Chinese Journal of Applied Chemistry ›› 2020, Vol. 37 ›› Issue (6): 673-682.DOI: 10.11944/j.issn.1000-0518.2020.06.190325

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Main Influencing Factors and Removal Mechanism of Phosphate Anions by Chitosan-Fe(III) Composite Gel Beads

ZHAO Bingbinga,DENG Dongyangb,CHEN Guihuab,SONG Qingmeib,FU Jianpingb,ZHANG Sukunb,ZHOU Chengyongac*(),JÜ Yongmingb   

  1. aSchool of Chemistry and Material Science,Shanxi Normal University,Linfen,Shanxi 041000,China
    bSouth China Institute of Environmental Sciences,Ministry of Ecology and Environment,Guangzhou 510655,China
    cChangzhi University,Changzhi,Shanxi 046000,China
  • Received:2019-11-29 Accepted:2020-04-17 Online:2020-06-01 Published:2020-06-08
  • Contact: ZHOU Chengyong
  • Supported by:
    Supported by the Guangdong International Cooperation Project(No.2018A050506045), the Guangdong Natural Science Foundation(No.2018A030313226), and the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515010969)

Abstract:

In order to improve the present situation of phosphorus pollution in environmental water, the chitosan iron (CS-Fe) composite gel beads were prepared by sol-titration-vacuum freeze drying method to remove phosphate from water. The morphology and structure of CS-Fe gel beads were characterized, and the factors affecting the adsorption of phosphate and the reaction mechanism were explored. The results show that the adsorption of phosphate by CS-Fe is a spontaneous, endothermic and entropy-increasing process, the adsorption process is in accordance with the pseudo first-order kinetic equation, the adsorption equilibrium time is 50 min, the maximum adsorption capacity calculated by Langmuir model is 23.97 mg/g, and the desorption efficiency is more than 90%. Fourier transform infrared (FT-IR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Zeta potential analysis and X-ray photoelectron spectroscopy show that CS-Fe forms a honeycomb structure which is favorable for the rapid adsorption of phosphate, and the adsorption mechanism includes electrostatic adsorption and ion exchange. The adsorbent combines the adsorption properties of metal compounds with the characteristics of chitosan macromolecule, which is conducive to the construction of porous materials and improvement of the adsorption effect. Gel beads materials are more conducive to recovery, avoid secondary pollution, and have potential applications.

Key words: chitosan gel beads, freeze-drying process, electrostatic adsorption, phosphate anions