Composite flocculant containing cationic etherifying agent and preparation method thereof

Abstract

The invention relates to the technical field of flocculants, in particular to a composite flocculant containing a cationic etherifying agent and a preparation method of the composite flocculant, and the composite flocculant is prepared from the following raw materials in parts by weight: 15-20 parts of carboxymethyl guar gum, 12-15 parts of cationic konjac glucomannan, 1.2-1.5 parts of the cationic etherifying agent, 1.8-2.2 parts of a magnetic polysilicate metal salt flocculant and 0.2-0.3 part of a preservative. According to the present invention, by compounding the flocculant, the flocculated floc has magnetism and can be recovered and repeatedly utilized, and the photoresponse azobenzene structure is grafted in the cationic konjac glucomannan, such that the controllable pollutant aggregation and separation can be achieved, and the good flocculation performance can be maintained after the composite flocculant is repeatedly recovered and repeatedly utilized.

Description

Technical Field

[0001] The present invention relates to the technical field of flocculants, and particularly relates to a composite flocculant containing a cationic etherifying agent and a preparation method thereof. Background Art

[0002] The occurrence of water resource pollution is caused by pollutants discharged from various pollution sources entering the water body. Such pollutants include soluble substances and insoluble impurities. These two substances interact with each other in water to form charged colloidal particles, so it is difficult to separate them by simple physical sedimentation. Currently, it is usually chosen to add a flocculant to the water sample, so as to change the stability of the colloidal particles in the water sample, make them destabilize and flocculate, and achieve the purpose of separation and purification. For example, in the patent CN112919602B "Guar gum-inorganic salt hybrid green flocculant for enhanced dewatering of sediment and heavy metal fixation and its preparation method", by using sulfonated guar gum as a raw material, modifying it, and then compounding it with inorganic aluminum salts or iron salts, a good flocculation effect is achieved. However, it cannot be recovered after flocculation and cannot meet the market demand. Summary of the Invention

[0003] The purpose of the present invention is to provide a composite flocculant containing a cationic etherifying agent and a preparation method thereof. By compounding carboxymethyl guar gum, cationic konjac glucomannan, a cationic etherifying agent, and a magnetic polysilicate metal salt flocculant, the flocs after flocculation have magnetism and can be recovered and reused. And because the cationic konjac glucomannan is grafted with a photo-responsive azobenzene structure, controllable pollutant aggregation and separation are realized, ensuring that the composite flocculant can still maintain good flocculation performance after being recycled and reused multiple times.

[0004] The purpose of the present invention can be achieved by the following technical solutions: A preparation method of a composite flocculant containing a cationic etherifying agent, which includes the following steps: Step S1: Weigh the following raw materials in parts by weight: 15 - 20 parts of carboxymethyl guar gum, 12 - 15 parts of cationic konjac glucomannan, 1.2 - 1.5 parts of cationic etherifying agent, 1.8 - 2.2 parts of magnetic polysilicate metal salt flocculant, and 0.2 - 0.3 parts of preservative;

[0005] Step S2: Mix the cationic konjac glucomannan, the preservative, and the magnetic polysilicate metal salt flocculant, stir at a temperature of 40°C for 15 - 20 minutes, then add the carboxymethyl guar gum and the cationic etherifying agent, and raise the temperature to 50°C, continue to stir for 1.5 - 2 hours, and age for 12 hours to obtain a composite flocculant containing a cationic etherifying agent;

[0006] The carboxymethyl guar gum is the carboxymethyl guar gum produced by Jiangsu Juchuang Biotechnology Co., Ltd., with a specification of 100 mesh and a product number of 5581;

[0007] The cationic etherifying agent is one or more of 3-chloro-2-hydroxypropyl trimethyl ammonium chloride or glycidyl trimethyl ammonium chloride;

[0008] The preservative is okselic potassium sorbate;

[0009] The cationic konjac glucomannan is prepared by the following steps:

