Arsenic in alkaline wastewater often takes place from gold mining process and creates a major problem to ecosystems and human health. In alkaline condition for arsenic removal, the application of adsorbent with a high positive surface charge is necessary. The current study is focused on the synthesis and characterization of an eco-friendly FeAl₁₂-polyoxocations intercalated nano-bentonite with a high positive surface charge for As(V) removal. Therefore, this pillared nano-bentonite was synthesized in different concentrations of clay suspension through a novel combination of the ultrasonic and microwave devices in one-step with decreasing water and time consumption. The characterization results showed that the incorporation of Al³⁺ and Fe³⁺ in pillared nano-bentonites increased the pH of zero point charge (pH_ZPC), d001 value, specific surface area, and micropore volume for arsenic removal. Various conditions such as the effect of coexisting anions and cations, arsenic concentration, adsorbent dosage, and contact time were investigated in the adsorption experiments. FeAl₁₂-pillared samples represented the maximum adsorption capacity of 121.3 mg L⁻¹ to remove 10–500 mg L⁻¹ of As(V). The adsorbability of products was also evaluated by using the two, three, and four parameters adsorption isotherms. The presence of a heterogeneous surface with more active sites under endothermic reaction played an important role for immobilization of As(V) with ligand exchange reaction. In the regeneration study, the high removal efficiency of arsenic (more than 87%) was found even after four cycles.

中文翻译：

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FeAl 12-多氧合插层法制备的悬浮液中的纳米膨润土插层制备，采用一步超声波-微波辐射从碱性废水中去除砷

碱性废水中的砷通常来自金矿开采过程，并给生态系统和人类健康带来重大问题。在碱性条件下去除砷时，必须使用具有高正表面电荷的吸附剂。目前的研究集中在具有高正表面电荷去除率As（V）的生态友好型FeAl _12-多氧插层纳米膨润土的合成与表征。因此，通过超声和​​微波装置的新颖组合，一步一步地在减少水和时间消耗的情况下，以不同浓度的粘土悬浮液合成了这种带柱状的纳米膨润土。表征结果表明，Al ³⁺和Fe ^3+的结合柱状纳米膨润土中的_γ可以增加零点电荷的pH（pH _ZPC），d001值，比表面积和用于除砷的微孔体积。在吸附实验中研究了各种条件，例如共存阴离子和阳离子的影响，砷浓度，吸附剂量和接触时间。FeAl ₁₂桩样品的最大吸附容量为121.3 mg L ^-1，可去除10–500 mg L ^-1的As（V）。还通过使用两个，三个和四个参数吸附等温线来评估产物的吸附性。在吸热反应下具有更多活性位点的异质表面的存在对于通过配体交换反应固定As（V）发挥了重要作用。在再生研究中，即使经过四个循环，也发现了很高的除砷效率（超过87％）。