Mondal Monoj Kumar, Garg Ravi
Department of Chemical Engineering and Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi, Uttar Pradesh, 221005, India.
Environ Sci Pollut Res Int. 2017 May;24(15):13295-13306. doi: 10.1007/s11356-017-8842-7. Epub 2017 Apr 11.
Arsenic contamination in water bodies is a serious problem and causes various health problems due to which US Environment Protection Agency (USEPA) set its maximum permissible limit of 10 ppb. The present review article starts with the removal of toxic arsenic using adsorbents prepared from easily available waste materials. Adsorbent either commercial or low-cost adsorbent can be used for arsenic removal but recent research was focused on the low-cost adsorbent. Preparation and activation of various adsorbents were discussed. Adsorption capacities, surface area, thermodynamic, and kinetics data of various adsorbents for As(III) and As(V) removal were compiled. Desorption followed by regeneration and reuse of adsorbents is an important step in adsorption and leads to economical process. Various desorbing and regenerating agents were discussed for arsenic decontamination from the adsorbent surface. Strong acids, bases, and salts are the main desorbing agents. Disposal of arsenic-contaminated adsorbent and arsenic waste was also a big problem because of the toxic and leaching effect of arsenic. So, arsenic waste was disposed of by proper stabilization/solidification (S/S) technique by mixing it in Portland cement, iron, ash, etc. to reduce the leaching effect.
水体中的砷污染是一个严重问题，会引发各种健康问题，因此美国环境保护局（USEPA）设定了10 ppb的最大允许限值。本综述文章首先介绍了使用由易得废料制备的吸附剂去除有毒砷的方法。商业吸附剂或低成本吸附剂均可用于去除砷，但近期研究主要集中在低成本吸附剂上。文中讨论了各种吸附剂的制备和活化方法。汇编了各种吸附剂对As(III)和As(V)的吸附容量、表面积、热力学和动力学数据。吸附剂的解吸以及随后的再生和再利用是吸附过程中的重要一步，可实现经济高效的处理。文中讨论了用于从吸附剂表面去除砷污染物的各种解吸和再生剂。强酸、强碱和盐是主要的解吸剂。由于砷具有毒性和浸出效应，含砷污染吸附剂和砷废料的处置也是一个大问题。因此，通过将砷废料与波特兰水泥、铁、灰等混合，采用适当的稳定化/固化（S/S）技术进行处置，以降低浸出效应。