[0010] Step A1: Mix azobenzene-4-benzoic acid, 3-dimethylaminopropylamine and tetrahydrofuran, stir and add N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole at a stirring rate of 160 - 180 rpm under room temperature conditions, react for 20 - 24 h, distill under reduced pressure, recrystallize with acetone, filter by suction, wash, and dry to obtain Intermediate 1. Mix Intermediate 1, hydrochloric acid solution and ethanol, stir and add epichlorohydrin at a stirring rate of 160 - 180 rpm under room temperature conditions, stir for 10 - 15 min, heat up to 60 - 65 °C, react for 2 - 2.5 h, distill under reduced pressure, recrystallize with acetone, filter by suction, wash, and dry to obtain Intermediate 2;

[0011] The dosage ratio of azobenzene-4-benzoic acid, 3-dimethylaminopropylamine, tetrahydrofuran, N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole is 1.1 - 1.15 g : 0.45 - 0.48 g : 25 - 30 mL : 0.95 - 0.98 g : 0.62 - 0.65 g; the mass fraction of the hydrochloric acid solution is 35%, and the dosage ratio of Intermediate 1, hydrochloric acid solution, ethanol and epichlorohydrin is 2.4 - 2.6 g : 5 - 8 mL : 35 - 40 mL : 3.8 mL - 4.1 mL;

[0012] During the reaction process, under the action of N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole, the carboxyl group in azobenzene-4-benzoic acid reacts with the primary amino group in 3-dimethylaminopropylamine to form an amide structure, obtaining Intermediate 1. Then, the tertiary amine structure in Intermediate 1 reacts with epichlorohydrin to form a quaternary ammonium salt structure, obtaining Intermediate 2.

[0013] Step A2: Mix Intermediate 2, phenothiazine and ethanol, stir and add dimethylaminoethyl acrylate at a stirring rate of 120 - 140 rpm under the condition of a temperature of 60 - 65 °C, react for 20 - 24 h, distill under reduced pressure, recrystallize with acetone / ethyl acetate, filter by suction, wash, and dry to obtain the cationic modifier;

[0014] The dosage ratio of Intermediate 2, phenothiazine, ethanol and dimethylaminoethyl acrylate is 2.5 - 2.6 g : 0.006 - 0.008 g : 45 - 50 mL : 0.78 - 0.79 mL;

[0015] During the reaction process, the chlorine in intermediate 2 reacts with the tertiary amine structure in dimethylaminoethyl acrylate to form a quaternary ammonium salt structure and introduce a double bond, thereby obtaining a cationic modifier.

[0016]

[0017] Step A3: Mix konjac glucomannan and deionized water, stir at a stirring rate of 120 - 140 rpm and a temperature of 40 °C for 10 - 15 min, then under nitrogen protection, stir and add ammonium cerium nitrate and the cationic modifier, react for 4 - 5 h, precipitate with acetone, filter by suction, wash, and dry to obtain cationic konjac glucomannan;

[0018] The dosage ratio of konjac glucomannan, deionized water, ammonium cerium nitrate, and the cationic modifier is 1.2 - 1.4 g : 120 - 130 mL : 0.042 - 0.045 g : 3.4 - 3.6 g;

[0019] During the reaction process, using ammonium cerium nitrate as an initiator, konjac glucomannan as a substrate, and the cationic modifier as a monomer, through free radical graft copolymerization reaction, the cationic modifier is grafted onto konjac glucomannan to obtain cationic konjac glucomannan;

[0020] The konjac glucomannan is from Guchen Biotech, and the product number is GC18123.

[0021] The magnetic polysilicate metal salt flocculant is prepared through the following steps:

[0022] Mix magnetic iron oxide particles, sodium metasilicate nonahydrate, and deionized water, stir and add sulfuric acid solution and sodium hydroxide solution at a stirring rate of 120 - 140 rpm and a temperature of 40 °C, adjust the pH value to 3, stir for 2 - 3 h, age for 24 h, then add aluminum sulfate solution and sodium tetraborate solution, and stir at a stirring rate of 120 - 140 rpm and a temperature of 40 °C for 2 - 3 h to obtain the magnetic polysilicate metal salt flocculant;

[0023] The mass fraction of the sulfuric acid solution is 30%, the mass fraction of the sodium hydroxide solution is 15%, the molar concentration of the aluminum sulfate solution is 0.3 mol / L, the molar concentration of the sodium tetraborate solution is 0.15 mol / L, and the dosage ratio of magnetic iron oxide particles, sodium metasilicate nonahydrate, deionized water, aluminum sulfate solution, and sodium tetraborate solution is 1.2 - 1.4 g : 14 - 15 g : 300 - 350 mL : 40 - 45 mL : 5 - 8 mL;

