An acidic sewage treatment agent and a method for preparing the same

Abstract

The application relates to the technical field of sewage treatment, and discloses an acidic sewage treatment agent and a preparation method thereof. Chitosan, triazine group modified bentonite, cyclodextrin modified phenolic aldehyde resin and polyacrylamide are added into a stirrer, stirring is carried out, and the acidic sewage treatment agent is obtained after the stirring is completed. The cyclodextrin contained in the cyclodextrin modified phenolic aldehyde resin has a unique cavity structure. For heavy metal ions in sewage, the cyclodextrin can adsorb the heavy metal ions through the hydrophobic action in the cavity and the coordination action of the hydroxyl functional groups on the outside. The phenolic aldehyde resin contains a high content of phenolic hydroxyl groups and has strong hydrophilicity, and has a good adsorption effect on chromium ions and lead ions in wastewater. The triazine group and the bentonite can remove heavy metal ions. The quaternary ammonium salt can also remove heavy metal ions in sewage through complexation.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an acidic wastewater treatment agent and its preparation method. Background Technology

[0002] Acidic wastewater mainly originates from industries such as metallurgy, metal processing, petrochemicals, chemical fibers, and electroplating. This wastewater contains large amounts of heavy metal ions, which can harm human health if it flows into rivers. For example, patent CN104787821B discloses an industrial wastewater treatment agent. This agent has a fast reaction speed, does not corrode equipment, and is easy to use without altering the process flow or requiring additional equipment or materials. However, the metal ions it contains will remain in the water, still posing a risk to human health. Therefore, avoiding this phenomenon is key to solving the problem.

[0003] Chitosan is a natural alkaline polysaccharide with excellent biological functions and chemical modification reactivity, showing promising application prospects in wastewater treatment. This invention combines chitosan with triazine-modified bentonite, cyclodextrin-modified phenolic resin, and polyacrylamide to prepare an acidic wastewater treatment agent. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides an acidic wastewater treatment agent and its preparation method, which efficiently removes heavy metal ions from acidic wastewater.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution: an acidic wastewater treatment agent comprising the following weight components: 20-32 parts by weight of chitosan, 6-12 parts by weight of triazine-modified bentonite, 7-15 parts by weight of cyclodextrin-modified phenolic resin, and 6-10 parts by weight of polyacrylamide.

[0008] Preferably, the preparation method of the triazine-modified bentonite is as follows:

[0009] (1) Add 8-14g of γ-glycidyl etheroxypropyltrimethoxysilane modified bentonite to a sulfuric acid solution with a mass fraction of 2-3%, stir the reaction at 65-80℃, filter, wash and dry to obtain hydroxylated bentonite.

[0010] (2) Add deionized water, hydroxylated bentonite, and chloroacetyl chloride to the flask, stir evenly, continue to add pyridine catalyst, react at 40-55℃ for 7-10h, then continue to add 2,4,6-tris(dimethylamino)triazine to carry out quaternization reaction, react at 70-90℃ for 6-8h, filter after completion, wash with ethanol to obtain triazine-modified bentonite.

[0011] Preferably, the reaction time in step (1) is 14-18 hours.

[0012] Preferably, in step (2), the mass ratio of hydroxylated bentonite, chloroacetyl chloride, pyridine catalyst, and 2,4,6-tris(dimethylamino)triazine is 1:2.1-2.6:0.01-0.22:0.8-1.2.

[0013] Preferably, the method for preparing the cyclodextrin-modified phenolic resin is as follows:

[0014] S1. Phenolic resin and epichlorohydrin are mixed evenly and reacted at 80-95℃ for 6-10h. Then, the mixture is concentrated under reduced pressure and washed to obtain epoxidized phenolic resin. The mass ratio of phenolic resin to epichlorohydrin is 6-10:12-15.

[0015] S2. Add hydroxyl bentonite to 1,4-dioxane, stir and disperse, then add epoxidized phenolic resin and boron trifluoride diethyl ether, react at 75-90℃ for 7-12h, filter, wash and dry to obtain bentonite-modified phenolic resin; wherein the mass ratio of hydroxyl bentonite, epoxidized phenolic resin and boron trifluoride diethyl ether is 4-8:5-8:0.01-0.03;

[0016] S3. Dissolve hyponitrotriacetic acid and bentonite-modified phenolic resin in N,N-dimethylformamide solvent, then add 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, and reflux at 90-110℃ for 7-12h. After the reaction, precipitate, filter, and wash to obtain carboxyl hyperbranched phenolic resin.

