Activation of persulfate with biochar for degradation of bisphenol A in soil

In this study, a new alternative activator, biochar (BC) pyrolyzed by waste biomass—lychee branch, was applied in persulfate (PS) -based remediation for bisphenol A (BPA) in soils. Radical species, solution pH, dose of PS and BC were studied to evaluate the performance of PS activation by BC to degrade BPA in aqueous solution. The results show that BC can efficiently activate PS to generate sulfate radicals and hydroxyl radicals to degrade BPA high efficiently. The increase of PS and BC dosage can increase BPA removal rate, and a lower pH is benefit for the BPA degradation in aqueous solution. In addition, the degradation intermediates of BPA were characterized and the degradation pathways were proposed. Furthermore, the PS/BC system is most efficient for BPA degradation compared with other oxidants. For soil spiked with 31.93 mg kg−1 BPA, BC can also activate PS and degrade BPA effectively. The increase of BC and PS dose cannot always increase BPA degradation because of the competition of readily oxidizable matter introduced by BC itself and/or quenching of sulfate radicals. During BPA degradation in soil, the pH value drops less than those in literatures on PS oxidation of organic contaminants in soil by other activation methods, which can alleviate soil acidification in the remediation process. The results of this study suggest a novel technique for potential application in in-situ remediation of organic contaminated sites.