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

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 CoFe 2 O 4 composite (CoFe 2 O 4 -CV). The performance, mechanism, and application potential of CoFe 2 O 4 -CV for high-salinity wastewater remediation were investigated. The results indicated that the presence of activated carbon and vermiculite promoted the dispersion of CoFe 2 O 4 nanoparticles , which enhanced the catalytic performance of peroxymonosulfate (PMS) activation for Rhodamine B (RhB) degradation. At a concentration of 0.1 g/L CoFe 2 O 4 -CV and 0.5 mmol/L PMS, > 99% of RhB was eliminated within 15 min. CoFe 2 O 4 -CV also exhibited splendid recyclability due to its strong magnetism and stability. Quenching experiments and spectroscopic studies showed that dissolved free sulfate radicals (SO 4 •- ), surface-bound SO 4 •- (≡SO 4 •- ), singlet oxygen ( 1 O 2 ), and high-valence metal-oxo species (≡Co(IV)=O/≡Fe(IV)=O) jointly contributed to RhB degradation. Non-radical pathways involving ≡SO 4 •- , 1 O 2 , and ≡Co(IV)=O/≡Fe(IV)=O also played a crucial role. Moreover, ion competition experiments indicated that the CoFe 2 O 4 -CV activated PMS system showed anti-interference ability towards humic acid and high-concentration anions. Thus, the CoFe 2 O 4 -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 .