Waste self-heating bag derived CoFe2O4 composite enhances peroxymonosulfate activation: Performance, mechanism, and adaptability under high-salinity conditions

Abstract

In order to achieve the environmental goal of waste treatment by waste, waste self-heating bags, a common household waste rich in iron oxide, activated carbon, and vermiculite, were reutilized as the raw material for the one-pot fabrication of a CoFe2O4 composite (CoFe2O4-CV). The performance, mechanism, and application potential of CoFe2O4-CV for high-salinity wastewater remediation were investigated. The results indicated that the presence of activated carbon and vermiculite promoted the dispersion of CoFe2O4 nanoparticles, which enhanced the catalytic performance of peroxymonosulfate (PMS) activation for Rhodamine B (RhB) degradation. At a concentration of 0.1 g/L CoFe2O4-CV and 0.5 mmol/L PMS, > 99% of RhB was eliminated within 15 min. CoFe2O4-CV also exhibited splendid recyclability due to its strong magnetism and stability. Quenching experiments and spectroscopic studies showed that dissolved free sulfate radicals (SO4•-), surface-bound SO4•- (≡SO4•-), singlet oxygen (1O2), and high-valence metal-oxo species (≡Co(IV)=O/≡Fe(IV)=O) jointly contributed to RhB degradation. Non-radical pathways involving ≡SO4•-, 1O2, and ≡Co(IV)=O/≡Fe(IV)=O also played a crucial role. Moreover, ion competition experiments indicated that the CoFe2O4-CV activated PMS system showed anti-interference ability towards humic acid and high-concentration anions. Thus, the CoFe2O4-CV/PMS system achieved the effective removal of RhB and other dye contaminants under high-salinity conditions. This work demonstrates the practical possibility of waste reutilization treating high-salinity wastewater based on an advanced oxidation process.