Design of sisal fibre biochar/poly(dopamine)/NZVI@PAN membrane for efficient degradation of tetracycline

A modified membrane-loaded iron composite PDA/PAN/BC-Fe 0 (PPBN) was successfully prepared using sisal fibre biochar (SF-BC) and poly(dopamine) (PDA) functionalized modified hydrophilic porous polyacrylonitrile (PAN) membranes and used to support nano zero-valent iron (NZVI) for the first time. The effect of different reaction conditions and interfering factors on the degradation performance for the removal of tetracycline (TC) was investigated. In addition, the cycling and stability performance of PPBN was assessed. The agglomeration and release of NZVI particles were effectively inhibited, and the reactivity and stability of PPBN were enhanced. The results showed that under the same reaction conditions, the removal efficiency of PPBN for TC could reach 90.16% in 120 min and has increased by 36.16% compared with NZVI. After 6 regeneration cycles, the removal efficiency of TC by PPBN only decreased by 10.22%. The reaction kinetic process conformed to the two-parameter pseudo-first-order kinetic model , and three degradation pathways for TC removal were proposed. The removal mechanism included the synergistic action of physical adsorption , chemical oxidation and reduction, and the key role was played by redox reactions induced by hydroxyl radicals (∙OH) and superoxide radicals (∙O 2 − ). The results of the study provide a simple, efficient and stable material for the treatment of antibiotic wastewater.