Acidic sewage treatment agent and preparation method thereof

Abstract

The invention relates to the technical field of sewage treatment, and discloses an acidic sewage treatment agent and a preparation method thereof.Chitosan, triazinyl modified bentonite, cyclodextrin modified phenolic resin and polyacrylamide are added into a stirrer and stirred, and the acidic sewage treatment agent is obtained after stirring is finished. Cyclodextrin contained in the cyclodextrin modified phenolic resin has a unique cavity structure, and the cyclodextrin can adsorb heavy metal ions in sewage through the hydrophobic effect in a cavity and the coordination effect of hydroxyl functional groups on the outer side; wherein the phenolic resin is relatively high in phenolic hydroxyl group content and strong in hydrophilicity, and has a relatively good adsorption effect on chromium ions and lead ions in wastewater; the contained triazinyl and bentonite can be used for removing heavy metal ions; and the contained quaternary ammonium salt can also remove heavy metal ions in the sewage through complexation.

Description

Technical Field

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

[0002] Acidic wastewater mainly comes from industries such as metallurgy, metal processing, petrochemicals, chemical fiber, and electroplating. Acidic wastewater contains a large amount of heavy metal ions. If it flows into rivers, it will cause harm to human health. For example, patent CN104787821B discloses an industrial wastewater treatment agent. The wastewater treatment agent in this invention has a fast reaction speed and is non-corrosive to equipment. The method of use is simple and does not change the process flow, and no equipment or additional materials are required. However, the metal ions contained therein will remain in the water and will still cause harm to the human body. Therefore, how to avoid this phenomenon is the key to solving the problem.

[0003] Chitosan is a natural alkaline polysaccharide with excellent biological functions and chemical modification reaction activity, and has good application prospects in sewage treatment. The present invention compounded chitosan with triazine-modified bentonite, cyclodextrin-modified phenolic resin and polyacrylamide to prepare an acidic sewage treatment agent. Summary of the invention

[0004] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides an acidic sewage treatment agent and a preparation method thereof, which can efficiently remove heavy metal ions in acidic sewage.

[0005] (II) Technical solution To achieve the above purpose, the present invention provides the following technical solution: an acidic sewage treatment agent, comprising the following weight components: 20-32 weight parts of chitosan, 6-12 weight parts of triazine-modified bentonite, 7-15 weight parts of cyclodextrin-modified phenolic resin, and 6-10 weight parts of polyacrylamide.

[0006] Preferably, the preparation method of the triazine-modified bentonite is: (1) adding 8-14 g of γ-glycidyloxypropyltrimethoxysilane modified bentonite to a 2-3% sulfuric acid solution, stirring and reacting at 65-80° C., filtering, washing and drying after the reaction is completed to obtain hydroxylated bentonite; (2) Add deionized water, hydroxylated bentonite and chloroacetyl chloride into a flask, stir evenly, continue to add pyridine catalyst, react at 40-55°C for 7-10 hours, then continue to add 2,4,6-tris(dimethylamino)-triazine to carry out quaternization reaction, react at 70-90°C for 6-8 hours, filter after completion, wash with ethanol, and obtain triazine-modified bentonite.

[0007] Preferably, the reaction time in step (1) is 14-18 hours.

[0008] Preferably, in step (2), the mass ratio of hydroxylated bentonite, chloroacetyl chloride, pyridine catalyst, and 2,4,6-tris(dimethylamino)-s-triazine is 1:2.1-2.6:0.01-0.22:0.8-1.2.

