Activation of peroxymonosulfate via peroxyborate: Electrophilic substitution induced strong electrophile generation process

Although sulfate radical (SO4•−) based advanced oxidation processes (AOPs) is promising for the removal of stubborn organic contaminations, low utilization efficiency of peroxymonosulfate (PMS) has practically troubled the potential application of this water treatment technology. In this study, a novel strategy for ultrafast PMS decomposition was proposed using solid peroxyborate (PBO) as the catalyst. Over 80 % of PMS can be rapidly activated within 1 min. strong electrophilic H2O2BO2 rather than commonly recognized species was considered as the reactive species causing BPA degradation. Through thermodynamic DFT calculation, the catalytic mechanism was thoroughly clarified as the electrophilic substitution reaction between protonated perboric acid (H4BO4+) and ionized PMS (SO52-). Universality experiments showed that PMS/PBO system was a promising, efficient, and eco-friendly process for the degradation of selective contaminants. This work sheds novel lights on the mechanism of electrophilic substitution induced PMS activation, and provides a new idea for environmental remediation.