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Detoxification of Arsenite through Adsorption and Oxidative Transformation on Pyrolusite
Author(s) -
Liu Chengshuai,
Wang Xiangqing,
Li Xiujuan,
Cao Weidong,
Yang Jinyan
Publication year - 2012
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201200027
Subject(s) - pyrolusite , chemistry , adsorption , arsenite , arsenic , detoxification (alternative medicine) , arsenate , inorganic chemistry , niclosamide , aqueous solution , organic chemistry , manganese , medicine , alternative medicine , pathology , ecology , biology
Adsorption and oxidative transformation processes critically affect the mobility and toxicity of arsenic (As) in the environment. In this study, the detoxification of arsenite through adsorption and oxidation by pyrolusite was systematically investigated. Disappearance of aqueous As(III) in the solution can be efficiently achieved using pyrolusite. The As(III) oxidative transformation product arsenate or As(V) was obtained both in the solution and on the pyrolusite surface. The arsenic species adsorbed on pyrolusite exist in two forms: As(III) and As(V). Furthermore, over 64.8% of the adsorbed As cannot be desorbed. They were fixed more stably in the structure of the mineral to achieve a safer removal. Lower As(III) initial concentration increased As(III) detoxification rates. Elevating the reaction pH from 4.5 to 7.9 elicited a slight effect on the disappearance rate of As(III). Efficient As(III) detoxification can be achieved by pryrolusite within the studied pH range. The addition of low‐molecular‐weight carboxylic acids decreased the detoxification rate of As(III) through competition for active sites on pyrolusite. Co‐existing divalent metal ions, such as Ca 2+ , Ni 2+ , and Mn 2+ , also decreased the detoxification rate of As(III). However, the trivalent ion Cr 3+ largely increased the detoxification rate through co‐precipitation and adsorption processes.