[0017] S4. Add carboxyl hyperbranched phenolic resin to N,N-dimethylformamide, stir evenly, then add β-cyclodextrin and p-toluenesulfonic acid catalyst. After reaction, filter and wash to obtain cyclodextrin modified phenolic resin.

[0018] Preferably, the mass ratio of hyponitrotriacetic acid, bentonite-modified phenolic resin, 4-dimethylaminopyridine, and N,N-dicyclohexylcarbodiimide in S3 is 1:0.8-1.3:0.02-0.04:0.01-0.03.

[0019] Preferably, the mass ratio of carboxylated hyperbranched phenolic resin, β-cyclodextrin, and p-toluenesulfonic acid catalyst in S4 is 1:2.5-2.8:0.02-0.04.

[0020] Preferably, the preparation method of the acidic wastewater treatment agent is as follows: chitosan, triazine-modified bentonite, cyclodextrin-modified phenolic resin, and polyacrylamide are ultrasonically mixed: the ultrasonic frequency is set to 20kHz-50kHz, the ultrasonic power is 200-300W, and the ultrasonic treatment time is 15-25min, after which the acidic wastewater treatment agent is obtained.

[0021] (III) Beneficial Effects

[0022] This invention involves adding chitosan, triazine-modified bentonite, cyclodextrin-modified phenolic resin, and polyacrylamide to a stirrer, stirring, and then obtaining an acidic wastewater treatment agent.

[0023] γ-glycidoxypropyltrimethoxysilane-modified bentonite was hydrolyzed in sulfuric acid solution to obtain hydroxylated bentonite. The hydroxyl groups in the hydroxylated bentonite reacted with the acyl chloride in chloroacetyl chloride to generate ester groups, simultaneously introducing chlorine groups. Further, these chlorine groups reacted with the tertiary amine groups in 2,4,6-tris(dimethylamino)triazine to generate quaternary ammonium salts, introducing triazine groups, thus obtaining triazine-modified bentonite. Phenolic resin and epichlorohydrin were reacted to obtain epoxidized phenolic resin. The hydroxyl groups in the hydroxylated bentonite and the epoxy groups in the epoxidized phenolic resin underwent an addition reaction to generate hydroxyl groups, thus obtaining bentonite-modified phenolic resin. The carboxyl groups in hypozoxytriacetic acid and the hydroxyl groups in the bentonite-modified phenolic resin were esterified to obtain carboxyl hyperbranched phenolic resin. β-cyclodextrin was then added to cap the resin, yielding cyclodextrin-modified phenolic resin.

[0024] The cyclodextrin-modified phenolic resin contains cyclodextrin with a unique cavity structure. For heavy metal ions in wastewater, cyclodextrin can adsorb heavy metal ions through the hydrophobic interaction within its cavity and the coordination interaction of its hydroxyl functional groups on the outside. The phenolic resin itself has a high phenolic hydroxyl content and strong hydrophilicity, exhibiting good adsorption effects for chromium and lead ions in wastewater. The triazine group it contains is a six-membered heterocyclic structure with three nitrogen atoms. These nitrogen atoms, due to their strong electronegativity, can act as coordinating atoms to form stable complexes with metal ions. The bentonite has a large specific surface area and good adsorption capacity. The cations between the montmorillonite layers can effectively exchange with chromium and lead ions in wastewater, thereby removing heavy metal ions. The quaternary ammonium salt it contains can also remove heavy metal ions from wastewater through complexation. Furthermore, the cyclodextrin-modified phenolic resin contains a hyperbranched structure, and the end-capping with β-cyclodextrin increases its degree of substitution, enabling better adsorption of heavy metal ions. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] The raw materials used in the embodiments of this invention are as follows:

[0027] γ-glycidyl etheroxypropyltrimethoxysilane modified bentonite was prepared according to the literature "Adsorption performance of tetraethylenepentamine-grafted bentonite for Acid Red GR" (Chemical Industry and Engineering Progress, Vol. 40, No. 5, 2021):

[0028] Add 2g of bentonite to 100 mL of 7% hydrochloric acid solution, and reflux at 80℃ for acidification. Filter, wash with deionized water, and dry to obtain acid-modified bentonite. Disperse 2g of acid-modified bentonite in 150 mL of ethanol, add 8g of γ-glycidoxypropyltrimethoxysilane, and react under nitrogen atmosphere at 90℃ with stirring and reflux for 24 h. Filter, wash with ethanol, and dry to obtain γ-glycidoxypropyltrimethoxysilane-modified bentonite.

