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Ping Hu and Jingtang Zheng
China University of Petroleum, China
Posters-Accepted Abstracts: J Chromatogr Sep Tech
Roxarsone (ROX) is heavily utilized in agricultural applications and poses a risk to the environment. The applicability of glow discharge plasma (GDP) for simultaneous oxidation of organo-arsenic and immobilization of arsenic is unprecedentedly evaluated in this study. The results show that ROX can be effectively oxidized to inorganic arsenic and this performance is evidently dependent on energy input. Adding Fe(II) significantly enhances the oxidation of ROX mainly because of the additional production of â�?¢OH via Fenton reaction in GDP, accompanied with which the generated arsenic can be immobilized in one process. Arsenic immobilization can be favorably obtained at pH 4.0-6.0 and Fe(II) concentration from 500 to 1000 mM. Based on the mineral compositions and the analysis (XRD/FTIR/XPS) of precipitate, a mechanism can be proposed that the oxidation of Fe(II) by H2O2 generated in situ in GDP significantly accelerates ROX transformation to the ionic As(V), which can immediately co-precipitate with Fe(III) ions or be adsorbed on the ferric oxyhydroxides, forming amorphous ferric arsenate-bearing ferric oxyhydroxides. Consequently, the Fenton enhanced GDP process exhibits as an economical and versatile strategy for organo-arsenic oxidation and arsenic immobilization, holding a premise for the remediation of organic arsenic wastewater.