Efficient degradation of organic pollutants by activated peroxymonosulfate over TiO2@C decorated Mg–Fe layered double oxides: Degradation pathways and mechanism

To activate peroxymonosulfate (PMS) is an efficient way for decomposition of non-biodegradable organic pollutants. Herein, Mg–Fe layered double oxides decorated with Ti 3 C 2 MXene-derived TiO 2 @C (T/LDOs) were fabricated to efficiently activate PMS for the degradation of Rhodamine B (RhB), acid red 1 (AR1), methylene blue (MB), and tetracycline hydrochloride (TC). The T/LDOs catalyst could decompose 95.8% of RhB, 94.8% of AR1, 84.9% of MB within 10 min, and 82.4% of TC within 60 min. The degradation rate constant of RhB in the optimal T/LDOs/PMS system was approximately 2.5 and 15.7 times higher than that in the Mg–Fe LDOs/PMS system and Mg–Fe LDH/PMS system, respectively. Importantly, the T/LDOs exhibited a wide working pH range (3.1–11.0) and high stability with low metal ions leaching, indicating its potential practical applications. Quenching experiments and electronic spin resonance results confirmed that both • O 2 − and 1 O 2 were the dominant active species in the T/LDOs/PMS system. In addition, the possible degradation pathway of RhB in the 5%-T/LDOs/PMS system was proposed. Finally, the catalytic mechanism study revealed that the T/LDOs with abundant surface hydroxyl groups and a certain amount of TiO 2 @C facilitated the electron transfer between ≡Fe (Ⅲ) ‒OH complex and HSO 5 − , boosting the generation of • O 2 − and 1 O 2 . This study provides an insight into exploiting highly efficient catalysts for PMS activation towards the degradation of organic pollutants.