A wastewater decolorizing agent and preparation method thereof

Abstract

This case involves a wastewater decolorizer and its preparation method. First, natural attapulgite is pretreated with acid and alkali; then, tetraethyl orthosilicate and aluminum nitrate are added, and silicon dioxide and aluminum oxide are loaded on its surface by hydrolysis and impregnation; silane coupling agent KH570 is added to obtain modified attapulgite; acrylamide is reacted with dicyandiamide and formaldehyde to obtain a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond; and the dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond is polymerized in situ on the surface of the modified attapulgite. The present invention provides a decolorizer for industrial wastewater, which has high stability and can be used in combination with commercially available flocculants to effectively remove COD from water bodies. At the same time, at a relatively low addition amount, it can quickly decolorize industrial wastewater, thereby improving water treatment efficiency and reducing costs.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment agent preparation, in particular to a wastewater decolorizing agent and a preparation method thereof. Background Art

[0002] Water is the source of life. Water treatment is of great significance to the development of industrial production, the improvement of product quality, and the maintenance of ecological balance. There are many types of water treatment agents, including flocculants, sedimentation agents, corrosion inhibitors, bactericides, deodorants, decolorants, cleaning agents, etc. In practical applications, it is often necessary to use a composite formula of water treatment agents for wastewater generated by different industries. Therefore, it is necessary to pay attention to the antagonistic effects caused by inappropriate compounding between the components, and to make full use of the synergistic effect to increase efficiency. Among them, the decolorization of wastewater has always been one of the hot issues in the field of water treatment. The commonly used decolorizers in the industry are activated carbon, but the activated carbon has a slow absorption rate and a large consumption; organic decolorizers such as dicyandiamide-formaldehyde condensation products have a high decolorization rate, but the price of using dicyandiamide alone is relatively expensive, which increases the decolorization cost, and dicyandiamide formaldehyde condensation products usually have a low molecular weight and are not easy to store. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention uses modified attapulgite as a carrier, loads silica on its surface, and simultaneously utilizes in-situ polymerization to form a macromolecular polymer chain of dicyandiamide formaldehyde on its surface. The macromolecular polymer chain has a large specific surface area of ​​attapulgite and excellent adsorption performance, and the long polymer chain is beneficial to improving the decolorization rate, so the macromolecular polymer chain can be used as an auxiliary additive for sewage treatment.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for preparing a wastewater decolorizing agent comprises the following steps:

[0006] 1) Performing acid-base pretreatment on natural attapulgite;

[0007] 2) Add template F127 and ethanol to a container and stir to dissolve, then add tetraethyl orthosilicate and stir for 2 hours, then add aluminum nitrate solution and stir to mix evenly, immerse the pretreated attapulgite in the mixed solution for 4 to 6 hours, add 10 wt% ammonia water under stirring, adjust the pH to 9 to 10, heat to 70°C and continue stirring for 6 to 8 hours, cool and filter, and calcine the obtained solid at 400 to 600°C for 2 hours;

[0008] 3) ultrasonically dispersing the solid obtained in step 2) in tetrahydrofuran solvent, heating to 50° C., adding KH570, condensing and reflux overnight, filtering, washing with anhydrous ethanol and deionized water, and drying to obtain modified attapulgite;

[0009] 4) acrylamide reacts with dicyandiamide and formaldehyde to obtain a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond;

[0010] 5) The modified attapulgite is uniformly dispersed in tetrahydrofuran and nitrogen is passed through for protection, an initiator is added and stirred evenly, the temperature is raised to 70° C., a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond is dissolved in a tetrahydrofuran solvent, and then added dropwise to the attapulgite dispersion. After the addition is completed, the nitrogen atmosphere is maintained and stirred for 5 to 10 hours. After cooling, the product is washed with anhydrous ethanol, dried, and crushed to obtain.

[0011] Furthermore, the specific process of step 1) is as follows:

[0012] Soak the attapulgite in a 1M sodium hydroxide solution for 2 hours, filter, wash and calcine, disperse in deionized water after cooling, add sodium chloride to adjust the pH to neutral, filter and dry; soak the dried attapulgite in a 10% hydrochloric acid solution, heat in a water bath for 1 hour, cool and filter, dry, crush and set aside.

[0013] Furthermore, the solid-liquid ratio of the attapulgite in the sodium hydroxide solution and the hydrochloric acid solution is 1:2, and the calcination temperature is 450°C.

