Magnetic biochar based on platanus leaves and iron sludge for persulfate activation and catalytic degradation of tetracycline

In this study, a novel magnetic biochar (BC-Fe-n), synthesized by one-step pyrolysis at 800 degrees C using platanus leaves and iron-containing sludge in different mass ratios, was used to activate persulfate (PS) for tetracycline (TC) degradation. Results show that BC-Fe-1:2 exhibited excellent degradation performance (91.4%), much better than the raw biochar (BC) (77.1%). And electron paramagnetic resonance (EPR) techniques demonstrated radical (SO4 center dot-, center dot OH, O-2(center dot-)) and non-radical (O-1(2)) pathways in BC-Fe-1:2/PS, S O4(center dot-) was further proved to be the main active species by quenching experiments. Liquid chromatography-mass spectrometry (LC-MS) was utilized to identify the intermediates of TC and three possible degradation pathways were proposed. Additionally, the BC-Fe-1:2 was weakly affected by pH and the coexisting anions in wastewater, and could still remove 80% of TC in the third cycle experiment. This study provides a new idea for converting backwash iron-containing sludge from groundwater treatment plants into valuable catalysts, and provides new insights into the key role of low-cost magnetic biochar in PS activation.

Automated summary

In this study, a novel magnetic biochar (BC-Fe-n) was synthesized and used as a catalyst to activate persulfate (PS) for tetracycline (TC) degradation. The results demonstrated that the magnetic biochar showed excellent degradation performance and was weakly affected by pH and the coexisting anions in wastewater. This study provides a new idea for utilizing backwash iron-containing sludge as valuable catalysts and offers new insights into the key role of low-cost magnetic biochar in PS activation.