[0029] Example 1

[0030] (1) 8g of γ-glycidyl etheroxypropyltrimethoxysilane modified bentonite was added to a 2% sulfuric acid solution and stirred at 65°C for 14h. After the reaction was completed, the bentonite was filtered, washed and dried to obtain hydroxylated bentonite.

[0031] (2) Add 80 ml of deionized water, 1 g of hydroxylated bentonite, and 2.1 g of chloroacetyl chloride to the flask, stir well, and continue to add 0.01 g of pyridine catalyst. React at 40 °C for 7 h, and then add 0.8 g of 2,4,6-tris(dimethylamino)triazine to carry out quaternization reaction. React at 70 °C for 6 h. After the reaction is completed, filter and wash with ethanol to obtain triazine-modified bentonite.

[0032] (3) Mix 6g of phenolic resin and 12g of epichlorohydrin evenly, react at 80℃ for 6h, then concentrate under reduced pressure and wash to obtain epoxidized phenolic resin.

[0033] (4) Add 4g of hydroxy bentonite to 70ml of 1,4-dioxane, stir and disperse, then add 5g of epoxidized phenolic resin and 0.01g of boron trifluoride ether, react at 75℃ for 7h, filter after the reaction, wash and dry to obtain bentonite-modified phenolic resin.

[0034] (5) Dissolve 1g of hyponitrotriacetic acid and 0.8g of bentonite-modified phenolic resin in 100ml of N,N-dimethylformamide solvent, then add 0.02g of 4-dimethylaminopyridine and 0.01g of N,N-dicyclohexylcarbodiimide, reflux at 90℃ for 7h, precipitate, filter, and wash to obtain carboxyl hyperbranched phenolic resin;

[0035] (6) Add 1g of carboxylated hyperbranched phenolic resin to 85ml of N,N-dimethylformamide, stir evenly, then add 2.5g of β-cyclodextrin and 0.02g of p-toluenesulfonic acid catalyst. After reaction, filter and wash to obtain cyclodextrin modified phenolic resin.

[0036] (7) 20g of chitosan, 6g of triazine-modified bentonite, 7g of cyclodextrin-modified phenolic resin and 6g of polyacrylamide were ultrasonically mixed: the ultrasonic frequency was set to 20kHz, the ultrasonic power was 200W and the ultrasonic treatment time was 15min. After the treatment, an acidic wastewater treatment agent was obtained.

[0037] Example 2

[0038] (1) 14g of γ-glycidyl etheroxypropyltrimethoxysilane modified bentonite was added to a 3% sulfuric acid solution and stirred at 80°C for 18h. After the reaction was completed, the bentonite was filtered, washed and dried to obtain hydroxylated bentonite.

[0039] (2) Add 120 ml of deionized water, 2 g of hydroxylated bentonite, and 5.2 g of chloroacetyl chloride to the flask, stir well, and continue to add 0.44 g of pyridine catalyst. React at 55 °C for 10 h, and then add 2.4 g of 2,4,6-tris(dimethylamino)triazine to carry out quaternization reaction. React at 90 °C for 8 h. After the reaction is completed, filter and wash with ethanol to obtain triazine-modified bentonite.

[0040] (3) Mix 10g of phenolic resin and 15g of epichlorohydrin evenly, react at 95℃ for 10h, then concentrate under reduced pressure and wash to obtain epoxidized phenolic resin.

[0041] (4) Add 8g of hydroxy bentonite to 90ml of 1,4-dioxane, stir and disperse, then add 9g of epoxidized phenolic resin and 0.03g of boron trifluoride ether, react at 90℃ for 12h, filter after the reaction, wash and dry to obtain bentonite-modified phenolic resin.

