Reusing warm-paste waste as catalyst for peroxymonosulfate activation toward antibiotics degradation under high salinity condition: Performance and mechanism study

Resourcing solid waste as catalysts for activating peroxymonosulfate (PMS) used in high-salt organic wastewater treatment, to realize waste control, is meaningful, promising, and a win–win strategy for environmental remediation. Here, a magnetically recyclable hybrid originating from used warm paste (greater than92% yield) was developed using water washing to activate PMS for antibiotics degradation under hypersaline system. Scanning electron microscope (SEM) and transmission electron microscopy (TEM) measurements indicated that the hybrid is a sheet structure with active Fe sites uniformly dispersed on the surface. The hybrid displayed an excellent PMS activation capacity; it is superior to those of classical Fe3O4 and Co3O4, which could degrade the tetracycline (TC). However, under a high-salt (0.2 mol/L Na2SO4) or mixed salts condition, the hybrid exhibited TC degradation performance. Moreover, a detailed investigation of the impact on of TC removal indicated that the preferable conditions were pH = 6, temperature = 25 °C, catalyst = 0.3 g/L and PMS = 0.3 g/L. Systematic experiments uncovered the hybrid exhibiting superb catalysis universality and adaptability in three refractory organics, 5 natural polluted water matrices, and coexisting-ions system, as well as five times, recycle processes. The surface chemical analysis combined with quenching experiment and electron paramagnetic resonance (EPR) test confirmed the PMS activation mechanism and the reactive radicals contributed in order of 1O2 > •OH > SO4•−. Considering its performance, stability and applicability, the warm paste hybrid would be good for PMS activation toward high-salt environment remediation. Thus inducing a novel direction for solid waste treatment and mitigated resource scarcity.