carbide waste slag and clay modification. The hydrophilic groups (-OH / -NH2) in the gel network improve the dispersibility of calcium carbide waste slag particles and accelerate OH - Diffusion into the solution, strengthening Ca 2+ With F - The gel network restrains the calcium carbide waste slag particles, prevents pore blockage caused by excessive grain growth during CaF2 precipitation, and maintains the permeability of the material; in addition, Fe3O4 is embedded in the diatomaceous earth skeleton through Fe-O-Si covalent bonds, and the siliceous skeleton of the diatomaceous earth and the Fe3O4 silicate composite crystal phase work synergistically to reduce particle breakage and active site loss caused by mechanical stirring or water flow impact during the adsorption process. The microporous structure of the diatomaceous earth adsorbs chitosan molecular chains to form cross-linking points, inhibits excessive swelling of the gel, and forms hydrogen bonds with chitosan hydroxyl groups through silicon hydroxyl groups to enhance cross-linking.

[0025] The environmentally friendly fluorine- and heavy metal-containing water treatment agent prepared by the present invention focuses on environmental protection, high efficiency and low cost as research priorities, and can better meet the needs of wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a diagram of the preparation method of the environmentally friendly fluorine-containing and heavy metal water treatment agent proposed by the present invention;

[0027] Figure 2 is the SEM image of the unmodified clay in Example 2;

[0028] Figure 3 TEM image of the modified clay prepared in Example 2;

[0029] Figure 4 The EPR graphs of the clay prepared in Example 2 before and after modification (calcination);

[0030] Figure 5 The environmentally friendly fluorine-containing and heavy metal water treatment agent F prepared in the examples and comparative examples - Remove the graph;

[0031] Figure 6 This is a diagram showing the adsorption of heavy metals by the environmentally friendly fluorine-containing and heavy metal-containing water treatment agents prepared in the examples and comparative examples.

[0032] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0035] The preparation methods in the following examples are based on the relevant test results. Figures 1-6 Unless otherwise specified, all methods are conventional; the materials used in the following examples, unless otherwise specified, are parts by mass in the present invention, and all ethanol concentrations involved are 99.8%.

[0036] Example 1: An environmentally friendly fluorine- and heavy metal-containing water treatment agent comprises the following raw materials in parts by weight: 8 parts of calcium carbide waste residue, 5.5 parts of clay modification, 8 parts of gel-based material, 1 part of PVP, 0.5 parts of polyacrylamide and 0.1 parts of polyoxymethylene fiber.

[0037] The preparation method of the clay modified material comprises the following steps:

[0038] A. Weigh 6 parts of clay and sieve them through a 200-mesh sieve, 0.5 parts of citric acid, and 0.8 parts of straw powder and sieve them through a 200-mesh sieve. Then, ball mill the above materials at a speed of 200 r / min for 30 minutes to obtain a calcined precursor.

[0039] B. calcining the precursor obtained in step A at 450° C. for 2.5 h at a heating rate of 10° C. / min, introducing argon gas at a flow rate of 300 mL / min during the calcination process, and then naturally cooling to room temperature to obtain calcined product I;

[0040] C. Weigh 1 part of Fe3O4 and add it to the calcined product I obtained in step B. Ball mill the product for 30 min at a speed of 200 r / min, then perform a secondary calcination at 800°C for 3 h. The heating rate of the secondary calcination process is 5°C / min. During the secondary calcination process, argon gas is introduced at a flow rate of 300 mL / min. The product is then naturally cooled to room temperature and washed alternately with deionized water and ethanol three times each to obtain a clay modified product.

