High-efficiency treatment of lead-zinc beneficiation wastewater by Fenton (FT) coupled with micro-nano bubbles (MNBs): effective utilization of H2O2

Abstract

Mineral processing wastewater residues large amounts of organic flotation reagents (xanthate and No. 2 oil), posing environmental and health risks. Traditional Fenton (FT) methods face limitations like acidic pH dependence, low efficiency, and reagent waste. This study first introduces a stepwise FT process coupled with micro-nano bubbles (MNBs) to enhance treatment efficiency of difficult-to-degrade lead–zinc beneficiation wastewater. The MNBs-assisted system achieved 85.43 % COD (chemical oxygen demand) removal in 60 min, while only 38.54 % was achieved without MNBs, and extended pH applicability to neutral. With thermal activation, COD decreased from 1008.00 to 96.65 mg/L, which meeting GB25466 − 2010 discharge limit and achieving 90.3 % degradation. MNBs significantly improved H₂O₂ utilization, demonstrating industrial potential.