Preparation And Application Of Magnetic Chitosan In Environment Analysis

Chitosan is the alkaline deacetylated product of chitin, which is derived from the exoskeleton of crustaceans. It is non-toxic, biocompatible, biodegradable and anti-bacterial. Chitosan have been widely used in many fields, such as pharmaceutical, chemical, food, biomedical engineering, etc. Magnetic materials can be separated or located quickly with an external magnetic field which can simplify the experiment process, save the operating time, and thus is a kind of superior performance vector. This study combined chitosan with the magnetic material via different methods to form magnetic chitosan and used them to separate and analyze several pollutants in the environment, including three kinds of pyrethroids, chlorpyrifos and malachite green. The main contents are listed as follow:(1) By coprecipitation method, Fe2+, Fe3+and chitosan were dissolved in the buffer solution, then precipitated by one step reaction in alkaline condition. The synthesized magnetic chitosan was characterized by SEM, FTIR and PPMS, and used to extract the pyrethroids in aqueous solution. The obtained linearity of beta-cyfluthrin, cyhalothrin and cyphenothrin was in the range of30-3000ng/L. The LOD were7.5,5.6and6.1ng/L, respectively. The LOQ of three pyrethroids were25.0,18.7and20.3ng/L, respectively. The intra-day and inter-day precisions of three pyrethroids were in the range of3.6-5.2%and5.9-8.6%, respectively.(2) Fe3O4was snythsized by coprecipitation method, and then crosslinked by chitosan with glutaraldehyde under the span-80paraffin mixed system. The synthesized magnetic chitosan by crosslinking method was characterized by TEM, FTIR and PPMS, and used to absorb the chlorpyrifos in the soil. The optimize conditions, such the mount of the adsorbent, extraction time and elute, were discussed.(3) Fe3O4was snythsized by hydrothermal method, and then crosslinked by carboxymethyl chitosan with glutaraldehyde. The magnetic carboxymethyl chitosan was characterized by TEM, FTIR and PPMS, and used to adsorption and separation the malachite green in aqueous solution. The adsorption characteristics of malachite green by magnetic carboxymethyl were studied, the adsorption kinetics and adsorption isotherm were discussed. In different pH value, the absorption efficiency were different and it was found that the adsorption capacity was94.97%of the initial adsorption capacity after being used five times desorbed by10%acetic acid methanol.