[0041] The preparation method of the gel-based substrate comprises the following steps:

[0042] α weighed 4 parts of chitosan was added to 15 parts of a 0.1mol / L acetic acid solution, stirred at a speed of 500r / min for 30min to obtain acetic acid activation;

[0043] β. Weigh 2.5 modified diatomaceous earth and add the acetic acid activated product obtained in step α, stir at a speed of 500r / min for 30min, then continue to weigh 1.2 parts of ethylene glycol and 1 part of ethanol and add them, let stand for 4h in a water bath at 50 ° C, and cool naturally to room temperature to obtain a gel precursor;

[0044] γ. The gel precursor obtained in step β is placed in a low temperature condition of -5°C for curing for 24 hours, and then crushed into particles with a particle size of 1.5 mm, and dried at a temperature of 65°C for 48 hours to obtain a gel-based material.

[0045] The preparation method of modified diatomaceous earth comprises the following steps:

[0046] S1. 15 parts of diatomaceous earth were weighed and sieved through a 200-mesh sieve. The mixture was then added to 30 parts of deionized water and stirred at 500 r / min for 30 minutes. 1 part of hydrogen peroxide was then added to the mixture. The mixture was heated in a water bath at 40°C for 2 hours while stirring at 500 r / min. The mixture was then centrifuged at 8000 r / min for 10 minutes to obtain oxidized diatomaceous earth.

[0047] S2. The oxidized diatomaceous earth obtained in step S1 was added to 20 parts of ethanol and stirred at a speed of 500 r / min for 20 minutes. 3.5 parts of a silane coupling agent and 0.3 parts of sodium dodecyl sulfate were weighed and added thereto. The mixture was stirred at a speed of 500 r / min for 1 hour. The mixture was washed alternately with deionized water and ethanol three times each to obtain modified diatomaceous earth.

[0048] This embodiment also provides a method for preparing an environmentally friendly fluorine- and heavy metal-containing water treatment agent, comprising the following steps:

[0049] Step 1. Weigh 8 parts of calcium carbide waste residue and sieve it under a 100-mesh screen, then add 25 parts of acetic acid solution, wherein the concentration of acetic acid solution is 0.25mol / L, ultrasonically treated at a power of 40kHz for 20min, and then centrifuged at a speed of 8000r / min for 10min to obtain a waste residue activation product;

[0050] Step 2. Weigh 5.5 parts of the clay modifier and 8 parts of the gel base material and add 15 parts of an ethanol solution, wherein the ethanol solution is a mixed solution of ethanol and water in a mass percentage of 70:30, and stir at a speed of 500 r / min for 40 min to obtain a paste;

[0051] Step 3. Weigh 1 part of PVP and 0.1 part of polyoxymethylene fiber and add them to 10 parts of deionized water, ultrasonicate at a power of 40kHz for 20 minutes, and then stir at a speed of 500r / min for 30 minutes to obtain a pre-reaction liquid. Add the activated waste residue obtained in step 1 to the pre-reaction liquid and heat it at a temperature of 60°C for 2 hours. Continue to add 0.5 parts of polyacrylamide and the paste obtained in step 2, ultrasonicate at a power of 40kHz for 15 minutes, and then stir at a speed of 500r / min for 30 minutes. Dry it at a temperature of 80°C for 24 hours and crush it into particles with a particle size of 2 mm to obtain an environmentally friendly fluorine-containing and heavy metal water treatment agent.

[0052] Example 2: An environmentally friendly fluorine- and heavy metal-containing water treatment agent comprises the following raw materials in parts by weight: 10 parts of calcium carbide waste residue, 6.5 parts of clay modification, 8 parts of gel-based material, 1.5 parts of PVP, 1 part of polyacrylamide and 0.2 parts of polyoxymethylene fiber.

[0053] The preparation method of the clay modified material comprises the following steps:

[0054] A. Weigh 7 parts of clay and sieve them through a 200-mesh sieve, 0.8 parts of citric acid, and 0.8 parts of straw powder and sieve them through a 200-mesh sieve. Then, ball mill the above materials at a speed of 200 r / min for 30 minutes to obtain a calcined precursor.

