Why Dimensionally Stable Anodes (DSA) are Used for Electrochemical Oxidation Phenol?

Why Dimensionally Stable Anodes (DSA) are Used for Electrochemical Oxidation Phenol?

Phenol belongs to the class of hazardous organic pollutants due to its high toxicity, high oxygen demand exertion, slow biodegradation, and bioaccumulation characteristics. The industrial sources of phenol and its derivatives include coal conversion, synthetic resins, textiles, pulp and paper, rubber, plastics, paints, perfumes, fertilizers and pesticides, explosives, wood preservatives, general disinfectants, medicinal preparations.

Electrochemical oxidation (EO) serves as a promising and environmentally benign advanced oxidation method for the abatement of toxic, refractory, and concentrated organic pollutants, offering ease of operation and control. This technology functions under two mechanisms: direct and indirect electrochemical oxidation. In the direct mechanism, direct charge transfer leads to the oxidation of pollutants. In indirect oxidation, electrochemically generated strong oxidant at the anode degrades contaminants in the bulk solution. The water dissociation at the anode surface (M) generates hydroxyl radicals M(•OH) as per reaction. In addition, NaCl as a supporting electrolyte acts as a mediator generating electroactive chlorine species (Cl2). which on subsequent hydrolysis generates HClO and Cl, HClO, and OCl.

Dimensionally stable anodes (DSA) represent a class of titanium (Ti) based mixed metal oxide anodes that allow the formation of superoxide as their surface (M) and •OH radicals interact strongly with each other. The selective oxidation of organic compounds (R) is then mediated by the redox couple MO/M depicts the oxygen evolution reaction (OER) which is a side reaction occurring from MO decomposition competing with an organics oxidation reaction.