[0024] The magnetic iron oxide particles are magnetic iron oxide from Zhongke Yannuo, with a specification of 50 - 300 nm;

[0025] During the reaction process, using magnetic iron oxide particles as the core, under acidic conditions, sodium metasilicate nonahydrate polymerizes to wrap the magnetic iron oxide particle core, and using aluminum sulfate solution and sodium tetraborate solution as the aluminum source and boron source, aluminum ions and boron ions are introduced to modify it, and a magnetic polysilicate metal salt flocculant is prepared.

[0026] Advantages of the present invention: The present invention discloses a composite flocculant containing a cationic etherifying agent and a preparation method thereof. By compounding carboxymethyl guar gum, cationic konjac glucomannan, a cationic etherifying agent, and a magnetic polysilicate metal salt flocculant, the flocs after flocculation have magnetism and can be recycled and reused. Moreover, since the cationic konjac glucomannan is grafted with a photo-responsive azobenzene structure, controllable pollutant aggregation and separation are achieved, ensuring that the composite flocculant can still maintain good flocculation performance after being recycled and reused multiple times;

[0027] Due to the large number of carboxymethyl structures and quaternary ammonium structures in carboxymethyl guar gum and cationic konjac glucomannan, they can form a complex through electrostatic attraction, thereby enhancing the charge neutralization efficiency. And because carboxymethyl guar gum has a branched structure and cationic konjac glucomannan has a linear main chain, their complex forms flocs, further improving the flocculation effect. Also, due to the large number of boron ions in the magnetic polysilicate metal salt flocculant, they can combine with the cis adjacent hydroxyl groups in guar gum and konjac glucomannan, thereby grafting into the flocs, not only exerting the effect of inorganic-organic compounding, but also making the flocs magnetic for recycling. And the cationic konjac glucomannan is grafted with a photo-responsive azobenzene structure, and its azobenzene structure undergoes reversible cis-trans isomerization under ultraviolet and visible light irradiation, thereby changing the charge distribution and molecular configuration of the flocculant, so that the composite flocculant is deflocculated during the recycling process, releasing pollutants and improving the recycling performance of the flocculant. Description of the Drawings

[0028] Figure 1 It is the 1H NMR spectrum of Intermediate 1 in Example 3;

[0029] Figure 2 It is the 1H NMR spectrum of Intermediate 2 in Example 3;

[0030] Figure 3 It is the 1H NMR spectrum of the cationic modifier in Example 3. Detailed Embodiments

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

[0032] Example 1. A preparation method of a composite flocculant containing a cationic etherifying agent, which comprises the following steps: Step S1: Weigh the following raw materials by weight: 15 parts of carboxymethyl guar gum, 12 parts of cationic konjac glucomannan, 1.2 parts of cationic etherifying agent, 1.8 parts of magnetic polysilicate metal salt flocculant, and 0.2 part of preservative;

[0033] Step S2: Mix the cationic konjac glucomannan, preservative, and magnetic polysilicate metal salt flocculant, stir at 40 °C for 15 min, then add carboxymethyl guar gum and cationic etherifying agent, raise the temperature to 50 °C, continue stirring for 1.5 h, and age for 12 h to obtain a composite flocculant containing a cationic etherifying agent;

[0034] The carboxymethyl guar gum is the carboxymethyl guar gum produced by Jiangsu Juchuang Biotechnology Co., Ltd., with a specification of 100 mesh and a product number of 5581;

[0035] The cationic etherifying agent is 3-chloro-2-hydroxypropyltrimethylammonium chloride;

[0036] The preservative is Okaysorbate;

[0037] The cationic konjac glucomannan is prepared by the following steps:

[0038] Step A1: Mix azobenzene-4-carboxylic acid, 3-dimethylaminopropylamine, and tetrahydrofuran, stir and add N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole at a stirring rate of 160 rpm at room temperature, react for 20 h, perform vacuum distillation, recrystallize with acetone, filter, wash, and dry to obtain Intermediate 1. Mix Intermediate 1, hydrochloric acid solution, and ethanol, stir and add epichlorohydrin at a stirring rate of 160 rpm at room temperature, stir for 10 min, raise the temperature to 60 °C, react for 2 h, perform vacuum distillation, recrystallize with acetone, filter, wash, and dry to obtain Intermediate 2;

