Recovery hydrotalcite from neutralization sludge of acid mine drainage with high manganese for degradation of norfloxacin with activated peroxymonosulfate

[Display omitted] •Catalysts MC-LDHs recovered from AMD which improved the degradation efficiency.•The adsorbed Mn in LDHs sludge was proved by DFT to be a key activate site.•ROS production pathway was clarified and the catalytic mechanism was proposed.•Norfloxacin degradation in this system was environmental safety.•The heavy metals concentration of catalyst was leached at very low level. Acid mine drainage is rich in metals (including transition metals), so the neutralization treatment based on AMD for in situ regulation will ultimately result in sludge with potential catalytic effects. In this study, we reported a catalyst (MC-LDHs) that differed from traditional catalysts in that it was derived from AMD neutralized sludge containing high concentrations of Mn, which was a typical industrial waste. The catalytic performance of activated PMS for the removal of norfloxacin (NOR, a typical antibiotic) was evaluated under different operating conditions. The contribution of active species in the reaction system was evaluated through quenching experiments, and the types of free radicals were further determined through electron spin resonance experiments. In addition, density functional theory was used to simulate the electron transfer and vulnerable sites of NOR in the adsorption of PMS by MC-LDHs. Subsequently, the degradation pathway of NOR was inferred based on DFT results, and the toxicity changes of intermediate products were predicted. This study has reduced the cost of catalysts and simplified the preparation process of doped catalysts, thus providing a new strategy for catalyst preparation, which is of great significance for the promotion and application of advanced oxidation process.