Advanced application of nano-technological and biological processes as well as mitigation options for arsenic removal

[Display omitted] •Arsenic removal by precipitation, adsorption, oxidation, ion- exchange, bio-adsorption etc.•Arsenic oxidation (vital step in removal) is achieved by O2/O3/HClO/KMnO4/H2O2/microbe.•Effective absorbent: Fe-based nano/composite, Al2O3, Fe-Al2O3, Fe-TiO2, CeTiO2, etc.•Ecofriendly As removal (water and soil): Phytoremediation/microbe, Seed priming, Hybrid and BAT.•As mitigation: Proper adsorbent, As safe aquifer, rainwater harvesting, etc. Arsenic (As) removal is a huge challenge, since several million people are potentially exposed (>10 μg/L World Health Organization guideline limit) through As contaminated drinking water worldwide. Review attempts to address the present situation of As removal, considering key topics on nano-technological and biological process and current progress and future perspectives of possible mitigation options have been evaluated. Different physical, chemical and biological methods are available to remove As from contaminated water/soil/wastes, where removal efficiency mainly depends on absorbent type, initial adsorbate concentration, speciation and interfering species. Oxidation is an important pretreatment step in As removal, which is generally achieved by several media such as O2/O3, HClO, KMnO4 and H2O2. The Fe-based-nanomaterials (α/β/γ-FeOOH, Fe2O3/Fe3O4–γ-Fe2O3), Fe-based-composite-compounds, activated-Al2O3, HFO, Fe-Al2O3, Fe2O3-impregnated-graphene-aerogel, iron-doped-TiO2, aerogel-based- CeTiO2, and iron-oxide-coated-manganese are effective to remove As from contaminated water. Biological processes (phytoremediation/microbiological) are effective and ecofriendly for As removal from water and/or soil environment. Microorganisms remove As from water, sediments and soil by metabolism, detoxification, oxidation-reduction, bio-adsorption, bio-precipitation, and volatilization processes. Ecofriendly As mitigation options can be achieved by utilizing an alternative As-safe-aquifer, surface-water or rainwater-harvesting. Application of hybrid (biological with chemical and physical process) and Best-Available-Technologies (BAT) can be the most effective As removal strategy to remediate As contaminated environments.