[0039] The dosage ratio of azobenzene-4-carboxylic acid, 3-dimethylaminopropylamine, tetrahydrofuran, N,N'-dicyclohexylcarbodiimide, and 1-hydroxybenzotriazole is 1.1 g: 0.45 g: 25 mL: 0.95 g: 0.62 g; the mass fraction of the hydrochloric acid solution is 35%, and the dosage ratio of Intermediate 1, hydrochloric acid solution, ethanol, and epichlorohydrin is 2.4 g: 5 mL: 35 mL: 3.8 mL;

[0040] Step A2: Mix Intermediate 2, phenothiazine, and ethanol, stir and add dimethylaminoethyl acrylate at a stirring rate of 120 rpm at 60 °C, react for 20 h, perform vacuum distillation, recrystallize with acetone / ethyl acetate, filter, wash, and dry to obtain a cationic modifier;

[0041] The dosage ratio of intermediate 2, phenothiazine, ethanol and dimethylaminoethyl acrylate is 2.5 g: 0.006 g: 45 mL: 0.78 mL;

[0042] Step A3: Mix konjac glucomannan and deionized water, stir at a stirring rate of 120 rpm and a temperature of 40 °C for 10 min, then under nitrogen protection, stir and add ammonium cerium nitrate and cationic modifier, react for 4 h, precipitate with acetone, filter, wash, and dry to obtain cationic konjac glucomannan;

[0043] The dosage ratio of konjac glucomannan, deionized water, ammonium cerium nitrate and cationic modifier is 1.2 g: 120 mL: 0.042 g: 3.4 g;

[0044] The konjac glucomannan is from Guchen Biotech, and the product number is GC18123;

[0045] The magnetic polysilicate metal salt flocculant is prepared by the following steps:

[0046] Mix magnetic iron oxide particles, sodium metasilicate nonahydrate and deionized water, stir and add sulfuric acid solution and sodium hydroxide solution at a stirring rate of 120 rpm and a temperature of 40 °C, adjust the pH value to 3, stir for 2 h, age for 24 h, then add aluminum sulfate solution and sodium tetraborate solution, and stir at a stirring rate of 120 rpm and a temperature of 40 °C for 3 h to obtain magnetic polysilicate metal salt flocculant;

[0047] The mass fraction of the sulfuric acid solution is 30%, the mass fraction of the sodium hydroxide solution is 15%, the molar concentration of the aluminum sulfate solution is 0.3 mol / L, the molar concentration of the sodium tetraborate solution is 0.15 mol / L, and the dosage ratio of magnetic iron oxide particles, sodium metasilicate nonahydrate, deionized water, aluminum sulfate solution and sodium tetraborate solution is 1.4 g: 14 g: 350 mL: 40 mL: 8 mL;

[0048] The magnetic iron oxide particles are magnetic iron oxide from Zhongke Yannuo, with a specification of 50 - 300 nm.

[0049] Example 2 A preparation method of a composite flocculant containing a cationic etherifying agent, which includes the following steps: Step S1: Weigh the following raw materials in parts by weight: 20 parts of carboxymethyl guar gum, 12 parts of cationic konjac glucomannan, 1.5 parts of cationic etherifying agent, 1.8 parts of magnetic polysilicate metal salt flocculant and 0.3 part of preservative;

[0050] Step S2: Mix cationic konjac glucomannan, preservative and magnetic polysilicate metal salt flocculant, stir for 20 min at a temperature of 40 °C, then add carboxymethyl guar gum and cationic etherifying agent, raise the temperature to 50 °C, continue to stir for 1.5 h, and age for 12 h to obtain a composite flocculant containing cationic etherifying agent;

[0051] The carboxymethyl guar gum is the carboxymethyl guar gum produced by Jiangsu Juchuang Bioengineering Co., Ltd., with a specification of 100 mesh and a product number of 5581;

[0052] The cationic etherifying agent is glycidyltrimethylammonium chloride;

[0053] The preservative is Okaysorbate;

[0054] The cationic konjac glucomannan is prepared by the following steps:

