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. © 2024 Fine Chemicals. All rights reserved.