[0014] Furthermore, in the step 2), the mass ratio of template F127, tetraethyl orthosilicate and attapulgite is 1:1.2 to 3:5; the mass fraction of the aluminum nitrate solution is 10%, and the mass ratio of aluminum nitrate to attapulgite is 1:1 to 2.

[0015] Furthermore, the specific process of step 4) is as follows:

[0016] According to the molar ratio of acrylamide, dicyandiamide and formaldehyde of 1:2:2, the raw materials are weighed and placed in a reaction bottle, 30wt% hydrochloric acid solution is slowly added dropwise, the temperature is raised to 70°C and reacted for 5-10 minutes, then the heat source is removed, the reaction is continued for 2-3 hours, and rotary evaporation is performed to obtain the product; wherein the mass of the hydrochloric acid solution is 20% of the total mass of the three monomers.

[0017] Furthermore, in the step 5), the mass ratio of the modified attapulgite to the dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds is 1:0.5-1.

[0018] The present invention further provides a wastewater decolorizing agent prepared by the preparation method as described above.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention provides a wastewater decolorizer with high stability, which can be used in combination with commercially available flocculants to effectively remove COD from water bodies, and at the same time, can quickly decolorize industrial wastewater at a relatively low addition amount, thereby improving water treatment efficiency and reducing costs. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Example

[0023] A method for preparing a wastewater decolorizing agent comprises the following steps:

[0024] 1) Acid-base pretreatment of natural attapulgite:

[0025] Soak the attapulgite in a 1M sodium hydroxide solution for 2 hours, filter, wash and calcine, disperse in deionized water after cooling, add sodium chloride to adjust the pH to neutral, filter and dry; soak the dried attapulgite in a 10% hydrochloric acid solution, heat in a water bath for 1 hour, cool and filter, dry, crush and set aside.

[0026] 2) Add template F127 and ethanol to a container and stir to dissolve them, then add tetraethyl orthosilicate and stir for 2 hours, then add aluminum nitrate solution and stir to mix evenly, immerse the pretreated attapulgite in the mixed solution for 4 to 6 hours, add 10wt% ammonia water while stirring, adjust the pH to 9 to 10, heat to 70°C and continue stirring for 6 to 8 hours, cool and filter, and calcine the obtained solid at 400 to 600°C for 2 hours; the mass ratio of template F127, tetraethyl orthosilicate, and attapulgite is 1:1.2 to 3:5; the mass fraction of the aluminum nitrate solution is 10%, and the mass ratio of aluminum nitrate to attapulgite is 1:1 to 2.

[0027] 3) ultrasonically dispersing the solid obtained in step 2) in tetrahydrofuran solvent, heating to 50° C., adding KH570, condensing and reflux overnight, filtering, washing with anhydrous ethanol and deionized water, and drying to obtain modified attapulgite;

[0028] 4) Preparation of dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds:

[0029] According to the molar ratio of acrylamide, dicyandiamide and formaldehyde of 1:2:2, the raw materials are weighed and placed in a reaction bottle, 30wt% hydrochloric acid solution is slowly added dropwise, the temperature is raised to 70°C and reacted for 5-10 minutes, then the heat source is removed, the reaction is continued for 2-3 hours, and rotary evaporation is performed to obtain the product; wherein the mass of the hydrochloric acid solution is 20% of the total mass of the three monomers.

[0030] 5) The modified attapulgite is uniformly dispersed in tetrahydrofuran and nitrogen is passed through for protection, an initiator is added and stirred evenly, the temperature is raised to 70° C., a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond is dissolved in a tetrahydrofuran solvent, and then added dropwise to the attapulgite dispersion. After the addition is completed, the nitrogen atmosphere is maintained and stirred for 5 to 10 hours. After cooling, the product is washed with anhydrous ethanol, dried, and crushed to obtain.

