Mobilisation of arsenic from bauxite residue (red mud) affected soils: Effect of pH and redox conditions
Mobilisation of arsenic from bauxite residue (red mud) affected soils: Effect of pH and redox conditions
复制标题
DOI：
10.1016/j.apgeochem.2014.10.009
复制
发表时间：
2014-12-01
影响因子：
3.4
通讯作者：
Burke, Ian T.
中科院分区：
文献类型：
--
作者：
Lockwood, Cindy L.;Mortimer, Robert J. G.;Burke, Ian T.
2010年，匈牙利西部阿伊卡氧化铝厂的尾矿坝决口，向周边地区排放了约100万立方米的赤泥悬浮液。红泥（细粒铝土矿残渣）具有典型的碱性pH值，并含有几种潜在的有毒元素，包括砷。利用阿伊卡附近的土壤进行了好氧和厌氧批次实验，以研究赤泥添加对受赤泥泄漏影响的土地的土壤-水实验中土壤地球化学和砷移动性的影响。XAS分析表明，砷以砷酸盐的形式存在于赤泥中。赤泥关联的砷酸盐的再活化是高度依赖于pH值和磷酸盐的添加到赤泥悬浮液大大提高了作为释放到溶液中。在好氧批实验中，其中赤泥与土壤混合，作为释放到溶液中是高度依赖于pH值。碳酸化这些碱性溶液的溶解大气中的CO2降低pH值，这导致随着时间的推移，在水溶液中的As浓度下降。然而，这并没有导致在任何实验中完全去除含水As。在厌氧实验中没有发生碳酸化，pH值仍然很高。在所有的厌氧赤泥改良实验中，水溶液As浓度最初增加，然后随着系统变得更加还原而保持相对恒定，XANES和HPLC-ICP-MS都表明没有发生As还原过程，并且仅存在As（V）物种。这些实验表明，在好氧和厌氧条件下，在土壤-水系统的影响下，赤泥除了有可能增加作为流动性。(C)2014作者爱思唯尔有限公司出版
The tailings dam breach at the Ajka alumina plant, western Hungary in 2010 introduced similar to 1 million m(3) of red mud suspension into the surrounding area. Red mud (fine fraction bauxite residue) has a characteristically alkaline pH and contains several potentially toxic elements, including arsenic. Aerobic and anaerobic batch experiments were prepared using soils from near Ajka in order to investigate the effects of red mud addition on soil biogeochemistry and arsenic mobility in soil-water experiments representative of land affected by the red mud spill. XAS analysis showed that As was present in the red mud as As(V) in the form of arsenate. The remobilisation of red mud associated arsenate was highly pH dependent and the addition of phosphate to red mud suspensions greatly enhanced As release to solution. In aerobic batch experiments, where red mud was mixed with soils, As release to solution was highly dependent on pH. Carbonation of these alkaline solutions by dissolution of atmospheric CO2 reduced pH, which resulted in a decrease of aqueous As concentrations over time. However, this did not result in complete removal of aqueous As in any of the experiments. Carbonation did not occur in anaerobic experiments and pH remained high. Aqueous As concentrations initially increased in all the anaerobic red mud amended experiments, and then remained relatively constant as the systems became more reducing, both XANES and HPLC-ICP-MS showed that no As reduction processes occurred and that only As(V) species were present. These experiments show that there is the potential for increased As mobility in soil-water systems affected by red mud addition under both aerobic and anaerobic conditions. (C) 2014 The Authors. Published by Elsevier Ltd.