Three-dimensional photoelectrocatalytic degradation of the opaque dye acid fuchsin by Pr and Co co-doped TiO2 particle electrodes

Abstract

Herein, Pr and Co co-doped TiO2 onto flake graphite as particle electrodes were prepared and utilized for the opaque dye acid fuchsin degradation in a three-dimensional photoelectrocatalytic system. Scanning electron microscopy, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy demonstrated that Pr and Co were successfully co-doped onto the TiO2 particles and largely enhanced their surface properties and photocatalytic activity. The co-doped Pr–Co/TiO2 flake graphite particle electrodes denominated reliable acid fuchsin degradation performance under various influencing factors with the optimized operational conditions as electrolyte concentration of 0.02 mol/L, external bias voltage of 6 V, electrodes dosage of 6.67 g/L, initial pH of 2, and initial AF concentration of 20 mg/L, and aeration-free. This gave a pseudo-first order kinetic constant of 0.1313 min−1. Over 90% of AF was removed within 40 min owing to the primary contribution of hydroxyl radicals. Multiple intermediates via photoelectrocatalytic degradation of acid fuchsin were identified and a possible removal pathway was thus proposed. The three-dimensional particle electrodes photoelectrocatalytic reactor hold great potential for opaque dye wastewater treatment.