Degradation of residual xanthate in flotation tailing wastewater by activated H2O2 with natural ilmenite: A heterogeneous fenton-like reaction catalyzed at natural pH

Abstract

Efficient treatment of residual xanthate from tailing wastewater has attracted soaring interesting recently. Herein, effect of activated H2O2 by natural ilmenite (FeTiO3) as a catalyst on sodium butyl xanthate (SBX) degradation was systematically investigated. More than 98 % SBX degradation efficiency was achieved by the method under optimal conditions (a natural pH = 8.7, [FeTiO3]0 = 4.0 g/L, [H2O2]0 = 2.0 mM, and [SBX]0 = 40.0 mg/L), and chemical oxygen demand (COD) removal rate was 85.41 %. Kinetic studies indicated that SBX degradation efficiency in FeTiO3-H2O2 system conformed with a pseudo first order kinetic equation. Also, comparative experiments indicated that this system degraded SBX was superior to the H2O2 alone and FeTiO3 alone systems. Reactive oxygen species (ROS) were determined by quenching experiments and electron paramagnetic resonance (EPR) tests, suggesting that OH and O2− were the primary reactive radicals in FeTiO3-H2O2 system. Cycling experiments and leaching metal ion tests suggested that FeTiO3 still exhibited high catalytic activity and excellent stability after five times of recycling. Finally, possible degradation pathways and mechanism of SBX in this system were proposed. Consequently, this study promotes the application of natural iron-based minerals as a catalyst in wastewater treatment, and provides new insights into the effective treatment of organic pollutants in tailing wastewater.