Adsorptive and photocatalytic properties of metal oxides towards arsenic remediation from water: A review

Presence of arsenic (As) in water is both toxic and carcinogenic and is one of the most widespread problems around the globe. Metal oxides with specific affinities and high surface areas have proved to be promising adsorbents as well as photocatalysts towards arsenic removal from water. Presence of high affinity surface hydroxyl groups coupled with enormous surface area and porous surface morphology have resulted in exceptional high arsenic removal capacities from water. Arsenic removal is accompanied by the mechanisms of surface migration, deprotonation, oxidation, redox reactions, ligand exchange or charge complexations. This review critically analyses the synthesis, application of various heterostructures of metal oxide, possible mechanism towards arsenic removal from water and its usefulness over conventional adsorbents. Future scopes and challenges for robust and economical solutions towards arsenic free water have also been explored.

Automated summary

The presence of arsenic in water is a widespread issue worldwide due to its toxicity and carcinogenic nature. Metal oxides with specific affinities and high surface areas have shown promise as effective adsorbents and photocatalysts for arsenic removal. Various mechanisms including surface migration, deprotonation, oxidation, redox reactions, ligand exchange, and charge complexations are involved in the process of arsenic removal with metal oxides as heterostructures. The review critically analyzes the synthesis, application, and mechanisms of arsenic removal, while also exploring future scopes and challenges for achieving arsenic-free water solutions.