Efficiency and mechanism of phosphoric acid modified biochar loaded nanoscale zero-valent iron activated peroxymonosulfate for the degradation of bisphenol A.

• Phosphoric acid-modified biochar-supported nZVI is prepared. • BPA degradation rate reaches to 92.66 % within 60 min under optimized conditions. • The •OH, •SO 4 −, •O 2 −, and 1O 2 are involved in the PMS-based degradation of BPA. • The 1O 2 plays a prominent role in the degradation of BPA over PBC/nZVI/PMS system. • BPA is degraded through •OH-induced oxidation and SO 4 •−-induced hydroxylation. The degradation efficiency of bisphenol A (BPA) using sulfate radical-based advanced oxidation processes still requires further improvement. Herein, we prepared phosphoric acid-modified biochar-supported nZVI (PBC/nZVI) through liquid-phase reduction. Under optimized conditions, including a PBC/nZVI dosage of 1.2 g/L, pH 9.0, and PMS concentration of 2.0 mmol/L, the BPA degradation rate reached up to 92.66 % within 60 min with the mineralization rate of 45.5 %. The presence of Cl−, HCO 3 − and CO 3 2− promoted the degradation of BPA, while NO 3 − had minimal effect. Conversely, H 2 PO 4 − and humic acid exhibited varying degrees of inhibition. The degradation of BPA involved four reactive oxygen species (•OH, SO 4 •−, O 2 •−, and 1O 2), with 1O 2 playing a prominent role. The pathways of •OH-induced oxidation and SO 4 •−-induced hydroxylation were identified as the mechanisms through which BPA was degraded. These findings highlighted the potential of PBC/nZVI as a rapid and efficient material for BPA degradation. [ABSTRACT FROM AUTHOR]