Electrical activation of periodate by nano-zero-valent cobalt/nitrogen-doped carbon for sulfisoxazole degradation: Insights into rapid electron transfer mechanisms.

Periodate (PI) activation via three-dimensional electrochemical (E) is a promising approach for degrading sulfisoxazole (SIZ), while the scarcity of active sites significantly limits the efficient electron-transfer rate. Herein, we synthesized multiple strongly active zero-valent cobalt (Co) nanoparticles encapsulated in nitrogen-doped carbon (NC) shells through Co-potassium chloride (KCl) doping pyrolysis of Zeolitic Imidazolate Framework-8 (ZIF-8) to induce the rapid electron transfer pathways (ETP). Specifically, molten KCl doping provides confined structures for Co with a diameter of 12.57 nm embedded in the NC shell, thereby expanding the active space of Co/NC. The generated Co/NC exhibited an enormous electrochemically active surface area (ECSA, 736.92 cm/mg), low charge transfer resistance (R, 38.50 Ω), and strong adsorption energy (-6.003 eV), which together promote robust electron transfer kinetics. Capitalizing on these properties, the E-Co/NC-PI system achieved 100% SIZ removal at a degradation rate of 1.587 min under near-neutral (pH 5.00-9.00) conditions, with ultra-low energy consumption (0.011 kWh m, $0.125/L). This study highlights a Co/NC-induced rapid ETP for SIZ removal, offering insights into enhanced electrical activation of PI for wastewater treatment.