Abstract
Pre-oxidizing trivalent arsenic (As(III)) to pentavalent arsenic (As(V)) and removing it by in-situ adsorption is an ideal choice for reducing the toxicity of arsenic-containing groundwater. In this study, a series of three-dimensional multifunctional mesoporous composites based on hydrated cerium oxide were prepared by chelating manganese oxide and hydrated cerium oxide, and then anchored on multi-walled carbon nanotubes (MWCNTs). Under the same reaction conditions, the removal performance of the three composites for As(III):[email protected] (83.37%) > CeMn-3 (63.40%) > HCO (56.90%). MWCNTs played an important role in enhancing As(III) adsorption by CeMn-3: (i) Increasing the specific surface area and regulating the average pore size of the pristine CeMn-3. (ii) Preventing Ce-Mn oxide agglomeration. (iii) Electronic shuttle for metal valence transitions. The removal efficiency of arsenic by [email protected] was hardly affected by pH (3.0–9.0) and ion concentration (0.001–0.1 M). Except for the high concentration of phosphate, inorganic anions such as sulfate, chloride, carbonate had no obvious interference. The pseudo-secondary kinetic and Langmuir adsorption model fitted better with the experimental data. The good regeneration performance and high adsorption capacity indicated that [email protected] has the potential to remove As(III) through pre-oxidation-adsorption in an aqueous environment.
Published Version
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