Chem. J. Chinese Universities ›› 2023, Vol. 44 ›› Issue (2): 20220470.doi: 10.7503/cjcu20220470

• Physical Chemistry • Previous Articles     Next Articles

Modification Mechanism of Mannitol for Preparation of Highly Active Nano-zerovalent Iron

HE Yuting1, NIU Huibin2, ZHANG Zhaonian4, ZHANG Jing1, FU Guirong2, CHEN Chuncheng3, HUANG Yingping2, FANG Yanfen1,2()   

  1. 1.College of Materials and Chemical Engineering,China Three Gorges University,Yichang 443002,China
    2.Engineering Research Center of Eco?environment in Three Gorges Reservoir Region,Ministry of Education,China Three Gorges University,Yichang 443002,China
    3.Institute of Chemistry Chinese Academy of Sciences,Beijing 100190,China
    4.Hubei Provincial Department of Ecology and Environment Yichang Ecological Environment Monitoring Center,Yichang 443005,China
  • Received:2022-07-11 Online:2023-02-10 Published:2022-09-19
  • Contact: FANG Yanfen E-mail:chem_ctgu@126.com
  • Supported by:
    the National Natural Science Foundation of China(22136003);the Program of Introducing Talents of Discipline to Universities, China(D20015);the Three Gorges Reservoir Area Ecological Environment Education Ministry Engineering Research Center Open Fund, China(KF2022-03)

Abstract:

Nano zero-valent Iron(nZVI) has been widely used in water pollution treatment. The preparation method of nZVI with high purity and good dispersion has always been a research focus. In this paper, alcohols with different numbers of hydroxyl groups were used as modifiers, including ethanol, ethylene glycol, erythritol, mannitol and sorbitol, to prepare nZVI-EA, nZVI-EG, nZVI-ER, nZVI-M and nZVI-S sample, respectively. The above samples were applied to the reduction and removal of microcystin(Microcystin-LR, MC-LR) in water. The results showed that with the increase of hydroxyl groups, the antioxidant capacity and dispersity of modified nZVI were enhanced, and the degradation rate of MC-LR was also increased. The surface-area-normalized rate coefficient of nZVI-M(79.35×10-5 L·m‒2·min‒1) was 9.3 times that of nZVI-S(8.55×10-5 L·m‒2·min‒1) and 61.0 times that of nZVI0(unmodified sample, 1.30×10-5 L·m‒2·min‒1). It was found by X-ray diffraction(XRD), energy dispersive spectroscopy(EDS) and potassium dichromate titration that this may be due to the highest Fe0 purity of nZVI-M(total iron content is 83.5%). In order to reveal the modification mechanism, the preparation process of nZVI-M was observed by optical microscope. It was found that transparent rod-like mannitol crystal clusters formed on the surface of Fe0, which improved the antioxidant capacity and dispersion of nZVI in water, and realized the efficient degradation of MC-LR. Unlike the hydroxyl group of sorbitol, the hydroxyl group of mannitol has a “jagged” distribution and its O2p orbital is prone to electron delocalization to form strong coordination with Fe3+. This will provide a new way to obtain nZVI with high purity and good dispersion by the coordination of alcohol hydroxyl groups.

Key words: Nano zero-valent iron, Mannitol, Sorbitol, Modification, Removal

CLC Number: 

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