[0042] (5) Dissolve 1g of hyponitrotriacetic acid and 1.3g of bentonite-modified phenolic resin in 120ml of N,N-dimethylformamide solvent, then add 0.04g of 4-dimethylaminopyridine and 0.03g of N,N-dicyclohexylcarbodiimide, reflux at 110℃ for 12h, precipitate, filter, and wash to obtain carboxyl hyperbranched phenolic resin;

[0043] (6) 1.5g of carboxylated hyperbranched phenolic resin was added to 100ml of N,N-dimethylformamide, stirred evenly, and then 4.2g of β-cyclodextrin and 0.06g of p-toluenesulfonic acid catalyst were added. After reaction, the mixture was filtered and washed to obtain cyclodextrin modified phenolic resin.

[0044] (7) 32g of chitosan, 12g of triazine-modified bentonite, 15g of cyclodextrin-modified phenolic resin and 10g of polyacrylamide were ultrasonically mixed: the ultrasonic frequency was set to 30kHz, the ultrasonic power was set to 250W and the ultrasonic treatment time was set to 20min. After the ultrasonic treatment was completed, an acidic wastewater treatment agent was obtained.

[0045] Example 3

[0046] (1) 11g of γ-glycidyl etheroxypropyltrimethoxysilane modified bentonite was added to a 2% sulfuric acid solution and stirred at 72°C for 16h. After the reaction was completed, the bentonite was filtered, washed and dried to obtain hydroxylated bentonite.

[0047] (2) Add 100 ml of deionized water, 1.5 g of hydroxylated bentonite, and 4.2 g of chloroacetyl chloride to the flask, stir well, add 0.03 g of pyridine catalyst, react at 45 °C for 8 h, then add 1.8 g of 2,4,6-tris(dimethylamino)triazine to carry out quaternization reaction, react at 80 °C for 7 h, filter after completion, wash with ethanol to obtain triazine-modified bentonite;

[0048] (3) Mix 8g of phenolic resin and 13g of epichlorohydrin evenly, react at 86℃ for 8h, then concentrate under reduced pressure and wash to obtain epoxidized phenolic resin.

[0049] (4) Add 6g of hydroxy bentonite to 80ml of 1,4-dioxane, stir and disperse, then add 7g of epoxidized phenolic resin and 0.02g of boron trifluoride ether, react at 82℃ for 10h, filter, wash and dry to obtain bentonite-modified phenolic resin.

[0050] (5) Dissolve 1g of hyponitrotriacetic acid and 1.2g of bentonite-modified phenolic resin in 110ml of N,N-dimethylformamide solvent, then add 0.03g of 4-dimethylaminopyridine and 0.02g of N,N-dicyclohexylcarbodiimide, reflux at 100℃ for 10h, precipitate, filter, and wash to obtain carboxyl hyperbranched phenolic resin;

[0051] (6) 1.3g of carboxylated hyperbranched phenolic resin was added to 92ml of N,N-dimethylformamide, stirred evenly, and then 3.6g of β-cyclodextrin and 0.04g of p-toluenesulfonic acid catalyst were added. After reaction, the mixture was filtered and washed to obtain cyclodextrin modified phenolic resin.

[0052] (7) 26g of chitosan, 9g of triazine-modified bentonite, 13g of cyclodextrin-modified phenolic resin and 8g of polyacrylamide were ultrasonically mixed: the ultrasonic frequency was set to 50kHz, the ultrasonic power to 300W and the ultrasonic treatment time to 25min. After the treatment, an acidic wastewater treatment agent was obtained.

[0053] Comparative Example 1

[0054] The difference between this comparative example and Example 3 is that no triazine-modified bentonite was added.

[0055] Comparative Example 2

[0056] The difference between this comparative example and Example 3 is that no cyclodextrin was added to modify the phenolic resin.

[0057] Comparative Example 1: This comparative example differs from Example 3 in that it uses bentonite instead of triazine-modified bentonite.

[0058] Comparative Example 2: This comparative example differs from Example 3 in that phenolic resin is used instead of cyclodextrin to modify the phenolic resin.

[0059] Comparative Example 3: The difference between this comparative example and Example 3 is that the cyclodextrin component is simply blended with phenolic resin to obtain an acidic wastewater treatment agent.

