Department of Civil and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260, Singapore; Shanghai Emperor of Cleaning Hi-tech Limited Company, 1230 North Zhongshan Road, Shanghai, 200437, China.
Department of Civil and Environmental Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore, 119260, Singapore; NUS Environmental Research Institute, National University of Singapore, 5A Engineering Drive 1, #02-01, Singapore, 117411, Singapore.
Chemosphere. 2022 Feb;288(Pt 3):132634. doi: 10.1016/j.chemosphere.2021.132634. Epub 2021 Oct 23.
Arsenic is a highly toxic pollutant and exists in inorganic and organic forms in groundwater and industrial wastewater. It is of great importance to reduce the arsenic content to lower levels in the water (e.g., <10 ppb for drinking) in order to minimize risk to humans. In this study, a Fe-Mn-Zr ternary magnetic sorbent was fabricated via precipitation for removal of inorganic and organic arsenate. The synthesis of sorbent was optimized by Taguchi method, which leads to an adsorbent with higher adsorption capacity. The adsorption of As(V) was pH dependent; the optimal removal was achieved at pH 2 and 5 for inorganic and organic As(V), respectively. Contact time of 25 h was sufficient for complete adsorption of both inorganic and organic As(V). The adsorption isotherm study revealed that the adsorbent performed better in sequestration of inorganic As(V) than that of organic As(V); both adsorption followed the Langmuir isotherm with maximum adsorption capacities of 81.3 and 16.98 mg g for inorganic and organic As(V), respectively. The existence of anions in the water had more profound effect on the adsorption of organic As(V) than the inorganic As(V). The co-existing silicate and phosphate ions caused significantly negative impacts on the adsorption of both As(V). Furthermore, the existence of humic acid caused the deterioration of inorganic As(V) removal but showed insignificant impact on the organic As(V) adsorption. The mechanism study demonstrated that ion exchange and complexation played key roles in arsenic removal. This study provides a promising magnetic adsorptive material for simultaneous removal of inorganic and organic As(V).
砷是一种剧毒污染物，存在于地下水和工业废水中的无机和有机形式。将砷含量降低到较低水平（例如，饮用水中的砷含量<10 ppb）对于最大限度地降低对人类的风险非常重要。在这项研究中，通过沉淀法制备了一种 Fe-Mn-Zr 三元磁性吸附剂，用于去除无机和有机砷酸盐。通过田口法优化了吸附剂的合成，得到了具有更高吸附能力的吸附剂。砷（V）的吸附受 pH 值影响；对于无机和有机砷（V），最佳去除率分别在 pH 2 和 5 时达到。25 小时的接触时间足以完全吸附无机和有机砷（V）。吸附等温线研究表明，该吸附剂对无机砷（V）的螯合性能优于有机砷（V）；两种吸附均遵循 Langmuir 等温线，最大吸附容量分别为 81.3 和 16.98 mg/g。水中阴离子的存在对有机砷（V）的吸附比对无机砷（V）的吸附有更深远的影响。共存的硅酸盐和磷酸盐离子对两种砷（V）的吸附均产生了显著的负面影响。此外，腐殖酸的存在会降低无机砷（V）的去除率，但对有机砷（V）的吸附影响不大。机理研究表明，离子交换和络合在砷去除中起关键作用。本研究为同时去除无机和有机砷（V）提供了一种有前途的磁性吸附材料。