[0031] The present invention takes into account that dicyandiamide is expensive, and the molecular weight of the condensation polymer is low and the storage stability is poor. Therefore, the dicyandiamide formaldehyde condensation polymer is pre-made into a reactive polymer, and in-situ polymerization is carried out on the surface of attapulgite, while reducing the amount of dicyandiamide, the polymer molecular weight is increased. In this case, attapulgite is selected as the matrix material. As a natural mineral with a large specific surface area, it has a certain adsorption capacity, and natural attapulgite contains a large amount of impurities. Therefore, in this case, purified attapulgite is first obtained by acid-base treatment, which increases the specific surface area and enriches the surface active groups and bonding points. After that, ethyl orthosilicate and aluminum nitrate are added, and silicon dioxide and aluminum oxide are loaded on its surface by hydrolysis and impregnation. The added template further increases the pore size during the calcination process to avoid the attapulgite mesopores being blocked by silicon dioxide and aluminum oxide nanoparticles. The treated attapulgite is then connected by an organic-inorganic bridge with KH570, and then in situ polymerized with a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond. In this case, the dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond is obtained by first reacting dicyandiamide with formaldehyde to obtain hydroxymethyl dicyandiamide, and then reacting with the amino group of acrylamide under acidic conditions, and dehydration and polycondensation occur between the hydroxymethyl groups at the same time, thereby obtaining a low molecular weight prepolymer containing terminal propylene groups, and then free radical polymerization is performed on the surface of the attapulgite to form a macromolecular brush-like polymer chain, which increases the molecular weight and can achieve a significant decolorization effect at a low dosage. In addition, polyacrylamide is also a commonly used water treatment coagulant. The introduction of acrylamide is conducive to improving the flocculation ability, and the silica and alumina pre-loaded on the surface of the attapulgite can not only further improve the adsorption capacity, but also help to capture the free formaldehyde in the dicyandiamide formal polymer, reducing the harm to the environment. The organically modified attapulgite can also become a carrier for the immobilization of microorganisms. In the water treatment process, it can play a synergistic role in combination with biological methods to more efficiently remove water pollutants and improve the decolorization rate.

[0032] Embodiment 1:

[0033] A method for preparing a wastewater decolorizing agent comprises the following steps:

[0034] 1) Acid-base pretreatment of natural attapulgite:

[0035] Soak the attapulgite in a 1M sodium hydroxide solution for 2 hours with a solid-liquid ratio of 1:2, filter and wash, dry and calcine at 450°C, disperse in deionized water after cooling, add sodium chloride to adjust the pH to neutral, filter and dry; soak the dried attapulgite in a 10% hydrochloric acid solution with a solid-liquid ratio of 1:2, heat in a water bath for 1 hour, cool and filter, dry, crush and set aside.

[0036] 2) Add 2 g of template F127 and 10 mL of ethanol to a container and stir to dissolve, then add 2.4 g of tetraethyl orthosilicate and stir for 2 h, then add 100 mL of 10 wt% aluminum nitrate solution and stir to mix evenly, soak 10 g of pretreated attapulgite in the mixed solution for 4 to 6 h, add 10 wt% ammonia water while stirring, adjust the pH to 9 to 10, heat to 70 ° C and continue stirring for 6 to 8 h, cool and filter, and calcine the obtained solid at 500 ° C for 2 h.

[0037] 3) The solid obtained in step 2) was ultrasonically dispersed in 100 mL of tetrahydrofuran solvent, the temperature was raised to 50° C., 2 g of KH570 was added, condensed and refluxed overnight, filtered, washed with anhydrous ethanol and deionized water, and dried to obtain modified attapulgite.

[0038] 4) Preparation of dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds:

[0039] According to the molar ratio of acrylamide, dicyandiamide and formaldehyde of 1:2:2, the raw materials are weighed and placed in a reaction bottle, 30wt% hydrochloric acid solution is slowly added dropwise, the temperature is raised to 70°C and reacted for 5-10 minutes, then the heat source is removed, the reaction is continued for 2-3 hours, and rotary evaporation is performed to obtain the product; wherein the mass of the hydrochloric acid solution is 20% of the total mass of the three monomers.

[0040] 5) 5 g of modified attapulgite is evenly dispersed in tetrahydrofuran and nitrogen is passed through it for protection. An initiator is added and stirred evenly. The temperature is raised to 70° C. 0.5 g of a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond is dissolved in a tetrahydrofuran solvent and then added dropwise to the attapulgite dispersion. After the addition is completed, the nitrogen atmosphere is maintained and stirred for 6 hours. After cooling, the product is washed with anhydrous ethanol, dried, and crushed to obtain the product.