[0055] Step A1: Mix azobenzene-4-benzoic acid, 3-dimethylaminopropylamine and tetrahydrofuran, stir and add N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole at a stirring rate of 180 rpm and at room temperature, react for 20 h, carry out vacuum distillation, recrystallize with acetone, filter by suction, wash, and dry to obtain Intermediate 1. Mix Intermediate 1, hydrochloric acid solution and ethanol, stir and add epichlorohydrin at a stirring rate of 160 rpm and at room temperature, stir for 15 min, raise the temperature to 60 °C, react for 2.5 h, carry out vacuum distillation, recrystallize with acetone, filter by suction, wash, and dry to obtain Intermediate 2;

[0056] The dosage ratio of azobenzene-4-benzoic acid, 3-dimethylaminopropylamine, tetrahydrofuran, N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole is 1.1 g: 0.48 g: 25 mL: 0.95 g: 0.65 g; the mass fraction of the hydrochloric acid solution is 35%, and the dosage ratio of Intermediate 1, hydrochloric acid solution, ethanol and epichlorohydrin is 2.6 g: 5 mL: 35 mL: 4.1 mL;

[0057] Step A2: Mix Intermediate 2, phenothiazine and ethanol, stir and add dimethylaminoethyl acrylate at a stirring rate of 120 rpm and at a temperature of 60 °C, react for 24 h, carry out vacuum distillation, recrystallize with acetone / ethyl acetate, filter by suction, wash, and dry to obtain a cationic modifier;

[0058] The dosage ratio of Intermediate 2, phenothiazine, ethanol and dimethylaminoethyl acrylate is 2.5 g: 0.008 g: 45 mL: 0.78 mL;

[0059] Step A3: Mix konjac glucomannan and deionized water, stir for 10 min at a stirring rate of 140 rpm and a temperature of 40°C, then under nitrogen protection, stir and add ammonium cerium nitrate and cationic modifier, react for 4 h, precipitate with acetone, filter by suction, wash, and dry to obtain cationic konjac glucomannan;

[0060] The dosage ratio of konjac glucomannan, deionized water, ammonium cerium nitrate and cationic modifier is 1.4 g: 120 mL: 0.042 g: 3.6 g;

[0061] The konjac glucomannan comes from Guchen Biology, and the product number is GC18123;

[0062] The magnetic polysilicate metal salt flocculant is prepared by the following steps:

[0063] Mix magnetic iron oxide particles, sodium metasilicate nonahydrate and deionized water, stir and add sulfuric acid solution and sodium hydroxide solution at a stirring rate of 120 rpm and a temperature of 40°C, adjust the pH value to 3, stir for 3 h, age for 24 h, then add aluminum sulfate solution and sodium tetraborate solution, and stir for 3 h at a stirring rate of 120 rpm and a temperature of 40°C to obtain magnetic polysilicate metal salt flocculant;

[0064] The mass fraction of the sulfuric acid solution is 30%, the mass fraction of the sodium hydroxide solution is 15%, the molar concentration of the aluminum sulfate solution is 0.3 mol / L, the molar concentration of the sodium tetraborate solution is 0.15 mol / L, and the dosage ratio of magnetic iron oxide particles, sodium metasilicate nonahydrate, deionized water, aluminum sulfate solution and sodium tetraborate solution is 1.4 g: 14 g: 350 mL: 40 mL: 8 mL;

[0065] The magnetic iron oxide particles are magnetic iron oxide from Zhongke Yannuo, with a specification of 50 - 300 nm.

[0066] Example 3 A preparation method of a composite flocculant containing cationic etherifying agent, which includes the following steps: Step S1: Weigh the following raw materials in parts by weight: 20 parts of carboxymethyl guar gum, 15 parts of cationic konjac glucomannan, 1.5 parts of cationic etherifying agent, 2.2 parts of magnetic polysilicate metal salt flocculant and 0.3 part of preservative;

[0067] Step S2: Mix cationic konjac glucomannan, preservative and magnetic polysilicate metal salt flocculant, stir for 20 min at a temperature of 40°C, then add carboxymethyl guar gum and cationic etherifying agent, and raise the temperature to 50°C, continue to stir for 2 h, and age for 12 h to obtain a composite flocculant containing cationic etherifying agent;

