Base-metal oxide semiconductor electrodes for PPCP degradation: Ti-doped α-Fe2O3 for sulfosalicylic acid oxidation as an example. (February 2023)

• Record Type: Journal Article
• Authors: Zhang, Shuchi; Tan, Mengyu; Du, Shuwen; Leng, Wenhua; Wu, Donglei
• Is Part Of: Chemosphere. Volume 313(2023)
• Publication Date: 2023-02
• Subjects: Faraday efficiency -- Kinetic -- Adsorption -- Oxidation pathway -- Charge transfer; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.137354
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Sulfosalicylic acid is a typical pharmaceutical and personal care product with high toxicity, environmental persistence, and low biodegradability. Electrochemical oxidation has been demonstrated to be a promising way for hazardous organics treatment, but it is severely limited by the high cost and resource shortage of electrode materials. Base-metal oxide semiconductor anodes have the merits of low cost, diversity, and tunable energy levels for charge transfer, and thus may be alternatives to the electrodes for wastewater treatment. Herein, we found that Ti-doped α -Fe2 O3, as an example, could be efficient for sulfosalicylic acid oxidation, reaching comparable faraday efficiency of sulfosalicylic acid to that of the boron-doped diamond electrode. Ti-doped electrodes exhibited both higher removal rates and current efficiency compared to the undoped. This could be mainly ascribed to the enhanced charge transfer rate constant. Kinetic analysis shows that the apparent reaction order, in terms of sulfosalicylic acid in bulk solution, depended on applied potential and pollutant concentration. Mechanism study shows that the oxidation of sulfosalicylic acid was mainly through indirect pathway. Moreover, the oxidation products were determined and the oxidation mechanism was proposed. This study may open a door to employ base-metal oxide semiconductor anodes for the efficient treatment of organic wastewater. Graphical abstract: Image 1 Highlights: Ti doped α -Fe2 O3 semiconductor electrodes are efficient for PPCP treatment. The oxidation of sulfosalicylic acid is mainly through indirect pathway. Adjusting Ti doping levels could accelerate the charge transfer kinetics.