Effects of biomass feedstocks on the activation of persulfate by magnetic biochar for the removal of norfloxacin

Abstract

The activation of persulfate (PS) by magnetic biochar (MBC) is a promising approach for degrading organic pollutants in water. However, the influence of biomass feedstocks on the activation performance of MBC for PS remains underexplored. In this study, three types of MBC were synthesized from sugarcane bagasse (GMBC), rice straw (DMBC), and water hyacinth (SMBC) to evaluate their effectiveness in activating PS for norfloxacin (NOR) degradation. NOR degradation experiments showed variations in NOR removal efficiency among the different MBC/PS systems. Specifically, the DMBC/PS system achieved a NOR removal efficiency of 91.53 %, which was approximately 1.32 and 1.25 times higher than those of the GMBC/PS and SMBC/PS systems, respectively. Free radical scavenging experiments and electron paramagnetic resonance (EPR) analysis confirmed that the contribution of free radicals to NOR removal varied significantly among the MBC/PS systems, indicating that the types and behaviors of free radicals were influenced by the biomass feedstocks. The active sites responsible for PS activation were identified, elucidating the variability in the contribution of active sites among different MBC/PS systems. These findings suggested that biomass feedstocks indeed played a pivotal role in influencing the activation efficiency of MBC, offering valuable insights for optimizing advanced oxidation technology based on MBC.