[0055] B. calcining the precursor obtained in step A at 450° C. for 2.5 h at a heating rate of 10° C. / min, introducing argon gas at a flow rate of 300 mL / min during the calcination process, and then naturally cooling to room temperature to obtain calcined product I;

[0056] C. Weigh 2 parts of Fe3O4 and add them to the calcined product I obtained in step B. Ball mill the product for 30 min at a speed of 200 r / min, and then perform a secondary calcination at 800°C for 3 h. The heating rate of the secondary calcination process is 5°C / min. During the secondary calcination process, argon gas is introduced at a flow rate of 300 mL / min. The product is then naturally cooled to room temperature and washed alternately with deionized water and ethanol three times each to obtain a clay modified product.

[0057] The preparation method of the gel-based substrate comprises the following steps:

[0058] α weighed 5.5 parts of chitosan was added to 15 parts of a 0.1mol / L acetic acid solution, stirred at a speed of 500r / min for 30min to obtain acetic acid activated;

[0059] β. Weigh 2.5 modified diatomaceous earth and add the acetic acid activated product obtained in step α, stir at a speed of 500r / min for 30min, then continue to weigh 1.2 parts of ethylene glycol and 2 parts of ethanol and add them, let stand for 4h in a water bath at 50 ° C, and cool naturally to room temperature to obtain a gel precursor;

[0060] γ. The gel precursor obtained in step β is placed in a low temperature condition of -5°C for curing for 24 hours, and then crushed into particles with a particle size of 1.5 mm, and dried at a temperature of 65°C for 48 hours to obtain a gel-based material.

[0061] The preparation method of modified diatomaceous earth comprises the following steps:

[0062] S1. Weigh 20 parts of diatomaceous earth and sieve it through a 200-mesh sieve. Then add it to 30 parts of deionized water and stir it at 500 r / min for 30 minutes. Then add 1.5 parts of hydrogen peroxide. Heat it in a water bath at 40°C for 2 hours while stirring at 500 r / min. Then, centrifuge it at 8000 r / min for 10 minutes to obtain oxidized diatomaceous earth.

[0063] S2. The oxidized diatomaceous earth obtained in step S1 was added to 20 parts of ethanol and stirred at a speed of 500 r / min for 20 minutes. 4.3 parts of a silane coupling agent and 0.3 parts of sodium dodecyl sulfate were weighed and added thereto. The mixture was stirred at a speed of 500 r / min for 1 hour. The mixture was washed alternately with deionized water and ethanol three times each to obtain modified diatomaceous earth.

[0064] This embodiment also provides a method for preparing an environmentally friendly fluorine- and heavy metal-containing water treatment agent, comprising the following steps:

[0065] Step 1. Weigh 10 parts of calcium carbide waste residue and sieve it under a 100-mesh screen, then add 25 parts of acetic acid solution, wherein the concentration of acetic acid solution is 0.25mol / L, ultrasonically treated at a power of 40kHz for 20min, and then centrifuged at a speed of 8000r / min for 10min to obtain a waste residue activation product;

[0066] Step 2. Weigh 6.5 parts of the clay modifier and 8 parts of the gel base material and add 15 parts of an ethanol solution, wherein the ethanol solution is a mixed solution of ethanol and water in a mass percentage of 70:30, and stir at a speed of 500 r / min for 40 min to obtain a paste;

[0067] Step 3. Weigh 1.5 parts of PVP and 0.2 parts of polyoxymethylene fiber and add them to 10 parts of deionized water, ultrasonicate at a power of 40kHz for 20 minutes, and then stir at a speed of 500r / min for 30 minutes to obtain a pre-reaction liquid. Add the waste residue activation obtained in step 1 to the pre-reaction liquid and heat it at a temperature of 60°C for 2 hours. Continue to add 1 part of polyacrylamide and the paste obtained in step 2, ultrasonicate at a power of 40kHz for 15 minutes, and then stir at a speed of 500r / min for 30 minutes. Dry it at a temperature of 80°C for 24 hours and crush it into particles with a particle size of 2 mm to obtain an environmentally friendly fluorine-containing and heavy metal water treatment agent.

