Preparation of MnCeOx-modified tea waste biochar as peroxodisulfate activator for tetracycline degradation

In this study, a MnCeOx-modified tea waste biochar was successfully prepared (MnCeOx/TBC) via impregnation-precipitation method to activate peroxodisulfate (PDS) to remove tetracycline (TC) from an aqueous solution. SEM, XRD, BET, and FTIR were used to characterize the modified biochar. MnCeOx/TBC+PDS system was highly efficient in the elimination of TC. Under the optimal conditions of MnCeOx/TBC (0.8 g·L −1 ) and PDS (6 mM), up to 98.41 % of TC was degraded at a pH of 3.0. Especially, after five cycles of MnCeOx/TBC, the removal of TC was still 94.52 %, indicating excellent catalytic stability and reusability. The quenching experiments established the major role of singlet oxygen ( 1 O 2 ) during the TC degradation, as well as the supporting role of SO 4 − , OH, and O 2 − . Further, electron paramagnetic resonance (EPR) revealed that active oxygen species including SO 4 − , OH, and O 2 − , and 1 O 2 participated in the reaction process. The analysis of intermediate products combined with toxicity prediction indicated that the toxicities of most degradation products were weaker than those of TC. These results suggested that the modification of TBC with MnCeOx is an effective method for PDS activation to remove TC.