Development of biochar supported NiFe2O4 composite for peroxydisulfate (PDS) activation to effectively remove moxifloxacin from wastewater
T. Hien Nguyen, Hoan Nguyen Xuan, Truong Giang, Lan Huong Nguyen
Abstract
Waste durian peels derived-biochar (DP-BC) supported magnetic nickel ferrite (NiFe2O4) was successfully synthesized at various composite ratios of 5, 10, 15, 20, 25 and 30% between NiFe2O4 NPs and DP-BC. The nanocomposites (DP-BC@NiFe2O4) were then applied to activate peroxydisulfate (PDS) for the removal of moxifloxacin (MFX) from wastewater. The textural, morphology, and structure properties of the DP-BC@NiFe2O4 were systematically characterized. The initial catalytic activity of DP-BC@NiFe2O4 was assessed through the MFX degradation efficiency in the DP-BC@NiFe2O4/PDS systems. The results showed that the pyrolysis temperature of 350°C gave the highest removal of MFX in the PDS system activated by DP-BC. Besides, loading 15% of NiFe2O4 onto DP-BC gave the highest degradation efficiency of MFX in the DP-BC@NiFe2O4/PDS system with a MFX removal of 88.6 % for 90 min reaction. Based on catalyst's property data and quenching tests using different scavengers, the primary mechanisms of MFX degradation by DP-BC@NiFe2O4/PDS system were through both radical and non-radical pathways thanks to effective formation of reactive oxygen species (ROS), consisting of hydroxyl (*OH), sulfate (*SO4−), superoxide (*O2) and singlet oxygen (1O2) during catalytic reactions. Among ROS, the singlet oxygen (1O2) participated mainly in MFX degradation. The increased formation of ROS in the DP-BC@NiFe2O4/PDS system was due to enhanced PDS activation by the redox reaction a couple of Fe3/Fe2+ and Ni3+/Ni2+ and electron transfer of DP-BC biochar's abundant oxygen-containing surface functional groups. Therefore, it is confirmed that BC@ NiFe2O4 exhibited good catalytic activity in the activation of PDS to effectively remove MFX from wastewater.