A magnetic biomass/MOF composite as a functional material for the oxidative removal of tetracycline: Degradation mechanism and toxicity study

Nitrogen doped magnetic biomass materials offers unique advantages for wastewater remediation processes. In this study, the mechanisms underlying activation of peroxydisulfate (PS) using a magnetic biomass/MOF composite (MPN@NH2-MIL-101(Fe)) endowed with nitrogen atoms for the removal of tetracyclines (TC) from wastewater was investigated. Results of the study proved the significant role of nitrogen atoms in enhancing the degradation efficiency due to the non-radical degradation pathway. Quenching experiments and electron paramagnetic resonance (EPR) investigations indicated that singlet oxygen (1O2), hydroxyl (HO•) and sulfate (SO4•-) radicals were responsible for the catalytic degradation of TC albeit the chemisorption process may also occur simultaneously. In addition, MPN@NH2-MIL-101 (Fe) was found to have good biocompatibility and a good mineralization efficiency resulting in benign intermediates as was confirmed by the significant improvement in the cytotoxicity of TC treated effluents towards human embryonic kidney (HEK) cells. MPN@NH2-MIL-101(Fe)/PS system exhibited an ultra-fast (5 min) and appreciable degradation efficiency towards TC in real water samples albeit this was dependent on the water matrix. These properties coupled with the low cost involved in its development as recorded from the cost analysis may corroborate its economic feasibility and prospects for practical applications.