Electrochemical oxidation degradation of Rhodamine B dye on boron-doped diamond electrode: Input mode of power attenuation

Electrochemical oxidation is a rapid and efficient technology to remove organic matter from wastewater, but the most obvious defects are low current efficiency and high energy consumption. This paper presents a novel power supply mode with power attenuation. The attenuated power is periodically input to the reaction system to improve the average current efficiency and reduce energy consumption. The removal efficiency, current efficiency and energy consumption of treating Rhodamine B were compared between the two modes of power attenuation and the conventional direct current. Applying current attenuation in the step-Mode A1, 98.58% Rhodamine B was decomposed and the COD removal efficiency was 91.47%. The current efficiency reached 18.49% and electrocal energy consumption was only 44.58 kWh∙m−3. Under the conditions of the same removal efficiency of Rhodamine B, the current efficiency of Mode A1 was 2.04 times larger than that of Mode D1, and the energy consumption was only 45.41% of Mode D1. Five cycles of experiments show that the boron-doped diamond electrode has obvious stability and reusability in the electrochemical oxidation process. ·OH was the main active substance involved in Rhodamine B degradation. The power attenuation mode to treat Rhodamine B dyes electrochemically will be the most promising saving energy method for efficient processing dyes wastewater in the future.