[0068] The carboxymethyl guar gum is the carboxymethyl guar gum produced by Jiangsu Juchuang Bioengineering Co., Ltd., with a specification of 100 mesh and a product number of 5581;

[0069] The cationic etherifying agent is 3-chloro-2-hydroxypropyltrimethylammonium chloride;

[0070] The preservative is Okaysorbate;

[0071] The cationic konjac glucomannan is prepared by the following steps:

[0072] Step A1: Mix azobenzene-4-benzoic acid, 3-dimethylaminopropylamine and tetrahydrofuran, stir and add N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole at a stirring rate of 180 rpm and at room temperature, react for 24 h, carry out vacuum distillation, recrystallize with acetone, filter by suction, wash, and dry to obtain Intermediate 1. Mix Intermediate 1, hydrochloric acid solution and ethanol, stir and add epichlorohydrin at a stirring rate of 180 rpm and at room temperature, stir for 15 min, heat up to 65 °C, react for 2.5 h, carry out vacuum distillation, recrystallize with acetone, filter by suction, wash, and dry to obtain Intermediate 2;

[0073] The dosage ratios of azobenzene-4-benzoic acid, 3-dimethylaminopropylamine, tetrahydrofuran, N,N'-dicyclohexylcarbodiimide and 1-hydroxybenzotriazole are 1.15 g: 0.48 g: 30 mL: 0.98 g: 0.65 g; the mass fraction of the hydrochloric acid solution is 35%, and the dosage ratios of Intermediate 1, hydrochloric acid solution, ethanol and epichlorohydrin are 2.6 g: 8 mL: 40 mL: 4.1 mL;

[0074] Figure 1 is the 1H NMR spectrum of Intermediate 1 in Example 3. From Figure 1 it can be seen that an obvious [-NH-] characteristic peak appears at δ = 8.4 - 8.5, indicating that azobenzene-4-benzoic acid and 3-dimethylaminopropylamine have successfully reacted;

[0075] Figure 2 is the 1H NMR spectrum of Intermediate 2 in Example 3. From Figure 2 it can be seen that an obvious [-CH3-] characteristic peak appears at δ = 3.2 - 3.3, and an obvious [-OH] characteristic peak appears at δ = 6.1 - 6.2, indicating that Intermediate 1 has successfully reacted with epichlorohydrin;

[0076] Step A2: Mix Intermediate 2, phenothiazine and ethanol, stir and add dimethylaminoethyl acrylate at a stirring rate of 140 rpm and at a temperature of 65 °C, react for 24 h, carry out vacuum distillation, recrystallize with acetone / ethyl acetate, filter by suction, wash, and dry to obtain the cationic modifier;

[0077] The dosage ratio of intermediate 2, phenothiazine, ethanol and dimethylaminoethyl acrylate is 2.6 g: 0.008 g: 50 mL: 0.79 mL;

[0078] Figure 3 It is the 1H NMR spectrum of the cationic modifier for Example 3. From Figure 3 it can be seen that obvious characteristic peaks of carbon-carbon unsaturated double bonds appear at δ = 5.8 - 9.5, indicating that intermediate 2 has successfully reacted with dimethylaminoethyl acrylate to introduce unsaturated double bonds;

[0079] Step A3: Mix konjac glucomannan and deionized water, stir at a stirring rate of 140 rpm and a temperature of 40 °C for 15 min, then under nitrogen protection, stir and add ammonium cerium nitrate and the cationic modifier, react for 5 h, precipitate with acetone, filter, wash, and dry to obtain cationic konjac glucomannan;

[0080] The dosage ratio of konjac glucomannan, deionized water, ammonium cerium nitrate and the cationic modifier is 1.4 g: 130 mL: 0.045 g: 3.6 g;

[0081] The konjac glucomannan is from Guchen Biotech, and the product number is GC18123;

[0082] The magnetic polysilicate metal salt flocculant is prepared through the following steps:

[0083] Mix magnetic iron oxide particles, sodium metasilicate nonahydrate and deionized water, stir and add sulfuric acid solution and sodium hydroxide solution at a stirring rate of 140 rpm and a temperature of 40 °C, adjust the pH value to 3, stir for 3 h, age for 24 h, then add aluminum sulfate solution and sodium tetraborate solution, and stir at a stirring rate of 140 rpm and a temperature of 40 °C for 3 h to obtain the magnetic polysilicate metal salt flocculant;

