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Adsorption of arsenic by activated charcoal coated zirconium-manganese nanocomposite: Performance and mechanism

Yin, Yuwei, Zhou, Tingting, Luo, Hanjin, Geng, Junjie, Yu, Wenyi, Jiang, Zhongjie
Colloids and surfaces 2019 v.575 pp. 318-328
activated carbon, adsorption, anions, arsenic, bicarbonates, chlorides, drinking water, fluorides, manganese, manganese dioxide, nanocomposites, nitrates, oxidation, phosphates, pollution, sorbents, sulfates, surface area, toxicity, zirconium, zirconium oxide
As(III) is more toxic and harder to remove than As(V) though they are always co-exist in water. In order to effectively eliminate pollution of arsenic and explore the adsorption mechanism, a novel-innovative hydrated zirconium oxide (ZrO(OH)2) and manganese dioxide (MnO2) coated modified activated charcoal (Zr/Mn/C) prepared via a co-precipitation-hydrothermal method. Results showed that As(III) can be oxidized to As(V) by the MnO2 and then adsorbed by ZrO(OH)2, the toxicity reduced and the ability of Zr/Mn/C to remove As(III) is efficiently enhanced. The maximum adsorption capacity of As(V) and As(III) are 95.60 mg/g and 132.28 mg/g, respectively. The outstanding removal performance benefits from the large specific surface area of the modified activated charcoal, which makes agglomeration phenomenon weakened, and the ZrO(OH)2 and MnO2 can homogeneously distribute on the surface of carrier. The residual concentrations of As(V) and As(III) can drop under 7.0 ug/L, meeting the standards of drinking water with initial concentrations under 9mg/L and 1mg/L, respectively. Meanwhile, the nanocomposite exhibits excellent interference rejection from various co-existing anions such as: Cl−, F−, NO3−, SiO32-, PO43-, SO42- and HCO3−, it can be used in different water environments. In short, the Zr/Mn/C is a promising sorbent with a great potential for removing arsenic.