Multi-catalysis of glow discharge plasma coupled with FeS for synergistic removal of antibiotic.

Fe-based composites improved the energy utilization efficiency of plasma for removing contaminants through multi-catalysis have received much attention. However, the energy efficiency and catalytic activity are compromised by the slow transformation from Fe (Ⅲ) to Fe (Ⅱ). Here, given the electron-donating ability of reducing sulfur species, as well as the acidic environment generated by FeS, single FeS was introduced into the glow discharge plasma (GDP) reactor for the removal of tylosin (TYL). The results showed that a significant synergistic effect between FeS and GDP improved the energy efficiency of plasma and the removal efficiency of TYL (99.7%). FeS boosted the generation of radicals (·OH, ·O) and nonradicals (h, e) rather than HO and O, which played an important role in TYL abatement. Moreover, the electrons donating sulfur and iron species from FeS can accelerate the conversion of Fe(III) to Fe(II), which was conducive to the generation of radicals. Besides, acid solution self-adjustment resulted from the oxidation of FeS improved heterogeneous Fenton reaction, the oxidation potential of ·OH and adsorption of positive charged TYL. The plausible degradation pathways of TYL were proposed in GDP/FeS system. In summary, enhanced removal of TYL was mainly attributed to the catalytic pathway altered by FeS through high-energy electrons, photocatalysis, heterogeneous Fenton and O catalysis in the GDP system simultaneously. The strategy of integrating GDP with FeS proposed in this work is expected to offer a feasible and potential technique for organic wastewater treatment.