[0068] Example 3: An environmentally friendly fluorine- and heavy metal-containing water treatment agent comprises the following raw materials in parts by weight: 12 parts of calcium carbide waste residue, 7.5 parts of clay modification, 8 parts of gel-based material, 2 parts of PVP, 1.5 parts of polyacrylamide and 0.3 parts of polyoxymethylene fiber.

[0069] The preparation method of the clay modified material comprises the following steps:

[0070] A. Weigh 8 parts of clay and sieve them through a 200-mesh sieve, 1 part of citric acid, and 0.8 parts of straw powder and sieve them through a 200-mesh sieve. Then, ball mill the above materials at a speed of 200 r / min for 30 minutes to obtain a calcined precursor.

[0071] B. calcining the precursor obtained in step A at 450° C. for 2.5 h at a heating rate of 10° C. / min, introducing argon gas at a flow rate of 300 mL / min during the calcination process, and then naturally cooling to room temperature to obtain calcined product I;

[0072] C. Weigh 3 parts of Fe3O4 and add them to the calcined product I obtained in step B. Ball milling is performed for 30 min using a ball mill at a rotation speed of 200 r / min. Then, a secondary calcination is performed at a temperature of 800°C for 3 h. The heating rate of the secondary calcination process is 5°C / min. Argon gas is introduced at a flow rate of 300 mL / min during the secondary calcination process. The mixture is then naturally cooled to room temperature and washed alternately with deionized water and ethanol three times each to obtain a clay modified product.

[0073] The preparation method of the gel-based substrate comprises the following steps:

[0074] α weighed 7 parts of chitosan was added to 15 parts of a 0.1mol / L acetic acid solution, stirred at a speed of 500r / min for 30min to obtain acetic acid activation;

[0075] β. Weigh 2.5 modified diatomaceous earth and add the acetic acid activated product obtained in step α, stir at a speed of 500r / min for 30min, then continue to weigh 1.2 parts of ethylene glycol and 3 parts of ethanol and add them, let stand for 4h in a water bath at 50 ° C, and cool naturally to room temperature to obtain a gel precursor;

[0076] γ. The gel precursor obtained in step β is placed in a low temperature condition of -5°C for curing for 24 hours, and then crushed into particles with a particle size of 1.5 mm, and dried at a temperature of 65°C for 48 hours to obtain a gel-based material.

[0077] The preparation method of modified diatomaceous earth comprises the following steps:

[0078] S1. Weigh 25 parts of diatomaceous earth and sieve it through a 200-mesh sieve. Then add it to 30 parts of deionized water and stir it at 500 r / min for 30 minutes. Then, add 2 parts of hydrogen peroxide. Heat it in a water bath at 40°C for 2 hours while stirring it at 500 r / min. Then, centrifuge it at 8000 r / min for 10 minutes to obtain oxidized diatomaceous earth.

[0079] S2. The oxidized diatomaceous earth obtained in step S1 was added to 20 parts of ethanol and stirred at a speed of 500 r / min for 20 minutes. 5 parts of a silane coupling agent and 0.3 parts of sodium dodecyl sulfate were weighed and added thereto. The mixture was stirred at a speed of 500 r / min for 1 hour. The mixture was washed alternately with deionized water and ethanol three times each to obtain modified diatomaceous earth.

[0080] This embodiment also provides a method for preparing an environmentally friendly fluorine- and heavy metal-containing water treatment agent, comprising the following steps:

[0081] Step 1. Weigh 12 parts of calcium carbide waste residue and sieve it under a 100-mesh screen, then add 25 parts of acetic acid solution, wherein the concentration of acetic acid solution is 0.25mol / L, ultrasonically treated at a power of 40kHz for 20min, and then centrifuged at a speed of 8000r / min for 10min to obtain a waste residue activation product;

[0082] Step 2. Weigh 7.5 parts of the clay modifier and 8 parts of the gel base material and add 15 parts of an ethanol solution, wherein the ethanol solution is a mixed solution of ethanol and water in a mass percentage of 70:30, and stir at a speed of 500 r / min for 40 min to obtain a paste;

