title: Controlled release and retarded leaching of pesticides by encapsulating in carboxymethyl chitosan /bentonite composite gel.
abstract: A novel composite gel composed of carboxymethyl-chitosan (CM-chit) and bentonite (H-bent) was used as the carrier for encapsulating atrazine and imidacloprid to control their release in water and retard their leaching in soil. Strong interactions between CM-chit and H-bent in the composite were confirmed by FT-IR, and good dispersion of pesticides in the carrier was observed by SEM. According to the results of release experiments in water, the CM-chit/H-bent composite carrier showed double advantages of both encapsulation by the polymer and sorption by the bentonite. The time taken for 50 % of active ingredients to be released, t₅₀, was prolonged to 572 h for atrazine and 24 h for imidacloprid, respectively. The difference between the two pesticides on release behavior was related to their hydrophobicity and water solubility. Leaching experiments through a soil layer showed that this novel carrier reduced the amount of pesticides available for leaching, and would be useful for diminishing the environmental pollution of pesticides.
authors.affiliation: Department of Chemistry, Shaoxing University, Zhejiang , China. ljf@usx.edu.cn
authors.forename: Jianfa
authors.initials: J
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Yao
authors.forename: Yimin
authors.initials: Y
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Shao
mesh_terms: D001546:Bentonite / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry* / Q000494:pharmacology; D004337:Drug Carriers / Q000737:chemistry*; D010575:Pesticides / Q000737:chemistry* / Q000494:pharmacology; D012987:Soil / Q000737:chemistry
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D010575:Pesticides; D012987:Soil; C514968:carboxymethyl-chitosan; D001546:Bentonite; D048271:Chitosan