Electrocatalytic arsenic removal: Unveiling selective capturing and conversion with a redox-active silica-lignosulfonate hybrid framework

Addressing the global challenge of arsenic groundwater pollution to ensure a safe water supply is crucial. Thus, we developed a versatile ferrocene (Fc) incorporated silica-lignosulphonate nano framework (Fc-Si-LS). This framework was precisely designed to target and transform the toxic arsenite (As+3) into a controllable form of arsenic (As+5). Results revealed that the unique Fc-Si-LS framework had significantly targeted As+3 and showed an impressive selective conversion (84 %) performance even at high concentrations (1 mM). Additionally, in real water application (As = 150 mu g/L), the As+3 conversion rate remained effective (similar to 81.6 %). Remarkably, the synergy between Fc and Si-LS resulted in an exceptional adsorption capacity (106 mg/g) at 1.2 V, attaining a low energy consumption of only 0.072 kWh/m(3). DFT simulations established a phenomenon that simultaneous selective capturing and conversion of arsenic requires a redox moiety integration on the catalyst surface to accept electrons from the selectively trapped As+3 to the electrode. Hence, this study highlighted the potential of precisely persuading Si-LS based redox-active nano frameworks in evolving energy effective solutions for arsenic removal from drinking water, thereby offering significant implications for sustainable water treatment technologies.