[0084] The mass fraction of the sulfuric acid solution is 30%, the mass fraction of the sodium hydroxide solution is 15%, the molar concentration of the aluminum sulfate solution is 0.3 mol / L, the molar concentration of the sodium tetraborate solution is 0.15 mol / L, and the dosage ratio of magnetic iron oxide particles, sodium metasilicate nonahydrate, deionized water, aluminum sulfate solution and sodium tetraborate solution is 1.4 g: 15 g: 350 mL: 45 mL: 8 mL;

[0085] The magnetic iron oxide particles are magnetic iron oxide from Zhongke Yannuo, with a specification of 50 - 300 nm.

[0086] Comparative Example 1 Compared with Example 3, in this comparative example, the aluminum sulfate solution and sodium tetraborate solution in the preparation process of the magnetic polysilicate metal salt flocculant in Example 3 are removed, and other steps are the same.

[0087] Comparative Example 2 This comparative example is compared with Example 3. In the preparation process of the composite flocculant in Example 3, the cationic konjac glucomannan is replaced with konjac glucomannan, and other steps are the same.

[0088] Take the composite flocculants prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2. Mix 0.1 g of sodium humate, 0.5 g of kaolin and 10 L of deionized water, and adjust the pH value to 8 to prepare a water sample. Use a multi-parameter water quality detector to test and record the turbidity and chromaticity of the water sample. Add the composite flocculant to the water sample, and the dosage of the composite flocculant is 0.6 g / L. Under the conditions of a stirring rate of 180 rpm, a temperature of 30 °C, and visible light irradiation, stir for 5 min and settle for 10 min, then test its turbidity and chromaticity, and calculate its turbidity removal rate and chromaticity removal rate. Turbidity removal rate = (water sample turbidity - turbidity of the water sample after flocculation) / water sample turbidity * 100%, chromaticity removal rate = (water sample chromaticity - chromaticity of the water sample after flocculation) / water sample chromaticity * 100% to evaluate the flocculation performance of the composite flocculant. After the flocculation experiment, use a magnet to recover the composite flocculant for reuse, and at the same time use ultraviolet light irradiation, repeat the experiment 10 times, then test its turbidity and chromaticity again, and calculate its turbidity removal rate and chromaticity removal rate. The test results are shown in the following table:

[0089]

[0090] It can be seen from the test results in the shown table that when comparing Example 1, Example 2 and Example 3 with Comparative Example 1 and Comparative Example 2, in Comparative Example 1, the aluminum sulfate solution and sodium tetraborate solution in the preparation process of the magnetic polysilicate metal salt flocculant in Example 3 are removed. Due to the lack of doping of aluminum ions and boron ions, its flocculation performance decreases. In Comparative Example 2, the cationic konjac glucomannan in the preparation process of the composite flocculant in Example 3 is replaced with konjac glucomannan. Due to the lack of the introduction of azobenzene structure and quaternary ammonium structure, its flocculation performance and recycling and reuse performance decrease.

