Immobilization of selenium oxyanions from water resources is a helpful strategy to mitigate exposure to Se at concentrations toxic to human and ecosystem health. Pyroaurite-type minerals are layered double hydroxides with high anion exchange capacity with relevance in subsurface environments and applicable to water treatment technologies. Three types of Mg(II)-Fe(III) pyroaurites and Fe(II)-Fe(III) green rusts were evaluated in kinetic studies to determine the influence of different interlayer anions on the uptake of dissolved selenate (SeO₄²⁻) and selenite (HSeO₃⁻, SeO₃²⁻). Selenate and selenite uptake extents with pyroaurites were controlled by the identity of the interlayer anion according to the order Cl⁻> SO₄²⁻> CO₃²⁻, as predicted by known interlayer anion preferences for LDH. The kinetics of Se uptake typically expressed a rapid initial anion exchange step followed by a slow re-exchange back to solution due to competition with expelled interlayer anions. Excess dissolved interlayer anions and high pH values exacerbated this reverse exchange of Se. The results suggest Se oxyanions taken up by pyroaurites may not be firmly sequestered. Selenate uptake by redox-active green rust appears to be subject to the same interlayer anion preference as non-redox active pyroaurite, suggesting that the ability of green rust to reduce selenium oxyanions may be limited by the anion exchange process.

固定水资源中的硒氧阴离子是一种有用的策略，可减轻对人体和生态系统健康有毒浓度的硒的暴露。黄铁矿型矿物是具有高阴离子交换能力的层状双氢氧化物，与地下环境有关，适用于水处理技术。在动力学研究中评估了三种类型的Mg（II）-Fe（III）焦铁矿和Fe（II）-Fe（III）绿锈，以确定不同层间阴离子对溶解硒酸盐（SeO ₄ ^2-）吸收的影响。和亚硒酸盐（HSeO ₃ ^-，SEO ₃ ^2-）。吡咯铝酸盐对硒酸盐和亚硒酸盐的吸收程度由层间阴离子的身份按照Cl的顺序控制^- > SO ₄ ^2-- > CO ₃ ^2-，如通过LDH的已知层间阴离子偏好所预测的。硒吸收的动力学通常表现为快速的初始阴离子交换步骤，然后由于与排出的层间阴离子竞争而缓慢重新交换回溶液。过量的溶解层间阴离子和高pH值加剧了Se的这种反向交换。结果表明，吡咯铝酸盐吸收的Se氧阴离子可能没有被牢固地螯合。氧化还原活性绿锈对硒酸盐的吸收似乎与非氧化还原活性焦黄铁矿具有相同的层间阴离子偏好性，表明绿锈还原硒酸氧阴离子的能力可能受到阴离子交换过程的限制。