[0041] Embodiment 2:

[0042] A method for preparing a wastewater decolorizing agent comprises the following steps:

[0043] 1) Acid-base pretreatment of natural attapulgite:

[0044] Soak the attapulgite in a 1M sodium hydroxide solution for 2 hours with a solid-liquid ratio of 1:2, filter and wash, dry and calcine at 450°C, disperse in deionized water after cooling, add sodium chloride to adjust the pH to neutral, filter and dry; soak the dried attapulgite in a 10% hydrochloric acid solution with a solid-liquid ratio of 1:2, heat in a water bath for 1 hour, cool and filter, dry, crush and set aside.

[0045] 2) Add 2 g of template F127 and 10 mL of ethanol to a container and stir to dissolve, then add 4 g of tetraethyl orthosilicate and stir for 2 h, then add 100 mL of 10 wt% aluminum nitrate solution and stir to mix evenly, soak 10 g of pretreated attapulgite in the mixed solution for 4 to 6 h, add 10 wt% ammonia water while stirring, adjust the pH to 9 to 10, heat to 70 ° C and continue stirring for 6 to 8 h, cool and filter, and calcine the obtained solid at 500 ° C for 2 h.

[0046] 3) The solid obtained in step 2) was ultrasonically dispersed in 100 mL of tetrahydrofuran solvent, the temperature was raised to 50° C., 2 g of KH570 was added, condensed and refluxed overnight, filtered, washed with anhydrous ethanol and deionized water, and dried to obtain modified attapulgite.

[0047] 4) Preparation of dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds:

[0048] According to the molar ratio of acrylamide, dicyandiamide and formaldehyde of 1:2:2, the raw materials are weighed and placed in a reaction bottle, 30wt% hydrochloric acid solution is slowly added dropwise, the temperature is raised to 70°C and reacted for 5-10 minutes, then the heat source is removed, the reaction is continued for 2-3 hours, and rotary evaporation is performed to obtain the product; wherein the mass of the hydrochloric acid solution is 20% of the total mass of the three monomers.

[0049] 5) 5 g of modified attapulgite is evenly dispersed in tetrahydrofuran and nitrogen is passed through it for protection. An initiator is added and stirred evenly. The temperature is raised to 70° C. 0.7 g of a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond is dissolved in a tetrahydrofuran solvent and then added dropwise to the attapulgite dispersion. After the addition is completed, the nitrogen atmosphere is maintained and stirred for 6 hours. After cooling, the product is washed with anhydrous ethanol, dried, and crushed to obtain the product.

[0050] Embodiment 3:

[0051] A method for preparing a wastewater decolorizing agent comprises the following steps:

[0052] 1) Acid-base pretreatment of natural attapulgite:

[0053] Soak the attapulgite in a 1M sodium hydroxide solution for 2 hours with a solid-liquid ratio of 1:2, filter and wash, dry and calcine at 450°C, disperse in deionized water after cooling, add sodium chloride to adjust the pH to neutral, filter and dry; soak the dried attapulgite in a 10% hydrochloric acid solution with a solid-liquid ratio of 1:2, heat in a water bath for 1 hour, cool and filter, dry, crush and set aside.

[0054] 2) Add 2 g of template F127 and 10 mL of ethanol to a container and stir to dissolve, then add 6 g of tetraethyl orthosilicate and stir for 2 h, then add 100 mL of 10 wt% aluminum nitrate solution and stir to mix evenly, soak 10 g of pretreated attapulgite in the mixed solution for 4 to 6 h, add 10 wt% ammonia water while stirring, adjust the pH to 9 to 10, heat to 70 ° C and continue stirring for 6 to 8 h, cool and filter, and calcine the obtained solid at 500 ° C for 2 h.

[0055] 3) The solid obtained in step 2) was ultrasonically dispersed in 100 mL of tetrahydrofuran solvent, the temperature was raised to 50° C., 2 g of KH570 was added, condensed and refluxed overnight, filtered, washed with anhydrous ethanol and deionized water, and dried to obtain modified attapulgite.

[0056] 4) Preparation of dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds:

[0057] According to the molar ratio of acrylamide, dicyandiamide and formaldehyde of 1:2:2, the raw materials are weighed and placed in a reaction bottle, 30wt% hydrochloric acid solution is slowly added dropwise, the temperature is raised to 70°C and reacted for 5-10 minutes, then the heat source is removed, the reaction is continued for 2-3 hours, and rotary evaporation is performed to obtain the product; wherein the mass of the hydrochloric acid solution is 20% of the total mass of the three monomers.

