Geogenic arsenic removal through core-shell based functionalized nanoparticles: Groundwater in-situ treatment perspective in the post-COVID anthropocene.

Groundwater, one of the significant potable water resources of the geological epoch is certainly contaminated with class I human carcinogenic metalloid of pnictogen family which delimiting its usability for human consumption. Hence, this study concerns with the elimination of arsenate (As(V)) from groundwater using bilayer-oleic coated iron-oxide nanoparticles (bilayer-OA@FeO NPs). The functionalized (with high-affinity carboxyl groups) adsorbent was characterized using the state-of-the-art techniques in order to understand the structural arrangement. The major emphasis was to examine the effects of pH (5.0-13), contact times (0-120 min), initial concentrations (10-150 µg L-1), adsorbent dosages (0.1-3 g L-1), and co-existing anions in order to understand the optimal experimental conditions for the effective removal process. The adsorbent had better adsorption efficiency (∼ 32.8 µg g-1, after 2 h) for As(V) at neutral pH. Adsorption process mainly followed pseudo-second-order kinetics and Freundlich isotherm models (R2∼0.90) and was facilitated by coulombic, charge-dipole and surface complexation interactions. The regeneration (upto five cycles with 0.1 M NaOH) and competition studies (with binary and cocktail mixture of co-anions) supported the potential field application of the proposed adsorbent.