Electrode improvement using diamond-like carbon for electrochemical advanced oxidation in diuron degradation

Abstract

Diuron is one of the pesticides. Its residual can contaminate natural water resource resulting in environmental and human health problems. Several processes have been used to remove diuron contamination. Nowadays, an electrochemical advanced oxidation process (EAOP) in a microchannel reactor is used to degrade diuron owing to its high efficiency. In this research, the diamond-like carbon (DLC) thin film was used as an electrochemical electrode because it has superior hardness and electrical conductivity. In this research, we have successfully synthesized the DLC thin films using graphite as target material on the surface of 304 stainless steel substrate by the direct current (dc) magnetron sputtering process. It was found that using the DLC thin film electrode caused less corrosion during the reaction when compared to the graphite electrode. The performance of diuron degradation depends on the properties of the thin film electrode, i.e., the sp2-to-sp3 ratio, the C-H bonds, and the C=O bonds. The DLC thin film electrode with the C=O bond led to the highest corrosion, up to 5.96 µg/h. The C-H bond in the DLC thin film improves the electrical conductivity (Rspecific = 0.076 Ω/nm) of electrode leading to high degradation performance, up to 70% within 100 seconds of residence time. Furthermore, each property of the DLC thin film results in different kind of intermediate during diuron decomposition.