[0009] Preferably, the preparation method of the cyclodextrin modified phenolic resin is: S1. The phenolic resin and epichlorohydrin are mixed uniformly, reacted at 80-95 ° C for 6-10h, and then concentrated under reduced pressure and washed to obtain an epoxidized phenolic resin; wherein the mass ratio of the phenolic resin to epichlorohydrin is 6-10:12-15; S2. Add hydroxy bentonite to 1,4-dioxane, stir and disperse, then add epoxidized phenolic resin and boron trifluoride etherate, react at 75-90° C. for 7-12 hours, filter, wash and dry to obtain bentonite-modified phenolic resin; wherein the mass ratio of hydroxy bentonite, epoxidized phenolic resin and boron trifluoride etherate is 4-8:5-8:0.01-0.03; S3. dissolving nitrilotriacetic acid and bentonite-modified phenolic resin in N,N-dimethylformamide solvent, then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, reflux at 90-110° C. for 7-12 h, precipitating, filtering, and washing after the reaction to obtain a carboxyl hyperbranched phenolic resin; S4. Add the carboxyl hyperbranched phenolic resin to N,N-dimethylformamide, stir evenly, then add β-cyclodextrin and p-toluenesulfonic acid catalyst, filter and wash after the reaction to obtain cyclodextrin-modified phenolic resin.

[0010] Preferably, the mass ratio of nitrilotriacetic 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.

[0011] Preferably, the mass ratio of the carboxyl hyperbranched phenolic resin, β-cyclodextrin and p-toluenesulfonic acid catalyst in S4 is 1:2.5-2.8:0.02-0.04.

[0012] Preferably, the preparation method of the acidic sewage treatment agent is: 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 set to 200-300W, and the ultrasonic treatment time is set to 15-25min, and the acidic sewage treatment agent is obtained after the end.

[0013] (III) Beneficial effects The invention adds chitosan, triazine-modified bentonite, cyclodextrin-modified phenolic resin and polyacrylamide into a stirrer, and stirs to obtain an acidic sewage treatment agent.

[0014] γ-glycidyloxypropyltrimethoxysilane modified bentonite is added to a sulfuric acid solution for hydrolysis reaction to obtain hydroxylated bentonite; the hydroxyl group in the hydroxylated bentonite reacts with the acyl chloride in chloroacetyl chloride to generate an ester group, and a chlorine group is introduced at the same time, and further reacts with the tertiary amine group in 2,4,6-tris(dimethylamino)-triazine to generate a quaternary ammonium salt, and a triazine group is introduced, thereby obtaining a triazine-modified bentonite; a phenolic resin reacts with epichlorohydrin to obtain an epoxidized phenolic resin, and a hydroxyl group in the hydroxylated bentonite and an epoxy group in the epoxidized phenolic resin are subjected to an addition reaction to generate a hydroxyl group, thereby obtaining a bentonite-modified phenolic resin; a carboxyl group in nitrilotriacetic acid and a hydroxyl group in the bentonite-modified phenolic resin are subjected to an esterification reaction to obtain a carboxyl hyperbranched phenolic resin, and then β-cyclodextrin is added thereto for end-capping to obtain a cyclodextrin-modified phenolic resin.

[0015] The cyclodextrin contained in the cyclodextrin modified phenolic resin has a unique cavity structure. For heavy metal ions in sewage, cyclodextrin can adsorb heavy metal ions through the hydrophobic effect in its cavity and the coordination effect of the hydroxyl functional group on the outside; the phenolic resin has a high phenolic hydroxyl content and strong hydrophilicity, and has a good adsorption effect on chromium ions and lead ions in wastewater; the triazine group contained in it is a six-membered heterocyclic structure containing three nitrogen atoms. These nitrogen atoms can be used as coordination atoms to form a stable coordination with metal ions due to their strong electronegativity, and the bentonite therein has a large specific surface area and good adsorption capacity. The cations between the montmorillonite layers therein can be well exchanged with the chromium ions and lead ions in the wastewater, thereby removing the heavy metal ions; the quaternary ammonium salt contained therein can also remove the heavy metal ions in the sewage through the complexation effect; and the cyclodextrin modified phenolic resin contains a hyperbranched structure, which is capped with beta-cyclodextrin, thereby increasing its substitution degree and being able to better adsorb heavy metal ions. DETAILED DESCRIPTION

[0016] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not 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.

