Activation of peroxymonosulfate by biochar and biochar-based materials for degrading refractory organics in water: a review

Abstract

Water pollution caused by refractory organics has attracted widespread concern in recent years. At this time peroxymonofulfate (PMS) has been widely used to generate sulfate radicals with high reactivity and potential. The direct reaction rate between PMS and organics is very low. However, the activated PMS has a strong oxidizing ability on organics due to its conversion into sulfate radicals. Recently, the free radicals generated by oxidant PMS and catalyst biochar have proven to be an effective species in dealing with refractory organics. In order to enable researchers to better understand the current research status of PMS/biochar, and to promote the development and application of PMS/biochar system, we have written this review. This review in detail described the mechanism of PMS activated by biochar materials, and summarized the influencing factors of refractory organics degradation in the PMS/biochar system. In addition, the active sites of PMS/biochar, the degradation mechanism of refractory organics, and the reusability of biochar catalysts were also discussed. Finally, the concluding remarks and perspectives were made for future research on the PMS/biochar system in the degradation of refractory organics. HIGHLIGHTS The mechanism of free radicals generated by PMS/biochar was elaborated.; The influencing factors for biochar activation of PMS were analyzed.; The mechanism and effect of PMS activated by biochar modified materials were reviewed.; The non-radical oxidation mechanism of biochar materials on refractory organics was discussed.; The existing problems and development direction of PMS/biochar research were proposed.;

Keywords

• advanced oxidation processes
• biochar
• hydroxyl radical
• peroxymonosulfate
• sulfate radical