Ball Milling Enhanced Magnetic Corn Straw Biochar for Peroxyacetic Acid Activation Towards Efficient Degradation of Sulfadiazine

Abstract

A heterogeneous catalyst of ball-milling magnetic corn straw biochar (BMCBC) was the first time synthesized to activate peroxyacetic acid (PAA) for efficient degradation of sulfadiazine (SDZ). The results showed that large surface area and magnetic Fe3O4 of BMCBC enhanced its activation performance for PAA. The removal efficiency of SDZ could reach 93% within 60 min in PAA/BMCBC system. Solution pH, CO32-, NO3-, Cl- were the critical environmental factors affecting the degradation process, can inhibit the degradation process. The reactive oxygen species (ROS) identification, quenching experiments and Raman spectra analysis demonstrated that •OH and R-O• were the main contributors to SDZ degradation. All of SDZ were oxidated into less toxic transformed products (TPs). Three degradation pathways of SDZ were proposed and Pathway III was considered as the dominant degradation pathway. Also, PAA/BMCBC system built in this study exhibited the excellent high removal rates for SDZ in real waters including Yangtze River water (84.32%), lake water (73.95%), tap water(93.3%) and pure water (91.29%). Additionally, BMCBC showed the good environmental safety in a wide pH range (from 5 to 11) with the low leaching levels of Fe. The magnetic sensitivity of BMCBC allowed it to be easily collected within 10 min, and it could maintain sustainable activation performance for PAA even after four reuse cycles. This study developed a promising method for antibiotics elimination, as well as the resource utilization of corn straw.

Keywords: Sulfadiazine, Corn straw, Peroxyacetic acid, Ball milling, Magnetic modification