[0083] Step 3. Weigh 2 parts of PVP and 0.3 parts of polyoxymethylene fiber and add them to 10 parts of deionized water, ultrasonicate at a power of 40kHz for 20 minutes, and then stir at a speed of 500r / min for 30 minutes to obtain a pre-reaction liquid. Add the activated waste residue obtained in step 1 to the pre-reaction liquid and heat it at a temperature of 60°C for 2 hours. Continue to add 1.5 parts of polyacrylamide and the paste obtained in step 2, ultrasonicate at a power of 40kHz for 15 minutes, and then stir at a speed of 500r / min for 30 minutes. Dry it at a temperature of 80°C for 24 hours and crush it into particles with a particle size of 2 mm to obtain an environmentally friendly fluorine-containing and heavy metal water treatment agent.

[0084] Comparative Example:

[0085] The difference between Comparative Example 1 and Example 2 is that no clay modifier is added, and the rest of the process is the same as Example 2;

[0086] The difference between Comparative Example 2 and Example 2 is that no gel base was added, and the rest of the components were the same as Example 2;

[0087] The difference between Comparative Example 3 and Example 2 is that the clay is not modified, and the rest is the same as Example 2;

[0088] The difference between Comparative Example 4 and Example 2 is that no calcium carbide waste slag is added, and the rest is the same as Example 2.

[0089] In order to study the performance of the prepared environmentally friendly fluorine-containing and heavy metal water treatment agent, the unmodified clay was first subjected to SEM testing. Figure 2 As shown in the figure, it can be seen that the overall particles of the clay are relatively uniform, and there are no large lumps of material. Then, TEM tests were further performed on the clay after adding straw powder and calcining with citric acid. Figure 3 As shown in the figure, it can be seen that there are certain pores in the clay, indicating that the addition of straw powder and citric acid is beneficial to provide more active sites. Further relevant tests were conducted on the EPR of clay before calcination and after adding straw powder and citric acid to the clay. Figure 4 As shown in the figure, it can be seen that there is a certain peak in the magnetic field intensity after calcination, indicating that there are certain defects after calcination, which provide more active sites for the adsorption of ions. Then, the environmentally friendly fluorine-containing and heavy metal water treatment agents prepared in the examples and comparative examples are used for F - The removal of this application is to simulate F - Wastewater was treated by preparing a 30 mg / L NaF solution. 100 mL or more of NaF solution was measured and 20 mg of an environmentally friendly fluorine-containing and heavy metal water treatment agent was added thereto. The solution was stirred at 300 r / min for 30 s. 5 mL was taken each time according to the adsorption time and 0.01 g of citric acid was added thereto. The alizarin zirconium sulfonate colorimetric method was used to analyze the NaF solution. - Conduct the measurement, Figure 5 F in water after adsorption - The test results show that after 20 minutes of adsorption, the environmentally friendly fluorine-containing and heavy metal water treatment agent prepared in the embodiment shows high adsorption. - The adsorption of fluorine-containing and heavy metal-containing water treatment agents was much higher than that of the control group, and the adsorption performance of the environmentally friendly fluorine-containing and heavy metal-containing water treatment agents under heavy metal environment conditions was further tested. The concentration of cadmium (Cd 2+ ), lead (Pb 2+ ) and mercury (Hg 2+) heavy metal ion solution, mixed according to 1:1:1, then measured 100mL of the mixed solution, added 30mg of environmentally friendly fluorine-containing and heavy metal water treatment agent, and tested the adsorption performance for 20min. The results are as follows Figure 6 As shown, in the heavy metal mixed solution to which the environmentally friendly fluorine-containing and heavy metal water treatment agent prepared in the embodiment is added, the detected concentration of ions is almost zero, showing a good adsorption effect on heavy metals, and the adsorption performance is higher than that of the comparative example, indicating that the environmentally friendly fluorine-containing and heavy metal water treatment agent prepared in the embodiment has better performance.

[0090] Obviously, the above comparative examples and embodiments are only a part of the comparative examples and embodiments of the present invention, and they and the comparative examples and embodiments based on such references are all within the scope of protection of this invention.