[0060] Take 200 mL of wastewater into a beaker. The wastewater contains Cd. 2+ and Pb 2+ The initial concentration of each agent was 100 mg / L. An acidic wastewater treatment agent was added to the wastewater, and after ultrasonic dispersion for 5 min, the mixture was shaken on a shaker for 12 h. The supernatant was then collected, and the Cd concentration in the supernatant was determined by ICP. 2+ and Pb 2+ The concentration after adsorption was determined, and the removal rate of heavy metal ions was w = (initial concentration - concentration after adsorption) / initial concentration. The test results are shown in Table 1.

[0061] Table 1: Heavy metal ion removal rate test.

[0062] project Cd2+ removal rate (%) Pb2+ removal rate (%) Example 1 88.6 89.1 Example 2 91.5 91.6 Example 3 89.3 90.8 Comparative Example 1 51.6 53.1 Comparative Example 2 50.7 52.4 Comparative Example 3 48.3 49.6

[0063] As shown in Table 1, Examples 1-3 of the present invention have a better removal effect on heavy metal ions compared with Comparative Examples 1-3, indicating that the removal effect of heavy metal ions is better.

[0064] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An acidic wastewater treatment agent, characterized in that, It includes the following components by weight: 20-32 parts by weight of chitosan, 6-12 parts by weight of triazine-modified bentonite, 7-15 parts by weight of cyclodextrin-modified phenolic resin, and 6-10 parts by weight of polyacrylamide. The preparation method of the triazine-modified bentonite is as follows: (1) Add γ-glycidyl etheroxypropyltrimethoxysilane modified bentonite to sulfuric acid solution, stir and react at 65-80℃, filter, wash and dry to obtain hydroxylated bentonite. (2) Add deionized water, hydroxylated bentonite, and chloroacetyl chloride to the flask, stir evenly, continue to add pyridine catalyst, react at 40-55℃ for 7-10h, then continue to add 2,4,6-tris(dimethylamino)triazine to carry out quaternization reaction, react at 70-90℃ for 6-8h, filter after completion, wash, and obtain triazine-modified bentonite; The preparation method of the cyclodextrin-modified phenolic resin is as follows: S1. Mix phenolic resin and epichlorohydrin evenly, react at 80-95℃ for 6-10h, then concentrate under reduced pressure and wash to obtain epoxidized phenolic resin. S2. Add hydroxy bentonite to 1,4-dioxane, stir and disperse, then add epoxidized phenolic resin and boron trifluoride ether, react at 75-90℃ for 7-12h, filter, wash and dry to obtain bentonite-modified phenolic resin. S3. Dissolve hyponitrotriacetic acid and bentonite-modified phenolic resin in N,N-dimethylformamide solvent, then add 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, and reflux at 90-110℃ for 7-12h. After the reaction, precipitate, filter, and wash to obtain carboxyl hyperbranched phenolic resin. S4. Add carboxyl hyperbranched phenolic resin to N,N-dimethylformamide, stir evenly, then add β-cyclodextrin and p-toluenesulfonic acid catalyst. After reaction, filter and wash to obtain cyclodextrin modified phenolic resin.

2. The acidic wastewater treatment agent according to claim 1, characterized in that, The reaction time in step (1) is 14-18 hours.

3. The acidic wastewater treatment agent according to claim 1, characterized in that, In step (2), the mass ratio of hydroxylated bentonite, chloroacetyl chloride, pyridine catalyst, and 2,4,6-tris(dimethylamino)triazine is 1:2.1-2.6:0.01-0.22:0.8-1.

2.

4. The acidic wastewater treatment agent according to claim 1, characterized in that, The mass ratio of hyponitrotriacetic acid, bentonite-modified phenolic resin, 4-dimethylaminopyridine, and N,N-dicyclohexylcarbodiimide in S3 is 1:0.8-1.3:0.02-0.04:0.01-0.

03.

5. The acidic wastewater treatment agent according to claim 1, characterized in that, The mass ratio of carboxyl hyperbranched phenolic resin, β-cyclodextrin, and p-toluenesulfonic acid catalyst in S4 is 1:2.5-2.8:0.02-0.

04.

6. A method for preparing an acidic wastewater treatment agent as described in any one of claims 1-5, characterized in that, The preparation method of the acidic wastewater treatment agent is as follows: chitosan, triazine-modified bentonite, cyclodextrin-modified phenolic resin, and polyacrylamide are added to a stirrer and stirred for 15-25 minutes to obtain the acidic wastewater treatment agent.