Enhanced Electroactivation of Peroxydisulfate with Fe-Doped MoS2 and GAC Particle Electrodes as Heterogenous Catalyst for the Degradation of Carbamazepine

The novel Fe-doped MoS2/granulated activated carbon (GAC) particle electrodes (FMG PEs) were controllably synthesized by a hydrothermal method and used in the three-dimensional (3D) electroactivation of peroxydisulfate (E-PDS-FMG) for carbamazepine (CBZ) degradation. The performance, mechanism, and influencing factors of CBZ degradation by the E-PDS-FMG system were systematically discussed. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) analyses showed that the E-PDS-FMG system has an excellent conductivity and a high electron transfer rate and exhibited a superior electrocatalytic performance for CBZ degradation. A CBZ removal rate greater than 99% can be achieved within 25 min under the conditions of FMG dosage of 0.4  g L−1, PDS concentration of 2.0 mM, current density of 1.0  mA cm−2, and initial pH value of 5. Sulfate radicals (SO4·−) and hydroxyl radicals (OH) were recognized as the major active species through quenching experiments and electron paramagnetic resonance (EPR) measurement. In addition, Fe (IV) was also involved in the E-PDS-FMG system according to the transformation of methyl phenyl sulfoxide (PMSO) to methyl phenyl sulfone (PMSO2). Furthermore, the possible mechanism of the E-PDS-FMG system was proposed. FMG PEs were applied as the catalyst and particle electrodes for PDS activation, improving the yield of OH, SO4·−, and Fe (IV). The increase of FMG dosage and PDS concentration accelerated the degradation of CBZ, and the E-PDS-FMG system exhibited a high degradation ability on CBZ removal in a wide pH range. The results all indicate that the E-PDS-FMG system is a promising technology for organic pollutant removal from water due to its excellent electrocatalytic performance and remarkable stability.