Insight into the degradation of sulfamethoxazole in novel persulfate activation system based on steel slag-based geopolymer

Abstract

Due to high redox potential and long half-life, the sulfate radical based advanced oxidation processes have attracted extensive attention in the treatment of environmental pollution. Persulfate can be activated by ultraviolet light, heat and iron based materials. Among the numerous iron-based activators, steel slag has gained considerable interest as a material containing iron fractions due to their cost-effective, broad variety of sources and their ability to realize solid waste recycling. In this study, a novel proposed steel slag-based geopolymer system was applied to remove sulfamethoxazole for the first time. Sulfamethoxazole was degraded by 90.84% within 60 min in the system. Both EPR and quenching studies indicated that both SO4•− and HO• were the primary reactive oxygen species for the degradation of sulfamethoxazole. As the source of iron, steel slag-based geopolymer provide Fe species in the forms of Fe(II) and Fe(Ⅲ). Investigation on the persulfate activation mechanism suggested that both surface Fe(II) and dissolved Fe2+ contribute to persulfate activation. The presence of surface Fe(II) play dominant role on persulfate activation. The findings of this study reveal that steel slag-based geopolymer can realize the recycling of solid waste and exhibit a good job on antibiotic removal.