Abstract

This research outlines a four-step methodology for transforming CO2 into high-purity oxalic acid. CO2 was first sequestered as KHCO3 through its reaction with aqueous KOH, followed by hydrogenation using a supported AgPd/CNT catalyst in a batch reactor at an initial H2 pressure of 60 bar and a temperature of 150°C. The formate yield reached 91.8% at optimum conditions. Potassium formate in the solid state was thermally coupled in the presence of KOH at 400°C under N2 flow, yielding potassium oxalate of up to 76% yield. The final step was the selective precipitation of potassium oxalate with ferrous ions to produce FeC2O4·2H2O, with approximately 99% recovery efficiency, and then ferrous oxalate was acidified with HCl to get crystalline oxalic acid (H2C2O4·2H2O) with a yield of about 85% with a product purity of 99%. After integrating all four steps, the overall yield of oxalic acid from CO2 was about 57%.

Department(s)

Civil, Architectural and Environmental Engineering

Second Department

Chemical and Biochemical Engineering

Publication Status

Full Access

Keywords and Phrases

AgPd/CNT catalyst; catalytic hydrogenation; CO2 conversion; oxalic acid synthesis; potassium oxalate; thermal coupling reaction

International Standard Serial Number (ISSN)

1547-5905; 0001-1541

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Wiley; American Institute of Chemical Engineers (AIChE), All rights reserved.

Publication Date

01 Jan 2026

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