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摘要
Despite the environmental risks arising from antimony-contaminated sites, critical factors controlling the mobility of Sb in soils have still not been fully identified to date. We performed column experiments to investigate how reducing conditions affect Sb leaching from a calcareous shooting range soil, with a special focus on the relationship between Sb release and mineral dissolution processes. After eluting the columns for 5 days with 15mM lactate solution at a flow rate of 33 mm day(-1), the flow was interrupted for 37 days and then resumed for another 5 days. With the transition to moderately reducing conditions (similar to 300 mV) after 1 day of flow, effluent Sb-V and manganese (Mn) concentrations showed a concomitant increase, providing evidence that Sb-V associated to these phases was released by the reductive dissolution of Mn minerals. The release of Sb-V was counteracted by the reduction to Sb-III, which was first scavenged by iron (Fe) (hydr) oxides and then slowly liberated again when the redox potential further decreased to Fe-reducing conditions. Laser ablation-inductively coupled plasma-mass spectrometry revealed the presence of an initial pool of Sb associated with Mn-containing, Fe-free phases, underpinning the important role of the latter in addition to Fe (hydr)oxides as Sb sorbents.
- 出版日期2014
