Study on persulfate activated by Ce-modified tea waste biochar to degrade tetracycline

In this study, the Ce-modified tea residue biochar (Ce-TBC) was successfully generated and applied to the biochar/persulfate system (Ce-TBC/PDS), the mechanism of the removal of tetracycline (TC) using Ce-TBC/PDS was elaborated. Under the optimal experimental conditions (Ce-TBC = 0.8 g L-1, PDS = 4 mM, TC = 10 mg L-1), the removal efficiency of TC was 91.28%, and after 5 cycles, the elimination rate of Ce-TBC/PDS still reached up to 80%. The mechanism of TC removal by Ce-TBC/PDS was analyzed by scanning electron microscopy (SEM), X-ray diffractometer (XRD), Fourier infrared transform spectrometer (FT-IR), and X-ray photoelectron spectrometer (XPS) characterization, and influence factor experiments. The results showed that the introduction of CeOx increased the oxygen vacancies on the TBC surface and promoted the interconversion between Ce3+ and Ce4+ for better activation of PDS and generation of active species. Free radical quenching experiments and paramagnetic resonance spectrometry (EPR) analysis showed that the non-radical pathway O-1(2) played a dominant role in the Ce-TBC/PDS system. The present work provided an efficient means of PDS activator and recycling of tea waste.

Automated summary

In this study, Ce-modified tea residue biochar (Ce-TBC) was used in the biochar/persulfate system to remove tetracycline (TC). The mechanism of TC removal was investigated through various characterization techniques and influence factor experiments. The results showed that the introduction of CeOx enhanced the activation of persulfate and the generation of active species. The non-radical pathway O-1(2) played a dominant role in the Ce-TBC/PDS system.