[0017] The raw materials used in the embodiments of the present invention are as follows: γ-Glycidyloxypropyltrimethoxysilane modified bentonite was prepared according to the literature "Adsorption performance of tetraethylenepentamine grafted bentonite on acid red GR" (Chemical Industry Progress, Vol. 40, No. 5, 2021): Add 2 g of bentonite to 100 mL of 7% hydrochloric acid solution, heat and reflux at 80 ° C for acidification, filter, wash with deionized water and dry to obtain acid-modified bentonite. Disperse 2 g of acid-modified bentonite in 150 mL of ethanol, add 8 g of γ-glycidyloxypropyltrimethoxysilane, stir and reflux at 90 ° C in a nitrogen atmosphere for 24 hours, filter, wash with ethanol and dry to obtain γ-glycidyloxypropyltrimethoxysilane-modified bentonite.

[0018] Example 1 (1) 8 g of γ-glycidyloxypropyltrimethoxysilane-modified bentonite was added to a 2% sulfuric acid solution, and the mixture was stirred at 65° C. for 14 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain hydroxylated bentonite. (2) Add 80 ml of deionized water, 1 g of hydroxylated bentonite, and 2.1 g of chloroacetyl chloride into a flask, stir evenly, continue to add 0.01 g of pyridine catalyst, react at 40 ° C for 7 h, then continue to add 0.8 g of 2,4,6-tris(dimethylamino)-triazine to carry out quaternization reaction, react at 70 ° C for 6 h, filter after completion, wash with ethanol, and obtain triazine-modified bentonite; (3) 6 g of phenolic resin and 12 g of epichlorohydrin were mixed evenly, reacted at 80° C. for 6 h, and then concentrated under reduced pressure and washed to obtain epoxidized phenolic resin; (4) Add 4 g of hydroxy bentonite to 70 ml of 1,4-dioxane, stir to disperse, then add 5 g of epoxidized phenolic resin and 0.01 g of boron trifluoride etherate, react at 75 °C for 7 h, filter, wash and dry to obtain bentonite-modified phenolic resin; (5) dissolving 1 g of nitrilotriacetic acid and 0.8 g of bentonite-modified phenolic resin in 100 ml of N,N-dimethylformamide solvent, then adding 0.02 g of 4-dimethylaminopyridine and 0.01 g of N,N-dicyclohexylcarbodiimide, and refluxing at 90° C. for 7 h. After the reaction, precipitating, filtering, and washing to obtain a carboxyl hyperbranched phenolic resin; (6) Add 1 g of carboxyl hyperbranched phenolic resin to 85 ml of N,N-dimethylformamide, stir evenly, add 2.5 g of β-cyclodextrin and 0.02 g of p-toluenesulfonic acid catalyst, filter and wash after reaction, and obtain cyclodextrin-modified phenolic resin; (7) Ultrasonic mixing of 20 g of chitosan, 6 g of triazine-modified bentonite, 7 g of cyclodextrin-modified phenolic resin, and 6 g of polyacrylamide: the ultrasonic frequency was set to 20 kHz, the ultrasonic power was set to 200 W, and the ultrasonic treatment time was set to 15 min. After the mixing, an acidic sewage treatment agent was obtained.

