One-step synthesis of CoxS/Ni3S2@NF on 3D nickel foam with different sulfur sources as a novel heterogeneous catalyst efficient activation of peroxymonosulfate in lomefloxacin degradation

In this study, we have successfully synthesized Co9S8/CoS/Ni3S2 and Co3S4/Ni3S2 materials in situ on three-dimensional (3D) nickel foam (NF) substrates using a one-step hydrothermal process with different sulfur sources. Under the experimental conditions of catalyst dosage of 0.50 cm × 0.50 cm and peroxymonosulfate (PMS) dosage of 0.30 g/L, the Co3S4/Ni3S2@NF catalyst exhibited superior catalytic performance in activating PMS and degrading 91.0 % of lomefloxacin (LOM) as compared to 76 % of Co9S8/CoS/Ni3S2@NF. Both Co9S8/CoS/Ni3S2@NF and Co3S4/Ni3S2@NF showed excellent stability and performed effectively over a wide pH range. The Co9S8/CoS/Ni3S2@NF and Co3S4/Ni3S2@NF demonstrated significant differences in morphology, crystal plane properties, surface functional groups, chemical composition, elemental valence states, and coordination environment as revealed by XRD, TEM, SEM, FTIR, and XPS analyses, contributing to their distinct mechanisms and performance in LOM degradation. Additionally, the NF acted as a support carrier, exposing multiple active sites to enhance electron transport and providing a nickel source for the catalytic reaction. The degradation of LOM in the CoxS/Ni3S2@NF&PMS system was thoroughly investigated, revealing the involvement of SO4−, OH, 1O2, and electron transfer in the process. Additionally, the mechanism of PMS activation and the pathway of LOM decomposition in the reaction system were elucidated by theoretical analysis. Furthermore, the ecotoxicity of the by-products generated during LOM degradation was assessed using the ECOSAR software. In summary, the CoxS/Ni3S2@NF catalysts proved to be efficient, stable, easily prepared, environmentally friendly, and recyclable heterogeneous nanocomposites. It is a promising candidate for heterogeneous PMS process.