Adsorption and activation of peroxymonosulfate on BiOCl for carbamazepine degradation: The role of piezoelectric effect

The adsorption of peroxymonosulfate (PMS) is crucial for PMS activation in the heterogeneous advanced oxidation processes. However, the investigation of PMS adsorption on the piezocatalysts still remains insufficient. In this work, bismuth oxychloride (BiOCl) nanosheets were prepared as the piezocatalysts for PMS activation under ultrasonic vibration to remove carbamazepine (CBZ) in aqueous solutions. Up to 92.5% of CBZ was degraded for 40 minutes in BiOCl piezo-activated PMS system with the reaction rate constant of 0.0741 min−1, being 1.63 times that of the sum of BiOCl piezocatalysis, BiOCl-activated PMS, and vibration-activated PMS. PMS adsorption on the surface of BiOCl was specifically studied by comparing the microscopic structure change of the fresh and used BiOCl. The results suggested that the piezoelectric field of BiOCl was able to promote the tight adsorption of PMS on the surface, thus facilitating the fast activation of PMS through electrons transfer to produce reactive species (HO•, SO4•−, O2•−, 1O2). This work presents an in-depth understanding for the role of piezoelectric effect on the adsorption and activation of PMS.