WO2021237378A1

WO2021237378A1 - Method for preparing cationic starch

Info

Publication number: WO2021237378A1
Application number: PCT/CN2020/091946
Authority: WO
Inventors: 覃华贤
Original assignee: 南通市多乾新材料科技有限公司
Priority date: 2020-05-23
Filing date: 2020-05-23
Publication date: 2021-12-02

Abstract

A method for preparing a cationic starch with the following steps: adding GTA into a NaOH solution at a concentration of 5.0 g/L, stirring for 15-25 min, then adding corn starch, water bathing at a condition of 64-68 °C for 35-45 min, cooling to room temperature, microwaving at a medium power level for 2-4 min, repeating for 6 times and each time cooling to room temperature after microwaving, using ethanol to rinse a crude product produced for 4-6 times, extracting a precipitation and vacuum drying at 55-65 °C for 7-9 h, and crushing via a 75 μm sieve, thus completing the process. The method is simple, quick, and easy to operate, the cationic starch prepared provides a great flocculation effect, and allows large-scale preparation.

Description

Method for preparing cationic starch

Technical field

The invention relates to a method for preparing cationic starch.

Background technique

With the acceleration of social industrialization, the eutrophication of lakes is becoming more and more serious. Algae obtain rich nutrition and multiply, which leads to the decline of water quality, the decline of functions, and the imbalance of the water ecosystem, making it an urgent worldwide problem. Physical, chemical, and biological algae control technologies have been extensively studied. Natural flocculants have become a research hotspot at home and abroad in recent years because of their raw materials safety, non-toxicity, and high efficiency. Cationic starch is an important starch ether derivative prepared by modified starch through the conversion of starch surface functional groups and graft copolymerization. It belongs to cationic modified starch. Among them, cationic starch with higher degree of substitution is mainly used in water treatment and Anion exchange and other aspects. Among the many natural modified polymer flocculants, the research and development of modified starch flocculants are particularly eye-catching. They have the advantages of non-toxicity, low price, easy biodegradation, wide sources of raw materials, and the formation of a virtuous cycle in nature. Research on cationic starch has been started very early abroad. In comparison, although cationic starch in my country has been used in the paper industry, textile industry, and wastewater treatment, it is still in the trial production stage. Cationic starch has a very good performance in my country. Development prospects.

At present, in the field of cyanobacteria flocculation, traditional flocculating agents such as aluminum chloride and ferric chloride often cause secondary pollution. The large dosage of modified clay has become a limiting factor for its wide application. Although there is a good flocculation effect under acidic conditions, when pH>7, the flocculation efficiency decreases linearly. However, the lake water is usually alkaline (pH is about 8 or even more than 9) when the cyanobacteria "bloom" erupts. At present, most of the articles on the flocculation of algae with natural inorganic polymer flocculants are mainly about the flocculation and harvesting of microalgae and the study of the flocculation of indoor purely cultivated algae species. However, there are few studies on the flocculation of cyanobacteria in the field. Therefore, cationic starch flocculants are studied. The flocculation of cyanobacteria in the wild and the control and removal of cyanobacteria "blooms" have important practical application value.

Summary of the invention

The purpose of the present invention is to provide a method for preparing cationic starch.

The present invention is realized through the following technical solutions:

A method for preparing cationic starch includes the following steps: adding 5-15 parts of GTA to 90-100 parts of NaOH solution with a concentration of 5.0g/L, stirring for 15-25 minutes, and then adding 15-25 parts of corn starch, In a water bath at 64-68°C for 35-45 minutes, cool to room temperature, microwave for 2-4 minutes on medium heat, repeat 6 times and cool to room temperature after each microwave. The obtained crude product is washed 4-6 times with ethanol, and the precipitate is collected at 55 Vacuum drying at -65°C for 7-9 hours, crushing through a 75μm sieve, and then obtaining; all raw materials are parts by weight.

Preferably, in the preparation method, stirring is performed for 20 minutes.

Preferably, in the preparation method, a water bath is carried out at 66° C. for 40 minutes.

Preferably, in the said preparation method, microwave for 3 minutes on medium heat.

Preferably, in the preparation method, the precipitate is taken and dried in vacuum at 60° C. for 8 hours.

The technical effect of the present invention:

The method is simple, fast and easy to operate, and the prepared cationic starch has good flocculation effect and can be prepared on a large scale.

Detailed ways

The substantive content of the present invention will be specifically introduced below in conjunction with the embodiments.

Example 1

A method for preparing cationic starch includes the following steps: adding 10 parts of GTA to 95 parts of NaOH solution with a concentration of 5.0g/L, stirring for 20 minutes, then adding 20 parts of corn starch, and cooling in a water bath at 66°C for 40 minutes. Bring to room temperature, microwave for 3 minutes on medium heat, repeat 6 times and cool to room temperature after each microwave, wash the obtained crude product with ethanol 5 times, take the precipitate and dry it in vacuum at 60°C for 8 hours, crush it through a 75μm sieve, and get it; It is parts by weight.

Example 2

A method for preparing cationic starch, including the following steps: adding 5 parts of GTA to 90 parts of NaOH solution with a concentration of 5.0g/L, stirring for 15 minutes, and then adding 15 parts of corn starch, in a water bath at 64°C for 35 minutes, and cooling Bring to room temperature, microwave for 2 minutes on medium heat, repeat 6 times and cool to room temperature after each microwave. Wash the obtained crude product with ethanol 4 times, take the precipitate and dry it in vacuum at 55°C for 7 hours, crush it through a 75μm sieve, and get it; It is parts by weight.

Example 3

A method for preparing cationic starch includes the following steps: adding 15 parts of GTA to 100 parts of NaOH solution with a concentration of 5.0g/L, stirring for 25 minutes, then adding 25 parts of corn starch, and cooling in a water bath at 68°C for 45 minutes. To room temperature, microwave on medium heat for 4 minutes, repeat 6 times and cool to room temperature after each microwave. Wash the obtained crude product with ethanol 6 times, take the precipitate and vacuum dry at 65°C for 9 hours, crush it through a 75μm sieve, and get it; It is parts by weight.

Claims

A method for preparing cationic starch, which is characterized in that it comprises the following steps: adding 5-15 parts of GTA to 90-100 parts of NaOH solution with a concentration of 5.0g/L, stirring for 15-25 minutes, and then adding 15-25 parts of corn Starch, in a water bath at 64-68°C for 35-45 minutes, cool to room temperature, microwave on medium heat for 2-4 minutes, repeat 6 times and cool to room temperature after each microwave, wash the obtained crude product with ethanol 4-6 times, and take The precipitate is vacuum dried at 55-65°C for 7-9h, and crushed through a 75μm sieve to obtain; each raw material is in parts by weight.
The preparation method according to claim 1, characterized in that: stirring for 20 minutes.
The preparation method according to claim 1, characterized in that: in a water bath at 66°C for 40 minutes.
The preparation method according to claim 1, characterized in that: microwave on medium heat for 3 minutes.
The preparation method according to claim 1, characterized in that: taking the precipitate and vacuum drying at 60°C for 8 hours.