Gallic acid reinforced carbon-based materials for peroxymonosulfate activation to p-nitrophenol degradation
Oily sludge carbon-based materials(OSC)were prepared from pyrolysis of oily sludge(OS),used as heterogeneous activator for permonosulfate(PMS,potassium peroxymonosulfate)to degrade p-nitrophenol(PNP),and characterized by XRD,SEM,EDS and XPS for analysis on the microscopic morphology and elemental valence.The effects of different reaction systems,pyrolytic temperature of carbon-based material,gallic acid(GA)concentration,PMS concentration,initial solution pH,reaction temperature,PNP mass concentration,co-existing anion type and xanulinic acid(FA)mass concentration on the degradation of PNP by OSC activated PMS were evaluated.The results demonstrated that the surface hydroxyl groups on OSC-800 and the valence cycle between Fe3+and Fe2+were involved in the activation of PMS,and GA introduction greatly accelerated PNP degradation,with the OSC-800 prepared at 800℃showing the best activation performance in the OSC-800/PMS/GA system.Under the conditions of OSC-800 solid-liquid ratio(g∶L)2∶1,initial solution pH 6.7,PMS concentration 1.4 mmol/L,GA concentration 0.25 mmol/L,PNP mass concentration 20 mg/L and reaction temperature 25℃,the PNP degradation rate reached 88.14%within 100 min.The PNP degradation rate constant(0.0191 min-1),COD removal rate(76.01%)and PMS utilization rate(93.44%)were increased by 194%,65%and 190%compared with those of OSC-800/PMS system.OSC-800/PMS/GA system produced·SO4-,·OH,·O2-and singlet oxygen in the reaction.