School of Water Resources, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
Sci Rep. 2020 Mar 18;10(1):4982. doi: 10.1038/s41598-020-61763-z.
Polyaniline hollow microsphere (PNHM)/FeO magnetic nanocomposites have been synthesized by a novel strategy and characterized. Subsequently, PNHM/FeO-40 (FeO content: 40 wt.%) was used as an adsorbent for the removal of arsenic (As) from the contaminated water. Our investigations showed 98-99% removal of As(III) and As(V) in the presence of PNHM/FeO-40 following pseudo-second-order kinetics (R > 0.97) and equilibrium isotherm data fitting well with Freundlich isotherm (R > 0.98). The maximum adsorption capacity of As(III) and As(V) correspond to 28.27 and 83.08 mg g, respectively. A probable adsorption mechanism based on X-ray photoelectron spectroscopy analysis was also proposed involving monodentate-mononuclear/bidentate-binuclear As-Fe complex formation via legend exchange. In contrast to NO and SO ions, the presence of PO and CO co-ions in contaminated water showed decrease in the adsorption capacity of As(III) due to the competitive adsorption. The regeneration and reusability studies of spent PNHM/FeO-40 adsorbent showed ~83% of As(III) removal in the third adsorption cycle. PNHM/FeO-40 was also found to be very effective in the removal of arsenic (<10 μg L) from naturally arsenic-contaminated groundwater sample.
聚苯胺中空微球（PNHM）/FeO 磁性纳米复合材料已通过一种新策略合成，并进行了表征。随后，PNHM/FeO-40（FeO 含量：40wt%）被用作吸附剂，从受污染的水中去除砷（As）。我们的研究表明，在 PNHM/FeO-40 的存在下，As(III)和 As(V)的去除率达到 98-99%，符合准二级动力学（R>0.97）和平衡等温线数据拟合良好的 Freundlich 等温线（R>0.98）。As(III)和 As(V)的最大吸附容量分别对应为 28.27 和 83.08mg/g。还提出了一种基于 X 射线光电子能谱分析的可能吸附机制，涉及通过配位交换形成单核/双核 As-Fe 配合物的单齿-单核/双齿-双核。与 NO 和 SO 离子不同，受污染水中 PO 和 CO 共存离子的存在会由于竞争吸附而降低 As(III)的吸附容量。用过的 PNHM/FeO-40 吸附剂的再生和重复使用研究表明，在第三次吸附循环中，As(III)的去除率约为 83%。PNHM/FeO-40 也被发现非常有效地从天然含砷地下水样本中去除砷（<10μg/L）。