[0091] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0092] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of the present technology make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A preparation method of a composite flocculant containing a cationic etherifying agent, characterized in that: It includes the following steps: Step S1: Weigh the following raw materials in parts by weight: 15 - 20 parts of carboxymethyl guar gum, 12 - 15 parts of cationic konjac glucomannan, 1.2 - 1.5 parts of cationic etherifying agent, 1.8 - 2.2 parts of magnetic polysilicate metal salt flocculant, and 0.2 - 0.3 parts of preservative; Step S2: Mix the cationic konjac glucomannan, preservative, and magnetic polysilicate metal salt flocculant, stir at a temperature of 40°C for 15 - 20 min, then add carboxymethyl guar gum and cationic etherifying agent, raise the temperature to 50°C, continue stirring for 1.5 - 2 h, and cure for 12 h to obtain a composite flocculant containing cationic etherifying agent; The cationic konjac glucomannan is prepared through the following steps: Step A1: Mix azobenzene - 4 - benzoic acid, 3 - dimethylaminopropylamine, and tetrahydrofuran, stir and add N,N'-dicyclohexylcarbodiimide and 1 - hydroxybenzotriazole at a stirring rate of 160 - 180 rpm under room - temperature conditions, react for 20 - 24 h, perform vacuum distillation, recrystallize with acetone, filter by suction, wash, and dry to obtain Intermediate 1. Mix Intermediate 1, hydrochloric acid solution, and ethanol, stir and add epichlorohydrin at a stirring rate of 160 - 180 rpm under room - temperature conditions, stir for 10 - 15 min, raise the temperature to 60 - 65°C, react for 2 - 2.5 h, perform vacuum distillation, recrystallize with acetone, filter by suction, wash, and dry to obtain Intermediate 2; Step A2: Mix Intermediate 2, phenothiazine, and ethanol, stir and add dimethylaminoethyl acrylate at a stirring rate of 120 - 140 rpm under the condition of a temperature of 60 - 65°C, react for 20 - 24 h, perform vacuum distillation, recrystallize with acetone / ethyl acetate, filter by suction, wash, and dry to obtain a cationic modifier; Step A3: Mix konjac glucomannan and deionized water, stir at a stirring rate of 120 - 140 rpm under the condition of a temperature of 40°C for 10 - 15 min, then stir and add ammonium cerium nitrate and cationic modifier under nitrogen protection, react for 4 - 5 h, precipitate with acetone, filter by suction, wash, and dry to obtain cationic konjac glucomannan; The magnetic polysilicate metal salt flocculant is prepared through the following steps: Mix magnetic iron oxide particles, sodium metasilicate nonahydrate, and deionized water, stir and add sulfuric acid solution and sodium hydroxide solution at a stirring rate of 120 - 140 rpm under the condition of a temperature of 40°C, adjust the pH value to 3, stir for 2 - 3 h, cure for 24 h, then add aluminum sulfate solution and sodium tetraborate solution, and stir at a stirring rate of 120 - 140 rpm under the condition of a temperature of 40°C for 2 - 3 h to obtain magnetic polysilicate metal salt flocculant.

2. The preparation method of a composite flocculant containing a cationic etherifying agent according to claim 1, characterized in that: In Step A1: The dosage ratio of azobenzene - 4 - benzoic acid, 3 - dimethylaminopropylamine, tetrahydrofuran, N,N'-dicyclohexylcarbodiimide, and 1 - hydroxybenzotriazole is 1.1 - 1.15 g: 0.45 - 0.48 g: 25 - 30 mL: 0.95 - 0.98 g: 0.62 - 0.65 g; The mass fraction of the hydrochloric acid solution is 35%, and the dosage ratio of intermediate 1, hydrochloric acid solution, ethanol and epichlorohydrin is 2.4 - 2.6 g : 5 - 8 mL : 35 - 40 mL : 3.8 - 4.1 mL.

3. The preparation method of a composite flocculant containing a cationic etherifying agent according to claim 1, characterized in that: In step A2: The dosage ratio of intermediate 2, phenothiazine, ethanol and dimethylaminoethyl acrylate is 2.5 - 2.6 g : 0.006 - 0.008 g : 45 - 50 mL : 0.78 - 0.79 mL.

4. The preparation method of a composite flocculant containing a cationic etherifying agent according to claim 1, characterized in that: In step A3: The dosage ratio of konjac glucomannan, deionized water, ammonium cerium nitrate and cationic modifier is 1.2 - 1.4 g : 120 - 130 mL : 0.042 - 0.045 g : 3.4 - 3.6 g.

5. The preparation method of a composite flocculant containing a cationic etherifying agent according to claim 1, characterized in that: During the preparation of magnetic polysilicate metal salt flocculant: The mass fraction of the sulfuric acid solution is 30%, the mass fraction of the sodium hydroxide solution is 15%, the molar concentration of the aluminum sulfate solution is 0.3 mol / L, the molar concentration of the sodium tetraborate solution is 0.15 mol / L, and the dosage ratio of magnetic iron oxide particles, sodium metasilicate nonahydrate, deionized water, aluminum sulfate solution and sodium tetraborate solution is 1.2 - 1.4 g : 14 - 15 g : 300 - 350 mL : 40 - 45 mL : 5 - 8 mL.

6. A composite flocculant containing a cationic etherifying agent, characterized in that: Prepared by the preparation method according to any one of claims 1 - 5.

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