Mechanism study on the removal of Cd2+ and acetamiprid from wastewater treatment plant effluent by PMS activated by tobacco stem biochar under humic acid induction.

In this study, tobacco stem based porous biochar was prepared using a direct induced etching process (HA5@TSB). The microstructure with the target functional group was confirmed through detailed SEM, FTIR, XPS, and EPR analysis. Combined with PMS for Cd(II) adsorption and acetamiprid (Ace) degradation, experiments showed that under optimal conditions, the removal rate of Cd(II) within 30 minutes was 95.48%, and the removal rate of Ace within 10 minutes was 97.21%. Through 6 consecutive removal experiments, the removal rates of Cd(II) and Ace by HA5@TSB still reached 94.56% and 97.14%, respectively, confirming its stable catalytic activity and promising prospects for effective reuse. Using different free radical scavengers, the roles and contributions of different reactive oxygen species (ROS) were elucidated (SO4-˙ (51.43%) > ˙OH (29.50%) > ˙1O2 (7.71%) > ˙O2- (3.01%)). In addition, degradation intermediates were identified by liquid chromatography/tandem mass spectrometry (LC-MS), and four degradation pathways were proposed. This superior efficiency provides great potential for the development and utilization of advanced oxidation systems for organic matter degradation and simultaneous adsorption of heavy metals using agricultural and forestry waste-based catalysts, providing alternative solutions for environmental pollution and energy crisis issues.