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| Stabilization treatment of available arsenic in contaminated soils and mechanism studies |
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Abstract Lime and Ferrous salt was used as the auxiliary agent and stabilizing agent to treat two arsenic contaminated soils. Following chemical leaching test, the stabilizing effectiveness and mechanism of available arsenic on treated soil were shown using morphology and structure analysis. Importantly, the stabilizing efficiency of arsenic for the two types of soils were both over 85% when the ratio of exogenous Fe and soil As (mol/mol) was 6:1~8:1 and the dosing ratio of CaO was 0.05% ~ 0.1% (w/w). The stabilization of arsenic in soil was attributed mainly to two following reasons: (1) arsenic was transformed from non-specific adsorption and the specific adsorption state into the weakly crystalline Fe-Al or Fe-Mn hydrated oxides and (2) crystalline Fe-Al or Fe-Mn hydrated oxides state. The new phase of hydroxyl arsenic copper mineral (As2Cu5H4O12) was generated after the stabilization treatment of the contaminated soils.
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Received: 23 May 2012
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