Metal-Organic Frameworks for Dual Photo-Oxidation and Capture of Arsenic from Water

Abstract

Despite rapid technological progress, heavy metal water pollution, and particularly arsenic contamination, remains a significant global challenge. In addition, the stabilization of trivalent arsenic as neutral arsenite (As^III) species hinders its removal by conventional sorbents. While adsorption of anionic arsenate (As^V) species is in principle more feasible, there are only few adsorbents capable of adsorbing both forms of arsenic. In this work, we explore the potential of two well-known families of Metal-Organic Frameworks (MOFs), UiO-66 and MIL-125, to simultaneously adsorb and photo-oxidize arsenic species from water. Our results demonstrate that the formation of As^V ions upon light irradiation promotes the subsequent adsorption of As^III species. Thus, we propose the combined utilization of photocatalysis and adsorption with Metal-Organic Framework photocatalysts for water remediation purposes.