A novel thin-layer photoelectrocatalytic (PEC) reactor with double-faced titania nanotube arrays electrode for effective degradation of tetracycline

Abstract

A novel thin-layer photoelectrocatalytic (PEC) reactor has been developed and successfully applied to the degradation of tetracycline, a typical pharmaceutical and personal care products (PPCPs), in bulk wastewater treatment. The reactor is designed with double thin-layer in order to increase the A/V ratio (ratio of electrode area and solution volume) and improve the mass transfer as well as the photonic efficiency of the system. The efficiency of organic degradation by the new reactor is much higher in comparison with conventional PEC process under similar treatment conditions. Using 20–120mgL−1 model tetracycline wastewater as the target organics, the PEC removal rate of tetracycline in the reactor reached 96.4–54.8% with a single-side illumination, much higher than that of conventional PEC reactor (about 80.4–14.6%) within 1h. When the reactor was illuminated from double sides, the treatment efficiency of thin-layer reactor was doubled without increasing new electrodes. This novel reactor always keeps high quantum efficiency regardless of the different concentration levels of the organic compounds, especially superior for the treatment of high concentration solutions. Repeated experiments in the treatment of 400mgL−1 tetracycline solution demonstrated excellent stability and reliability of the TNAs electrode.