Detoxification of Arsenite through Adsorption and Oxidative Transformation on Pyrolusite

作者：Liu Chengshuai; Wang Xiangqing; Li Xiujuan; Cao Weidong^*; Yang Jinyan

来源：Clean-Soil Air Water, 2012, 40(11): 1265-1272.

DOI：10.1002/clen.201200027

• Manganese oxide
• Oxidation
• Toxicity
• Water treatment

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 Ca2+, Ni2+, and Mn2+, also decreased the detoxification rate of As(III). However, the trivalent ion Cr3+ largely increased the detoxification rate through co-precipitation and adsorption processes.

• 出版日期2012-11
• 单位青海大学; 中国农业科学院农业资源与农业区划研究所