[0019] Example 2 (1) 14 g of γ-glycidyloxypropyltrimethoxysilane-modified bentonite was added to a 3% sulfuric acid solution, and the mixture was stirred at 80° C. for 18 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain hydroxylated bentonite. (2) Add 120 ml of deionized water, 2 g of hydroxylated bentonite, and 5.2 g of chloroacetyl chloride into a flask, stir evenly, continue to add 0.44 g of pyridine catalyst, react at 55 ° C for 10 h, then continue to add 2.4 g of 2,4,6-tris(dimethylamino)-triazine to carry out quaternization reaction, react at 90 ° C for 8 h, filter after completion, wash with ethanol, and obtain triazine-modified bentonite; (3) 10 g of phenolic resin and 15 g of epichlorohydrin were mixed evenly, reacted at 95 °C for 10 h, and then concentrated under reduced pressure and washed to obtain epoxidized phenolic resin; (4) Add 8 g of hydroxy bentonite to 90 ml of 1,4-dioxane, stir to disperse, then add 9 g of epoxidized phenolic resin and 0.03 g of boron trifluoride etherate, react at 90 ° C for 12 h, filter after reaction, wash and dry to obtain bentonite-modified phenolic resin; (5) dissolving 1 g of nitrilotriacetic acid and 1.3 g of bentonite-modified phenolic resin in 120 ml of N,N-dimethylformamide solvent, then adding 0.04 g of 4-dimethylaminopyridine and 0.03 g of N,N-dicyclohexylcarbodiimide, and refluxing at 110° C. for 12 h. After the reaction, precipitating, filtering, and washing to obtain a carboxyl hyperbranched phenolic resin; (6) Add 1.5 g of carboxyl hyperbranched phenolic resin to 100 ml of N,N-dimethylformamide, stir evenly, add 4.2 g of β-cyclodextrin and 0.06 g of p-toluenesulfonic acid catalyst, filter and wash after reaction, and obtain cyclodextrin-modified phenolic resin; (7) 32 g of chitosan, 12 g of triazine-modified bentonite, 15 g of cyclodextrin-modified phenolic resin, and 10 g of polyacrylamide were ultrasonically mixed: the ultrasonic frequency was set to 30 kHz, the ultrasonic power was set to 250 W, and the ultrasonic treatment time was set to 20 min. After the mixture was mixed, an acidic sewage treatment agent was obtained.

[0020] Example 3 (1) 11 g of γ-glycidyloxypropyltrimethoxysilane-modified bentonite was added to a 2% sulfuric acid solution, and the mixture was stirred at 72°C for 16 h. After the reaction was completed, the mixture was filtered, washed and dried to obtain hydroxylated bentonite. (2) Add 100 ml of deionized water, 1.5 g of hydroxylated bentonite, and 4.2 g of chloroacetyl chloride into a flask, stir evenly, continue to add 0.03 g of pyridine catalyst, react at 45 ° C for 8 h, then continue to 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, and obtain triazine-modified bentonite; (3) 8 g of phenolic resin and 13 g of epichlorohydrin were mixed evenly, reacted at 86 °C for 8 h, and then concentrated under reduced pressure and washed to obtain epoxidized phenolic resin; (4) Add 6 g of hydroxy bentonite to 80 ml of 1,4-dioxane, stir to disperse, then add 7 g of epoxidized phenolic resin and 0.02 g of boron trifluoride etherate, react at 82 °C for 10 h, filter after reaction, wash and dry to obtain bentonite-modified phenolic resin; (5) Dissolve 1 g of nitrilotriacetic acid and 1.2 g of bentonite-modified phenolic resin in 110 ml of N,N-dimethylformamide solvent, then add 0.03 g of 4-dimethylaminopyridine and 0.02 g of N,N-dicyclohexylcarbodiimide, and reflux at 100 °C for 10 h. After the reaction, precipitate, filter, and wash to obtain a carboxyl hyperbranched phenolic resin; (6) Add 1.3 g of carboxyl hyperbranched phenolic resin to 92 ml of N,N-dimethylformamide, stir evenly, add 3.6 g of β-cyclodextrin and 0.04 g of p-toluenesulfonic acid catalyst, filter and wash after reaction, and obtain cyclodextrin-modified phenolic resin; (7) Ultrasonic mixing of 26 g of chitosan, 9 g of triazine-modified bentonite, 13 g of cyclodextrin-modified phenolic resin, and 8 g of polyacrylamide: the ultrasonic frequency was set to 50 kHz, the ultrasonic power was set to 300 W, and the ultrasonic treatment time was set to 25 min. After the mixture was mixed, an acidic sewage treatment agent was obtained.

[0021] Comparative Example 1 This comparative example is different from Example 3 in that no triazine-modified bentonite is added.