[0058] 5) 5 g of modified attapulgite is evenly dispersed in tetrahydrofuran and nitrogen is passed through it for protection. An initiator is added and stirred evenly. The temperature is raised to 70° C. 0.7 g of a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond is dissolved in a tetrahydrofuran solvent and then added dropwise to the attapulgite dispersion. After the addition is completed, the nitrogen atmosphere is maintained and stirred for 6 hours. After cooling, the product is washed with anhydrous ethanol, dried, and crushed to obtain the product.

[0059] Embodiment 4:

[0060] A method for preparing a wastewater decolorizing agent comprises the following steps:

[0061] 1) Acid-base pretreatment of natural attapulgite:

[0062] Soak the attapulgite in a 1M sodium hydroxide solution for 2 hours with a solid-liquid ratio of 1:2, filter and wash, dry and calcine at 450°C, disperse in deionized water after cooling, add sodium chloride to adjust the pH to neutral, filter and dry; soak the dried attapulgite in a 10% hydrochloric acid solution with a solid-liquid ratio of 1:2, heat in a water bath for 1 hour, cool and filter, dry, crush and set aside.

[0063] 2) ultrasonically dispersing the solid obtained in step 1) in 100 mL of tetrahydrofuran solvent, heating to 50° C., adding 2 g of KH570, condensing and refluxed overnight, filtering, washing with anhydrous ethanol and deionized water, and drying to obtain modified attapulgite;

[0064] 3) Preparation of dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds:

[0065] According to the molar ratio of acrylamide, dicyandiamide and formaldehyde of 1:2:2, the raw materials are weighed and placed in a reaction bottle, 30wt% hydrochloric acid solution is slowly added dropwise, the temperature is raised to 70°C and reacted for 5-10 minutes, then the heat source is removed, the reaction is continued for 2-3 hours, and rotary evaporation is performed to obtain the product; wherein the mass of the hydrochloric acid solution is 20% of the total mass of the three monomers.

[0066] 4) 5 g of modified attapulgite is evenly dispersed in tetrahydrofuran and nitrogen is passed through it for protection. An initiator is added and stirred evenly. The temperature is raised to 70° C. 0.5 g of a dicyandiamide formaldehyde prepolymer containing a carbon-carbon double bond is dissolved in a tetrahydrofuran solvent and then added dropwise to the attapulgite dispersion. After the addition is completed, the nitrogen atmosphere is maintained and stirred for 6 hours. After cooling, the product is washed with anhydrous ethanol, dried, and crushed to obtain the product.

[0067] Embodiment 5:

[0068] A method for preparing a wastewater decolorizing agent comprises the following steps:

[0069] 1) Acid-base pretreatment of natural attapulgite:

[0070] Soak the attapulgite in a 1M sodium hydroxide solution for 2 hours with a solid-liquid ratio of 1:2, filter and wash, dry and calcine at 450°C, disperse in deionized water after cooling, add sodium chloride to adjust the pH to neutral, filter and dry; soak the dried attapulgite in a 10% hydrochloric acid solution with a solid-liquid ratio of 1:2, heat in a water bath for 1 hour, cool and filter, dry, crush and set aside.

[0071] 2) Add 2 g of template F127 and 10 mL of ethanol to a container and stir to dissolve, then add 2.4 g of tetraethyl orthosilicate and stir for 2 h, then add 100 mL of 10 wt% aluminum nitrate solution and stir to mix evenly, soak 10 g of pretreated attapulgite in the mixed solution for 4 to 6 h, add 10 wt% ammonia water while stirring, adjust the pH to 9 to 10, heat to 70 ° C and continue stirring for 6 to 8 h, cool and filter, and calcine the obtained solid at 500 ° C for 2 h.

[0072] 3) The solid obtained in step 2) was ultrasonically dispersed in 100 mL of tetrahydrofuran solvent, the temperature was raised to 50° C., 2 g of KH560 was added, condensed and refluxed overnight, filtered, washed with anhydrous ethanol and deionized water, and dried to obtain modified attapulgite.

[0073] 4) Disperse 5 g of modified attapulgite in an appropriate amount of deionized water, add 0.05 mol of dicyandiamide, 0.14 mol of formaldehyde and 0.02 mol of ammonium chloride, heat in a water bath at 70°C for 2 hours, filter and dry to obtain the product.

