Mechanism and application of enhanced degradation of phenol through peroxymonosulfate activation by sulfur-doped biochar prepared with sodium thiosulfate as activator and sulfur dopant

Na2S2O3 was used as activator and sulfur dopant for preparation of sulfur-doped biochar (SBC) with high specific surface area and sulfur content, and its performance to activate peroxymonosulfate (PMS) for phenol degradation was studied. In the presence of 0.3 g/L S4BC-800 and 1 g/L PMS, 20 mg/L phenol could be removed completely in 30 min. S doping improved the electron transfer performance of the composite and enhanced the activation property of PMS for phenol degradation. Free radical quenching experiment and electron paramagnetic resonance analysis indicated that SO4•−, •OH, and 1O2 were involved in phenol degradation. In addition, the current oxidation process confirmed that there was also direct oxidation based on electron transfer between PMS and phenol with S4BC-800 as mediator. The S4BC-800/PMS system could effectively decompose the recalcitrant organic pollutants in the effluent of sewage treatment plant, achieving the total organic carbon removal rate of 83.26 %.