NiFe-LDH modified biochar enhances peroxymonosulfate activation system: Mechanism for singlet oxygen (1O2) generation and tetracycline degradation

The effect of biochar (BC) on the generation of reactive oxygen species (ROS) in the peroxymonosulfate (PMS) activation system remains unclear. In this study, NiFe-LDH modified BC (NiFe-LDH/BC) was synthesized to evaluate the influence of BC on ROS generation. The characterization results demonstrated that the incorporation of BC effectively enhanced the content of oxygen vacancies , which contributed to the activation of PMS. Importantly, BC facilitated the reduction of Fe(III) and Ni(III), while regulating the formation pathway of singlet oxygen ( 1 O 2 ). The ROS intermediates transformed from ·O 2- to ·OH/SO 4 ·- . Then, a greater amount of 1 O 2 was generated in the system of NiFe-LDH/BC-3/PMS, which exhibited higher TOC removal (48.7 %) compared to the NiFe-LDH/PMS system (19.2 %). The degradation mechanism and pathway of tetracycline were identified through DFT calculations and mass spectrometry detection. Meanwhile, NiFe-LDH/BC demonstrated excellent recyclability and anti-interference performance in real water bodies. Our findings would provide novel ideas to design and utilize BC-based catalytic materials to activate PMS for environmental remediation. • BC derived from vinasse coupled with NiFe-LDH was prepared for PMS activation. • BC facilitated the reduction of Ni(III) and Fe(III) in the PMS activation. • The formation pathway of 1 O 2 could be regulated with the BC introduced. • TC deconstruction mechanism was proposed by DFT calculation and UPLC-QTOF/MS.