High-substituted quaternary ammonium polysaccharide bioflocculant and preparation method thereof

Abstract

The invention provides a high-substituted quaternary ammonium polysaccharide bioflocculant and a preparation method thereof. The preparation method comprises the following steps: alkalizing an aqueous solution of a raw material non-ionic bioflocculant in the presence of a certain amount of a catalyst at a certain water bath temperature through a wet process, slowly adding a certain amount of a dispersant in a dropwise manner, adding an etherifying agent, reacting for a period of time, precipitating, washing with water, washing with alcohol, drying, and grinding to prepare the quaternary ammonium polysaccharide bioflocculant with the substitution degree of 0.2-1.8. The method adopting the wet process has the advantages of good stability, simple operation, easy separation, high reaction conversion rate, high cost performance, and waste liquid recycling, and the quaternary ammonium polysaccharide bioflocculant has the advantages of non-toxicity, environmental protection, no secondary pollution and biodegradability, can be used for processing drinking water, printing and dyeing wastewater, coal washing water, mineral processing, oil refining wastewater, papermaking and chemical industry wastewater, and the like, and has substantial environmental and social benefits.

Description

technical field [0001] The invention belongs to the technical field of water treatment flocculants, in particular to a high-substitution quaternary ammonium polysaccharide biological flocculant and a preparation method thereof. Background technique [0002] Among the currently commonly used flocculants for water treatment, although polyaluminum, polyiron, and polyacrylamide have good flocculation effects, they cause metal residues, large amounts of sludge, corroded pipelines, and polyacrylamide in water bodies. Many problems such as the monomer residue in the compound have aroused widespread attention at home and abroad. Since the 1970s, countries such as the United States, Japan, Britain, and India have carried out the research and development of chemically modified natural organic polymer materials, among which bioflocculants containing polysaccharides, proteins, glycoproteins or cellulose are natural polymers. Materials, produced by microbial metabolism, have good floccu...

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Problems solved by technology

Take modified starch as an example: the invention patent with the patent number 200610166835.X discloses a high degree of substitution quaternary ammonium cationic starch flocculant and its synthesis method, and the invention patent with the notification number CN1352196A discloses a semi-dry method for preparing In the process of quaternary ammonium cationic starch, the degree of substitution of etherified starch used in industry is generally lower than 0.2. Although cationic starch ether with high degree of substitution has good performance, it is difficult to prepare, the reaction efficiency is low, and the cost is high. For example, Thomas Heinze prepared a cationic starch ether with a degree of substitution of 1.05, and the reaction efficiency was only 52%. When the molar ratio of cationic starch and etherifying agent was selected to be 1:10 during the secondary etherification, the degree of substitution was as high as 1.5, but the reaction efficiency The maximum is only 10%. In addition to the preparation process factors, the generated cationic starch with low substitution degree is also positively charged due to steric hindrance, which also inhibits its further substitution.

[0004] Etherification modification mainly adopts dry method and wet method. Although the dry method has the advantages of no three wastes, simple process, and short reaction cycle, but the reaction conversion rate is low, the requirements for equipment are high, and the product quality is unstable. Only a few manufacturers adopt this method. Wet method is the main method currently adopted, and it is also the earliest method adopted, which can obtain products with higher conversion rate, high reaction efficiency, low equipment requirements, and simple process, but there are three wastes, post-washing and drying equipment that cost a lot difficult to deal with

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