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Preparation method of grafting amphoteric chitosan flocculant

A technology of chitosan and flocculant, which is applied in the field of preparation of grafted amphoteric chitosan flocculant, can solve the problems that the flocculation effect is sensitive to pH, inactive chemical properties, low molecular weight, etc., and achieves wide application range and enhanced Adhesive bridging flocculation, effect of increasing molecular weight

Inactive Publication Date: 2010-11-10
NANJING UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, chitosan also has many shortcomings in practical applications, such as: inactive chemical properties, poor solubility, relatively low molecular weight, and the flocculation effect is sensitive to pH, etc.

Method used

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  • Preparation method of grafting amphoteric chitosan flocculant
  • Preparation method of grafting amphoteric chitosan flocculant
  • Preparation method of grafting amphoteric chitosan flocculant

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Disperse chitosan in 20% sodium hydroxide aqueous solution, and basify at 50°C for 1 hour; then, add chloroacetic acid, the mass ratio of chloroacetic acid and chitosan is 3:2, react at 50°C for 4 hours; filter after the reaction is completed , to obtain carboxymethyl chitosan, carboxymethyl chitosan is dissolved in 1% hydrochloric acid solution, the mass percentage concentration that is mixed with carboxymethyl chitosan is 2% solution, after the solution is uniform, add cerium nitrate Ammonium was used as an initiator (the addition amount was 3% of the molar number of chitosan units), and then acrylamide was added (with carboxymethyl chitosan mass ratio: 5: 1), reacted for 2 hours at 45 ° C, and then reacted with acetone As a precipitating agent, the separated product can be precipitated to obtain the grafted amphoteric chitosan flocculant. According to nuclear magnetic analysis, the degree of substitution of carboxylic acid groups is 40%, and the content of polyacryla...

Embodiment 2

[0035] Disperse chitosan in 40% sodium hydroxide aqueous solution, alkalinize at 20°C for 0.5h; then, add chloroacetic acid, the mass ratio of chloroacetic acid to chitosan is 0.1:1, and react at 70°C for 10h; after the reaction is completed Filter to obtain carboxymethyl chitosan, dissolve the filtered carboxymethyl chitosan in 0.1% hydrochloric acid solution, and prepare a solution with a mass percentage concentration of carboxymethyl chitosan of 1%. After the solution is uniform, add Ammonium persulfate was used as an initiator (addition amount was 1% of chitosan unit moles), then added acrylamide (with carboxymethyl chitosan mass ratio: 1: 1), reacted for 1 hour at 65 ° C, and then Using acetone as a precipitating agent, the product was precipitated and separated to obtain a grafted amphoteric chitosan flocculant. According to nuclear magnetic analysis, the degree of substitution of carboxylic acid groups is 5%, and the content of polyacrylamide is 40% by mass. Solubility...

Embodiment 3

[0037] Disperse chitosan in 1% sodium hydroxide aqueous solution, alkalinize at 70°C for 3h; then, add chloroacetic acid, the mass ratio of chloroacetic acid and chitosan is 5:1, react at 70°C for 0.5h; after the reaction is completed Filter to obtain carboxymethyl chitosan, carboxymethyl chitosan is dissolved in 0.5% hydrochloric acid solution, the mass percent concentration that is mixed with carboxymethyl chitosan is 2% solution, after the solution is uniform, add nitric acid Cerium ammonium is used as initiator (addition amount is 1% of chitosan unit mole number), then adds acrylamide (with carboxymethyl chitosan mass ratio: 8: 1), reacts at 50 ℃ for 4 hours, then with Acetone is used as a precipitating agent to precipitate and separate the product, and the grafted amphoteric chitosan flocculant is obtained. According to nuclear magnetic analysis, the degree of substitution of carboxylic acid groups is 86%, and the content of polyacrylamide is 78% (by mass). Solubility ex...

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Abstract

The invention relates to a preparation method of a grafting amphoteric chitosan flocculant, comprising the following steps: carrying out graft copolymerization between carboxymethyl chitosan and polyacrylamide to obtain the grafting amphoteric chitosan flocculant, wherein the substituted ratio of a carboxyl group is 5%-90%, and the mass of the polyacrylamide is 40%-80% of the grafting amphoteric chitosan flocculant. The carboxymethyl chitosan can be obtained by separation after carboxylation reaction between chitosan and chloroacetic acid. The chitosan can adopt various commercially available products, and preferably, molecular weight of the chitosan is not less than 50,000, more preferably 750,000-850,000. The carboxymethyl chitosan grafting polyacrylamide flocculant prepared by the method of the invention improves water solubility of the chitosan, is applicable to treating water with different electric charges, and has good salt tolerance; and the flocculant can be also widely applied to an acid medium and an alkaline medium, and has wide adaptability to the pH value range.

Description

technical field [0001] The invention relates to a preparation method of a grafted amphoteric chitosan flocculant. Background technique [0002] In recent years, with rapid economic development and rapid industrial development, water pollution has become increasingly serious; and water is a basic need for human survival. The safety and security of drinking water has already attracted great attention from the country. On July 1, 2007, the newly revised "Drinking Water Sanitation Standard" (GB 5749-2006) was officially implemented, ending the 21-year old standard (GB 5749-1985). The indicators stipulated in the new standard have been greatly increased from the original 35 to 106, and the limits of some indicators are also stricter. In addition, on June 25, 2008, the state issued 11 new and more stringent industry emission standards including pulp and paper, electroplating, and fermentation. This has important practical significance for ensuring people's drinking water health...

Claims

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Application Information

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IPC IPC(8): C08F251/00C08F220/56C08B37/08C02F1/56
Inventor 杨琥尚亚波杨朕陈爱民卢耀柏蒋玉祥张文轩顾炜程镕时钱晓志
Owner NANJING UNIV
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