Modified cyclodextrin - A good way to control environmental
With more and more attention paid to environmental protection, cyclodextrin has attracted more and more attention in wastewater treatment and environmental monitoring. Cyclodextrin has the unique structure of hydrophobic inner cavity, hydrophilic outer surface and superior physical and chemical properties. It can not only be used as the adsorption carrier of pollutants, but also has the characteristics of recyclable and degradable, which makes it show more and more broad application prospects in the treatment of environmental problems such as water pollution and pesticide pollutants.
Phenolic wastewater is from a wide range of sources, a large number of hazardous, and its toxic and hazardous wastes are the key projects to be solved in water pollution control. The hydrophobic cavity of cyclodextrin is matched with the molecular structure of phenol, and the adsorption of phenol can be included in the cavity, so as to realize the separation of waste water and cyclodextrin and reduce the content of phenol in waste water. In this process, cross-linking agents, such as epicloropropane, are often added, and -cyclodextrin polymer microspheres are prepared by reverse-phase emulsion polymerization. Spherical cyclodextrin polymer particles have better selective adsorption function for phenol.
Adsorbed heavy metal
Heavy metals are very difficult to degrade in nature, and they are enriched through the food chain, which greatly endangers human health. The common adsorbent has the characteristics of large specific surface area and electrostatic attraction. The addition of cyclodextrin can give the adsorbent stronger adsorption and retention ability due to its unique cavity structure. Cyclodextrin was modified by grafting polyacrylamide, and the water treatment agent prepared had 91% removal rate of chromium (Cr3+), and the -cyclodextrin/wood powder graft copolymer had the same removal rate of lead (Pb2+).
Degradation of pesticide pollutants
In the cultivation process of crops, it is inevitable to spray pesticides to reduce diseases, but the pollution caused by pesticides is also very obvious. The pesticide particles are floating in the air, landing on the water and falling into the soil, which will bring great damage to animals, humans and even the whole nature for a long time. Therefore, it is very necessary to accelerate the degradation of harmful substances in pesticides.
The degradation of pesticide pollutants is accelerated from three aspects: 1. Solubination of harmful substances; 2. 2. Elution of harmful substances; 3. Photodegradation of harmful substances. The hydrophobic cavity of cyclodextrin can be used to enclose the hydrophobic harmful substances (methyl parathion, pentachlorophenol, etc.), and then combined with the hydrophilic effect of the outer surface of cyclodextrin can achieve solubilization effect. In order to further improve the solubility, cyclodextrin is often modified. The solubilization of hydroxypropyl - -cyclodextrin is better than that of -cyclodextrin, and the photodegradation effect is also more significant. The triazine herbicide Atrazine is one of the most widely used herbicides with high persistence in the environment, and is one of the most commonly used indicators for the detection of soil and groundwater pesticides. The combination of humic acid and cyclodextrin in a certain proportion can effectively promote the photodegradation of Atrazine.
Purification of printing and dyeing wastewater
Dyes are widely used in textile, printing and dyeing, papermaking and other industries. Dye wastewater has high content of organic pollutants, complex components, difficult to biodegrade, photolysis and oxidation resistance, which has caused great pollution to the environment. For printing and dyeing wastewater pigment substances, cyclodextrin polymers can also play a better adsorption effect, so as to achieve the purification of printing and dyeing wastewater. Chitosan was bonded on -ring paste microsphere, which could effectively adsorb methyl orange solution. The compound gel of cyclodextrin/maleic acid and acrylic acid prepared by modification of maleic acid and acrylic acid can adsorb alkaline bonus extremely efficiently.
Treatment of other pollutants
The use of cyclodextrin to treat pollutants mainly relies on the inclusion of cyclodextrin hydrophobic cavities, and the modification of cross-linking agents and polymers to increase the adsorption performance, so that harmful substances can be "picked out" from the system and separated. According to different treatment requirements of pollutants, cyclodextrin modified by carboxymethyl cellulose was used to obtain hydrogels with great swelling properties. Some titanium dioxide can be used to achieve photochemical transformation of inorganic and organic pollutants, modified titanium dioxide with -cyclodextrin to improve the adsorption capacity of titanium dioxide, titanium dioxide selective photodegradation.
▲ Aqueous phase synthesis of swelling porous cyclodextrin polymer for the removal of organic micropollutants in water
The structural characteristics of cyclodextrin, "hydrophilic outside, hydrophobic inside", provide extensive space for its modification application. As an efficient and pollution-free carrier material, environmentally friendly modified cyclodextrin has made great contributions to the environmental protection in China. With the development of preparation, equipment and technology, modified cyclodextrin will serve human more effectively.
Qin B, Yang B. Study on the adsorption properties of acetylated -cyclodextrin polymer microspheres for alpha-naphthol [J]. Applied Chemical Industry, 2016(4): 3645-3653.
Zhang X J. Modification of -cyclodextrin and treatment of Chromium-containing wastewater [D]. Nanjing: Nanjing University of Aeronautics and Astronautics, 2014. (in Chinese)
 SiHongYan, li bin, Wang Ting, etc. Β - cyclodextrin/wood powder graft copolymer adsorption kinetics and thermodynamics of Pb2 + study [J]. Forest Products Chemistry and Industry, 2013(2): 1-9.
Tang C, Zeng Q R, Liao B H, et al. Different photolysis properties of -cyclodextrin and its derivatives for two pesticides [J]. (in Chinese with English abstract) Journal of Molecular Science, 2005(3): 52-57.
 Liu Shiyu, Xiang Wu, HUANG Bijie, et al. Effects of humic acid and -cyclodextrin on photodegradation of Atrazine [J]. Environmental Science and Technology, 2017(7) 93-96.
 Wang Hao, LIU Sen. Adsorption of basic Tibetan safflower dye by cyclodextrin/maleic acid-Acrylic complex gel [J]. Science, Technology and Engineering, 2019, 19(2): 256-261.
 Wang Rujun. Preparation of carboxymethyl cellulose / -cyclodextrin hydrogel and Its Application in industrial Wastewater Treatment [D]. Guangzhou: South China University of Technology, 2013.
Guo Li. Study on the adsorption and photocatalytic performance of -cyclodextrin modified nanometer titanium dioxide [D]. Wuhan: Wuhan University, 2011.
Yunfu Lixin Technology Co., LTD., formerly known as Yunnan Yongauroid Dextrin Co., LTD., was founded in 1987, focusing on the research and production of cyclodextrin and the development and innovation of related products. It is currently one of the largest specialized manufacturers in China. At present, Yunfu Li Innovation Technology Co., Ltd. is located in Shangcun Section of Buwu Village Committee, Hekou Sub-district, Yuncheng District, Yunfu City (Health and Medicine Industry Park, Yunfu City), with a land area of more than 13,000 square meters.