title: Preparation of cationic starch microspheres and study on their absorption to anionic-type substance.
abstract: Cationic starch microspheres (CSMs) were prepared from lab-made neutral starch-based microspheres using a cationic adsorbent, namely 3-chloro-2-hydroxypropyltrimethyl ammonium chloride, as the cationic etherifying agent. Detection by scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and laser diffraction techniques revealed that CSMs had coarse surfaces with good sphericity and dispersibility. Differential thermal analysis showed the lower thermostability of the CSMs' main chains. Furthermore, scores of experiments confirmed that CSMs are capable of absorption to N-(phosphonomethyl) iminodiacetic acid (PMIDA), a type of anionic substance, which is the intermediate to the preparation of glyphosate, maximally up to 95.24 mg/g. Compared with the Freundlich isotherm model, the Langmuir isotherm model can better describe the absorption process. The kinetic study showed that the pseudo-second-order model demonstrated a better correlation of the experimental data in contrast with the pseudo-first-order model. It can be therefore concluded that the rate-limiting step was the chemical absorption rather than the mass transport.
authors.affiliation: Chongqing University, China E-mail: zhengjie@cqu.edu.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Chongqing University, China E-mail: zhengjie@cqu.edu.cn.
authors.forename: YaNan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Xingjiang Agricultural University, China.
authors.forename: ZuoShan
authors.initials: Z
authors.lastname: Feng
authors.affiliation: Chongqing University, China E-mail: zhengjie@cqu.edu.cn.
authors.forename: ZeMin
authors.initials: Z
authors.lastname: Kuang
authors.affiliation: Chongqing University, China E-mail: zhengjie@cqu.edu.cn.
authors.forename: DeZhou
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Chongqing University, China E-mail: zhengjie@cqu.edu.cn.
authors.forename: XueMin
authors.initials: X
authors.lastname: Jiao
mesh_terms: D000327:Adsorption; D000838:Anions / Q000737:chemistry*; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry; D006540:Herbicides / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D017550:Spectroscopy, Fourier Transform Infrared; D013213:Starch / Q000737:chemistry*; D000097797:Glyphosate
chemical_list: D000838:Anions; D005998:Glycine; D006540:Herbicides; D013213:Starch; D000097797:Glyphosate