A Study on the Degradation Characteristics of Carbamazepine and Bisphenol S in Water

Abstract

The occurrence of pharmaceuticals and endocrine disruptors (EDCs) in aquatic environment has been demonstrated and widely evaluated in the last decade. The presence of pharmaceuticals and EDCs might have a negative impact on the quality of drinking water with unknown toxicological effects through chronic exposure (Cleuvers, 2003). The incidence of them in raw waters was used for drinking water and their elimination through treatment must be considered for health safety (Ternes et al., 2003). As examples of these kinds of compounds, carbamazepine (CBZ) is one of the well-known pharmaceuticals that have been used to treat mental impairment associated with epilepsy (Im et al., 2012), and bisphenol-S (BPS) is recently used in variety of commercial applications worldwide instead of bisphenol-A (BPA). BPS has been detected in thermal receipt paper, currency bill and canned foodstuffs (Ji et al., 2013). Advanced oxidation process (AOP) is recently applied to treat pharmaceuticals and EDCs. However, the detailed degradation mechanisms, and its identified byproducts have not been thoroughly examined. In the study, kinetics of CBZ and BPS were evaluated using ozonation and the identification of byproducts was conducted to predict its degradation pathway. Ozone was significantly attacked CBZ and BPS, and transformed the parent compound to the detected intermediates in the treatment. During 60 min of reaction, the removal (%) of CBZ and BPS decreased from 0% to 90%, but total organic carbon (TOC) decrease was not effective. During ozonation, five intermediates of CBZ (1-2-benzaldehyde-4-hydro-1H,3H-quinazoline-2-one, 1-2-benzaldehyde-1H,3H-quinazoline-2,4-dione, 1-2-benzoic acid-1H,3H-quinazoline-2,4-dione, acridine and CBZ-10,11-epoxide) and three intermediates of CBZ (molecular weight: 163, 167, and 207) were observed using LC-MSMS and Obitrap-MS. Also, three intermediates of BPS (molecular weight: 180, 202, and 224) were detected with time series. These six byproducts of CBZ and BPS in our study have never been appeared in the previous researches related to ozonation. Various degradation pathways of CBZ and BPS were elucidated in our study, and these results can be helpful to understand the fate and removal of CBZ and BPS in the ozonation.