Insights into nitrogen doped sulfur-existed carbonaceous material toward acetaminophen removal by peroxymonosulfate activation

Heteroatom doping into the carbon matrix has been widely accepted to overcome the electronic inertness of carbonaceous material. In this study, N was doped into carbonaceous material within S to evaluate the peroxymonosulfate (PMS) activation performance of the obtained carbocatalyst for the degradation of acetaminophen (ACE). The results demonstrated that individually N or S doped carbocatalysts could activate PMS, but only N doping exhibit significant PMS activation performance. More interestingly, simultaneously co-existed of N and S exhibited obviously lower PMS activation performance than individual N doping. Density functional theory (DFT) calculation exhibited that N doped carbon matrix possessed more positive surface electrostatic potential than N and S co-doped carbocatalyst, amongst S exhibited opposite electronic structure regulation compared with N. Therefore, the PMS activation performance of N doped carbon was significantly higher than that by N and S co-existed carbon. SO4-, HO,1O2 and O2- was involved in the reaction, the result shown that singlet oxygen amplified the non-radical mechanism and the electron transfer from adsorbed organic pollutant to adsorbed PMS was the another dominated pathway to the ACE degradation. Further experiments unraveled that higher PMS concentration, catalysts dosage, and lower initial solution pH would facilitate the PMS activation process.