[0091] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

[0092] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. An environmentally friendly fluorine-containing and heavy metal water treatment agent, characterized in that: The preparation method comprises the following raw materials in parts by weight: 8-12 parts of calcium carbide waste residue, 5.5-7.5 parts of clay modification, 8 parts of gel-based material, 1-2 parts of PVP, 0.5-1.5 parts of polyacrylamide and 0.1-0.3 parts of polyoxymethylene fiber; The clay modification comprises the following raw materials in a mass ratio: clay, citric acid, Fe3O4, straw powder = 6-8:0.5-1:1-3:0.8; The gel-based substrate comprises raw materials in the following mass ratios: chitosan, modified diatomaceous earth, ethylene glycol, and ethanol = 4-7:2.5:1.2:1-3; the modified diatomaceous earth comprises raw materials in the following mass ratios: diatomaceous earth, hydrogen peroxide, silane coupling agent, and sodium dodecyl sulfate = 15-25:1-2:3.5-5:0.3; The modified diatomaceous earth is prepared by the following method: S1. Weigh diatomaceous earth, sieve it, add it to water, stir it, continue to add hydrogen peroxide, heat it and stir it, and centrifuge it to obtain oxidized diatomaceous earth; S2. The oxidized diatomaceous earth was added to ethanol, stirred, and a silane coupling agent and sodium dodecyl sulfate were added, stirred, and washed to obtain modified diatomaceous earth; The preparation method of the clay modification comprises the following steps: A. Weigh clay, citric acid, and straw powder, and ball-mill to obtain a calcined precursor; B. calcining the calcined precursor and cooling it to obtain a calcined product I; C. Fe3O4 is added to the calcined product I, ball milled, calcined twice, cooled, and washed to obtain a clay-modified product.

2. An environmentally friendly fluorine-containing and heavy metal water treatment agent according to claim 1, characterized in that: The temperature of the calcination treatment in step B is 450° C., and the heating rate of the calcination treatment is 10° C. / min. The temperature of the secondary calcination treatment in step C is 800° C., and the heating rate of the secondary calcination treatment is 5° C. / min.

3. The environmentally friendly fluorine-containing and heavy metal water treatment agent according to claim 1, characterized in that: The preparation method of the gel-based substrate comprises the following steps: α. Add chitosan to acetic acid and stir to obtain acetic acid activated product; β. Said modified diatomaceous earth was added to the acetic acid activated material, stirred, said ethylene glycol and ethanol were added, and allowed to stand to obtain a gel precursor; γ. The gel precursor is solidified at low temperature, crushed, and dried to obtain a gel-based material.

4. The environmentally friendly fluorine-containing and heavy metal water treatment agent according to claim 3, characterized in that: The acetic acid concentration in step α is 0.1 mol / L, the low-temperature curing temperature in step γ is -5°C, and the crushed particle size is 1-2 μm.

5. A method for preparing an environmentally friendly fluorine-containing and heavy metal water treatment agent according to any one of claims 1 to 4, characterized in that: The steps include: Step 1. Add the calcium carbide waste residue to acetic acid, ultrasonicate, and centrifuge to obtain an activated waste residue; Step 2. Weigh the clay modifier and the gel base and add them to the ethanol solution, stirring to obtain a paste; Step 3. Weigh PVP and polyoxymethylene fiber and add them into water, ultrasonicate and stir to obtain pre-reaction liquid, add the waste residue activation product into the pre-reaction liquid, heat it, continue to add polyacrylamide and paste, ultrasonicate and stir, dry and crush to obtain an environmentally friendly fluorine-containing and heavy metal water treatment agent.

6. The method for preparing an environmentally friendly fluorine-containing and heavy metal water treatment agent according to claim 5, characterized in that: The acetic acid concentration in step 1 is 0.25 mol / L, and the ethanol solution in step 2 is a mixed solution of ethanol and water prepared in a mass percentage of 70:30.

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