Electrochemical removal of tetrahydrofuran from industrial wastewaters: anode selection and process scale-up.

BACKGROUND In this work, industrial wastewaters with an average tetrahydrofuran ( THF) concentration of 688 ± 140 mg L⁻¹ were treated by electrooxidation. Four anodic materials were tested: RuO₂, Pt, PbO₂ and boron-doped diamond ( BDD). Bench scale experiments (volume treated 1 L, anode area 140 cm²) and pilot scale tests (volume treated 200 L, anode area 2800 cm²) were performed, and the influence of the applied current density, in the range 300 < j_app <1200 A m⁻², was assessed. RESULTS BDD was the only anodic material that enabled fast THF degradation and mineralization, using sodium sulfate as electrolyte. Dimensionally stable oxides such as RuO₂ with sodium chloride as electrolyte did not achieve mineralization of the organic pollutants. Bench scale experiments allowed the kinetics of THF degradation to be described. The electrooxidation process, under mass transfer control, was enhanced by the contribution of electrogenerated secondary oxidants. The kinetic model and parameters used for the process scale up were fully validated by the excellent matching between the model predictions and the experimental results obtained at pilot scale. CONCLUSIONS The electrochemical treatment using BDD anodes allows the removal and mineralization of tetrahydrofuran contained in industrial wastewaters generated in rubber manufacturing. Process scale-up, based on the kinetic model obtained from bench scale data, was successfully achieved. Energy consumption can be optimized by applying current modulation strategies. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]