[0022] Comparative Example 2 The difference between this comparative example and Example 3 is that no cyclodextrin-modified phenolic resin is added.

[0023] Comparative Example 1: This comparative example is compared with Example 3, except that bentonite is used instead of triazine-modified bentonite.

[0024] Comparative Example 2: This comparative example is compared with Example 3, except that phenolic resin is used instead of cyclodextrin-modified phenolic resin. Comparative Example 3: This comparative example is different from Example 3 in that the cyclodextrin component is simply blended with the phenolic resin to obtain the acidic sewage treatment agent.

[0025] Take 200mL of wastewater into a beaker. 2+ , and Pb 2+ The initial concentration of the wastewater was 100 mg / L. Acidic sewage treatment agent was added to the wastewater, and after ultrasonic dispersion for 5 minutes, it was placed on a shaker for 12 hours. The supernatant was taken and the Cd content in the supernatant was determined by ICP. 2+ and Pb 2+ The concentration after adsorption, the removal rate of heavy metal ions w = (initial concentration-concentration after adsorption) / initial concentration, the test results are shown in Table 1.

[0026] Table 1: Heavy metal ion removal rate test.

[0027] 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 It can be seen from Table 1 that Examples 1-3 of the present invention have better removal effects on heavy metal ions than Comparative Examples 1-3, indicating that the heavy metal ion removal effect is better.

[0028] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0029] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. An acidic sewage treatment agent, characterized in that: The invention comprises 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.

2. The acidic sewage treating agent according to claim 1, characterized in that: The preparation method of the triazine-modified bentonite is as follows: (1) adding γ-glycidyloxypropyltrimethoxysilane modified bentonite to a sulfuric acid solution, stirring and reacting at 65-80° C., filtering, washing and drying after the reaction is completed to obtain hydroxylated bentonite; (2) Add deionized water, hydroxylated bentonite and chloroacetyl chloride into a flask, stir evenly, continue to add pyridine catalyst, react at 40-55°C for 7-10 hours, then continue to add 2,4,6-tris(dimethylamino)-triazine to carry out quaternization reaction, react at 70-90°C for 6-8 hours, filter and wash after completion to obtain triazine-modified bentonite.

3. The acidic sewage treating agent according to claim 2, characterized in that: The reaction time in step (1) is 14-18 hours.

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

2.

5. The acidic sewage treating agent according to claim 1, characterized in that: The preparation method of the cyclodextrin modified phenolic resin is as follows: S1. The phenolic resin and epichlorohydrin are mixed evenly, reacted at 80-95°C for 6-10h, and then concentrated under reduced pressure and washed to obtain an epoxidized phenolic resin; S2. Add hydroxy bentonite to 1,4-dioxane, stir and disperse, then add epoxidized phenolic resin and boron trifluoride etherate, react at 75-90° C. for 7-12 hours, filter, wash and dry to obtain bentonite-modified phenolic resin; S3. dissolving nitrilotriacetic acid and bentonite-modified phenolic resin in N,N-dimethylformamide solvent, then adding 4-dimethylaminopyridine and N,N-dicyclohexylcarbodiimide, reflux at 90-110° C. for 7-12 h, precipitating, filtering, and washing after the reaction to obtain a carboxyl hyperbranched phenolic resin; S4. Add the carboxyl hyperbranched phenolic resin to N,N-dimethylformamide, stir evenly, then add β-cyclodextrin and p-toluenesulfonic acid catalyst, filter and wash after the reaction to obtain cyclodextrin-modified phenolic resin.

6. The acidic sewage treating agent according to claim 5, characterized in that: The mass ratio of nitrilotriacetic 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.

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

04.

8. A method for preparing an acidic sewage treatment agent according to any one of claims 1 to 7, characterized in that: The preparation method of the acidic sewage 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 set to 200-300W, and the ultrasonic treatment time is set to 15-25min, and the acidic sewage treatment agent is obtained after the end.