Institute for Water Resources and Water Supply, Hamburg University of Technology, Am Schwarzenberg-Campus 3, 20173, Hamburg, Germany.
Department of Chemistry, Laboratory of Chemical and Environmental Technology, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
Environ Sci Pollut Res Int. 2021 Nov;28(42):59063-59075. doi: 10.1007/s11356-020-08327-w. Epub 2020 Apr 10.
Arsenic is among the major drinking water contaminants affecting populations in many countries because it causes serious health problems on long-term exposure. Two low-cost micro-sized iron oxyhydroxide-based adsorbents (which are by-products of the industrial production process of granular adsorbents), namely, micro granular ferric hydroxide (μGFH) and micro tetravalent manganese feroxyhyte (μTMF), were applied in batch adsorption kinetic tests and submerged microfiltration membrane adsorption hybrid system (SMAHS) to remove pentavalent arsenic (As(V)) from modeled drinking water. The adsorbents media were characterized in terms of iron content, BET surface area, pore volume, and particle size. The results of adsorption kinetics show that initial adsorption rate of As(V) by μTMF is faster than μGFH. The SMAHS results revealed that hydraulic residence time of As(V) in the slurry reactor plays a critical role. At longer residence time, the achieved adsorption capacities at As(V) permeate concentration of 10 μg/L (WHO guideline value) are 0.95 and 1.04 μg/mg for μGFH and μTMF, respectively. At shorter residence time of ~ 3 h, μTMF was able to treat 1.4 times more volumes of arsenic-polluted water than μGFH under the optimized experimental conditions due to its fast kinetic behavior. The outcomes of this study confirm that micro-sized iron oyxhydroxides, by-products of conventional adsorbent production processes, can successfully be employed in the proposed hybrid water treatment system to achieve drinking water guideline value for arsenic, without considerable fouling of the porous membrane. Graphical abstract.
砷是影响许多国家人口的主要饮用水污染物之一，因为它会导致长期暴露产生严重的健康问题。两种低成本的微尺度铁基氢氧化物吸附剂（是颗粒吸附剂工业生产过程的副产品），即微颗粒氢氧化铁（μGFH）和微四价锰铁氧体（μTMF），被应用于批式吸附动力学试验和浸没式微滤膜吸附混合系统（SMAHS），以去除模型饮用水中的五价砷（As(V)）。通过铁含量、BET 表面积、孔体积和粒径对吸附剂介质进行了表征。吸附动力学的结果表明，μTMF 对 As(V)的初始吸附速率较快。SMAHS 的结果表明，浆液反应器中 As(V)的水力停留时间起着关键作用。在较长的停留时间下，在 As(V)透过浓度为 10μg/L（世界卫生组织指导值）时，μGFH 和 μTMF 的吸附容量分别为 0.95 和 1.04μg/mg。在停留时间较短（约 3 小时）的情况下，在优化的实验条件下，μTMF 能够处理比 μGFH 多 1.4 倍的受砷污染的水，这是由于其快速的动力学行为。本研究的结果证实，传统吸附剂生产工艺的副产品，即微尺度铁氧体氢氧化物，可以成功地应用于所提出的混合水处理系统，以达到饮用水砷的指导值，而不会对多孔膜造成严重的污染。
