Potential-modulated Electrocatalytic platform for sustainable recovery of critical metals and synergistic mineralization of Perfluorinated contaminants: Unraveling atomic-level interface dynamics in multi-ion systems

Abstract

This study used bamboo charcoal etched with humic acid and carbonized at high temperatures from bamboo as a particle electrode to construct a DCHA@BC system for treating wastewater containing Mn²⁺, Cd²⁺, Ni²⁺, Cu²⁺ and PFOA. The study found that within 45 min, the removal rates of Mn²⁺, Cd²⁺, Ni²⁺, Cu²⁺ and PFOA reached their maximum, which were 95.23 %, 90.07 %, 84.17 %, 80.47 % and 91.06 %, respectively. At this time, the energy consumption was only 15.71 kWh/kg Mn²⁺. Characterization analysis shows that HA@BC electrode enhances the electric field, promotes mass transfer of PFOA, reduces nucleation overpotential, accelerates the electrodeposition kinetics of cations, thereby accelerating the reduction of cations. The presence of electrochemistry accelerates the shortening of the C chain and the release of F⁻ in PFOA by promoting the activation of PMS, thereby achieving mineralization of PFOA. The results of EPR and quenching experiments indicate that HO^· and SO^·₄⁻ play a crucial role in the degradation process of PFOA. After 8 cycles, the maximum removal rates of cations and PFOA by the DCHA@BC system only decreased by 1.33–3.376 %. This indicates that the DCHA@BC system has good stability. This study innovatively combines micro battery design and electrochemical technology, significantly improving the recovery of heavy metals and the efficient degradation of perfluorooctanoic acid, providing valuable insights for the treatment of high concentration industrial wastewater.