[0074] Take 1L of industrial wastewater (pH=7.9, COD=965mg / L, chromaticity 580), add 100mg of the above-prepared decolorizing agent, shake for 30min, let it stand and take samples to test the COD removal rate and decolorization rate, and record them in Table 1.

[0075] Table 1

[0076] Example 1 Example 2 Example 3 Example 4 Example 5 COD removal rate % 89.5 90.2 87.3 76.4 82.3 Decolorization rate % 97.8 99.1 98.8 90.2 78.5

[0077] It can be seen from the table above that Example 2 has the best comprehensive effect. In the reaction process of step 2), the higher the content of aluminum oxide and silicon oxide is, the better it is. When the content increases, it is easy to cause blockage, and the COD removal rate will decrease. Comparing Example 4, it can also be found that the presence of step 2) can effectively improve the COD removal rate. In Example 5, since attapulgite is directly involved in the preparation process of dicyandiamide formaldehyde condensation product, the polymer chain formed is short and the molecular weight is low, and the decolorization effect on industrial wastewater is significantly reduced. In this application, a relatively small amount of decolorizing agent can achieve a higher decolorization effect, and the COD removal rate has reached about 90%. In practical applications, it can also be matched with a small amount of commercially available flocculants to more efficiently treat wastewater.

[0078] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A method for preparing a wastewater decolorizing agent, characterized in that: The steps include: 1) Acid-base pretreatment of natural attapulgite; 2) Add template F127 and ethanol to a container and stir to dissolve, then add tetraethyl orthosilicate and stir for 2 h, then add aluminum nitrate solution and stir to mix evenly, immerse the pretreated attapulgite in the mixed solution for 4-6 h, add 10 wt% ammonia water while stirring, adjust the pH to 9-10, heat to 70 °C and continue stirring for 6-8 h, cool and filter, and calcine the obtained solid at 400-600 °C for 2 h; 3) ultrasonically dispersing the solid obtained in step 2) in tetrahydrofuran solvent, heating to 50° C., adding KH570, condensing and reflux overnight, filtering, washing with anhydrous ethanol and deionized water, and drying to obtain modified attapulgite; 4) Acrylamide reacts with dicyandiamide and formaldehyde to obtain dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds; 5) Disperse the modified attapulgite evenly in tetrahydrofuran and pass nitrogen for protection, add the initiator and stir evenly, raise the temperature to 70°C, dissolve the dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds in tetrahydrofuran solvent, and then add it dropwise to the attapulgite dispersion. After the addition is completed, maintain the nitrogen atmosphere and stir the reaction for 5 to 10 hours. After cooling, wash the product with anhydrous ethanol, dry, and crush to obtain the product.

2. The method for preparing a wastewater decolorizing agent according to claim 1, characterized in that: The specific process of step 1) is as follows: Soak the attapulgite in a 1M sodium hydroxide solution for 2 hours, filter, wash and calcine, disperse in deionized water after cooling, add sodium chloride to adjust the pH to neutral, filter and dry; soak the dried attapulgite in a 10% hydrochloric acid solution, heat in a water bath for 1 hour, cool and filter, dry, crush and set aside.

3. The method for preparing a wastewater decolorizing agent according to claim 1, characterized in that: In the step 2), the mass ratio of template F127, tetraethyl orthosilicate and attapulgite is 1:1.2-3:5; the mass fraction of the aluminum nitrate solution is 10%, and the mass ratio of aluminum nitrate to attapulgite is 1:1-2.

4. The method for preparing a wastewater decolorizing agent according to claim 1, characterized in that: The specific process of step 4) is as follows: According to the molar ratio of acrylamide, dicyandiamide and formaldehyde of 1:2:2, the raw materials are weighed and placed in a reaction bottle, and 30wt% hydrochloric acid solution is slowly added dropwise, and the temperature is raised to 70°C for reaction for 5-10 minutes, and then the heat source is removed, and the reaction is continued for 2-3 hours, and concentrated by rotary evaporation to obtain; wherein, the mass of the hydrochloric acid solution is 20% of the total mass of the three monomers.

5. The method for preparing a wastewater decolorizing agent according to claim 1, characterized in that: In the step 5), the mass ratio of the modified attapulgite to the dicyandiamide formaldehyde prepolymer containing carbon-carbon double bonds is 1:0.5-1.

6. A wastewater decolorizing agent obtained by the preparation method according to any one of claims 1 to 5.