Water chemistry impacts on arsenic mobilization from arsenopyrite dissolution and secondary mineral precipitation: implications for managed aquifer recharge.
Water chemistry impacts on arsenic mobilization from arsenopyrite dissolution and secondary mineral precipitation: implications for managed aquifer recharge.
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DOI：
10.1021/es405119q
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发表时间：
2014-03
影响因子：
11.4
通讯作者：
C. Neil;Y. Je;rey Yang;D. Schupp;Young-Shin Jun
中科院分区：
文献类型：
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作者：
C. Neil;Y. Je;rey Yang;D. Schupp;Young-Shin Jun
管理含水层补给是一种水再利用技术，有可能满足日益增长的水需求。然而，MAR站点遇到了由于补给作业而引起的砷移动。为了应对这一挑战，必须确定MAR期间砷动员的机制。在这项实验室规模的研究中，对与MAR操作相关的条件下毒砂（FeAsS）中的砷动员进行了表征。实验测定的活化能为砷动员FeAsS在有氧条件下为36.9 ± 2.3 kJ/mol的10 mM氯化钠，40.8 ± 3.5 kJ/mol的10 mM硝酸钠，和43.6 ± 5.0 kJ/mol的二级出水从污水处理厂。有趣的是，氯化钠体系在有氧条件下显示出更高的砷动员。此外，次生矿物沉淀系统之间的变化，并进一步影响砷的动员。例如，废水系统抑制沉淀，而在氯化钠系统中，观察到氧化铁（III）（氢）沉淀物的更快相变，导致7天后形成赤铁矿。向赤铁矿的相变将导致用于砷衰减的可用表面积减少。这些新的观察和活化能可以是有用的，以开发改进的反应性运输模型的砷在MAR的命运，并制定战略，以尽量减少砷的释放。
Managed aquifer recharge (MAR) is a water reuse technique with the potential to meet growing water demands. However, MAR sites have encountered arsenic mobilization resulting from recharge operations. To combat this challenge, it is imperative to identify the mechanisms of arsenic mobilization during MAR. In this bench-scale study, arsenic mobilization from arsenopyrite (FeAsS) was characterized for conditions relevant to MAR operations. Experimentally determined activation energies for arsenic mobilization from FeAsS under aerobic conditions were 36.9 ± 2.3 kJ/mol for 10 mM sodium chloride, 40.8 ± 3.5 kJ/mol for 10 mM sodium nitrate, and 43.6 ± 5.0 kJ/mol for secondary effluent from a wastewater treatment plant. Interestingly, the sodium chloride system showed higher arsenic mobilization under aerobic conditions. In addition, secondary mineral precipitation varied among systems and further affected arsenic mobilization. For example, the wastewater system inhibited precipitation, while in the sodium chloride system, faster phase transformation of iron(III) (hydr)oxide precipitates was observed, resulting in hematite formation after 7 days. The phase transformation to hematite will result in less available surface area for arsenic attenuation. These new observations and activation energies can be useful to develop improved reactive transport models for the fate of arsenic during MAR, and develop strategies to minimize arsenic release.