New hierarchical Ti/SnO₂-PbO₂/CNT electrode: Enhanced electrochemical properties and improved electrochemical oxidation towards various real wastewaters

Titanium-based lead dioxide (Ti/PbO₂) electrodes usually exhibit fluctuant electrochemical oxidation (EO) performance towards different real wastewaters due to their limited surface area and barely enough mineralization ability. In order to overcome these two limitations simultaneously, two additional components of carbon nanotube (CNT) and Sb-SnO₂ were introduced during the electrodeposition process of the PbO₂ layer. A new ternary hierarchical electrode format (called Ti/SnO₂-PbO₂/CNT) was successfully constructed. As comparisons, common binary CNT-embedded Ti/PbO₂ (called Ti/PbO₂/CNT) and unmodified Ti/PbO₂ were also investigated. Necessary material characterizations and electrochemical characterizations were carried out. Furthermore, two synthetic wastewaters (azo dye acid red G and P-benzoquinone) and five real wastewaters were adopted to test these electrodes comprehensively. Thanks to the hierarchical structure and CNT, the new electrode's electrochemical properties were significantly improved in voltammetric charge increase, roughness increase, and impedance decrease. Unexpectedly, the new electrode did not show obvious superiority in two synthetic wastewater treatments. However, the new electrode showed obvious advantages in three real wastewaters, especially for further degradation of intermediate and inhibition of chlorinated intermediate products. This new ternary hierarchical Ti/SnO₂-PbO₂/CNT electrode is expected to be a generalist anode for other complex real wastewaters treatment.