Mn-Ce oxide-modified activated carbon composites as efficient adsorbents for removing As(iii) from water: adsorption performance and mechanisms

The efficient removal of toxic heavy metal As(iii) from water environments has become increasingly urgent due to its adverse health effects. In this study, Mn-Ce oxide-modified activated carbon (Mn-Ce/AC(x)) composites were synthesized using a simple hydrothermal process and investigated for their As(iii) adsorption performance. The Mn-Ce/AC(3) composites exhibited exceptional adsorption properties, with high oxidation and adsorption capacity for As(iii), owing to their high specific surface area (213.45 m(2) g(-1)) and the presence of surface hydroxyl groups with high affinity. At pH = 7.0, the adsorption capacity of Mn-Ce/AC(3) composites for As(iii) reached 73.16 mg g(-1). Even at very low equilibrium As(iii) concentrations, Mn-Ce/AC(3) composites could further reduce the concentration to less than 10 mu g L-1 at an initial As(iii) concentration of 10 mg L-1, which meets WHO standards. Moreover, over a wide pH range of 2-9, Mn-Ce/AC(3) composites effectively removed As(iii) by oxidation followed by adsorption, indicating that this material is a highly promising adsorbent for the treatment of As(iii)-contaminated water.