Sunmi Im  Yiseul Park

Vol. 29,  No. 1, pp. 46-52, Mar.  2023
10.7464/ksct.2023.29.1.46

Zinc oxalate Glycolic acid Electrochemical conversion

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Oxalic acid has been traditionally obtained via the oxidation of carbohydrates using nitric acid and catalysts. However, this process produces a variety of nitrogen oxides during oxidation and requires a separation process due to its various intermediates. These products and additional steps increase the harmfulness and complexity of the process. Recently, the electrochemical reduction of carbon dioxide into oxalic acid has been suggested as an environmentally friendly and efficient technology for the production of oxalic acid. In this electrochemical conversion system, zinc oxalate (ZnC2O4) is obtained by the reaction of Zn2+ ions produced by Zn oxidation and oxalate ions produced by CO2 reduction. ZnC2O4 can then be converted to form oxalic acid, but this requires the use of a strong acid and heat. In this study, a system was proposed that can easily convert ZnC2O4 to oxalic acid without the use of a strong acid while also allowing for easy separation. In addition, this proposed system can also further convert the products into glycolic acid which is a high-value-added chemical. ZnC2O4 was effectively separated into Zn(OH)2 powder and oxalate solution through a chemical treatment and a vacuum filtration process. Then the Zn(OH)2 and oxalate were electrochemically converted to zinc and glycolic acid, respectively.