SUSTAINABLE FORMIC ACID PRODUCTION FROM CO2: A LIFE CYCLE ASSESSMENT ANALYSIS

Formic acid (HCOOH) can be produced using CO2 via electrochemical reduction. This has the potential to mitigate increasing greenhouse gas emissions by utilizing captured CO2 from other processes. This paper presents a life cycle assessment of the electrochemical reduction of CO2 process to produce formic acid. A lab-scale conventional H-type cell is constructed with a Nafion 117 membrane. The electrodes are synthesized using drop-casting method with lead particles. The LCA is carried out based on ISO14040 standards using GaBi software. The LCA analysis consists of the goal and scope definition, inventory analysis, impact assessment and interpretation. To understand the overall environmental impacts, the energy and material flows into and out of the system are analyzed. The system boundary is set to be cradle-to-gate and the raw material extraction, transportation, membrane production, electrode production and cell operation are studied. The impact assessment methodology used to assess the environmental impacts is ReCiPe 1.08 Midpoint indicator. The environmental impacts were found to be 5.94 kg CO2 eq, 4.05 x 10-7 kg CFC-11, 5.94 kg 1,4 DB eq, 1.12 x10-2 kg SO2 eq and 0.418 x 10-4 kg 1,4-DB eq for the climate change, ozone depletion, human toxicity, terrestrial acidification and terrestrial ecotoxicity for 1 kg formic acid produced, respectively. Overall, the cell operation electricity and water in the electrolyte had the highest impact on climate change, human toxicity, acidification and ecotoxicity. The membrane and electrode in the cell had an insignificant impact on all the categories except the ozone layer depletion, where the membrane accounts for 83% of the impact. The findings from this study can help researchers, policy makers and industrial stakeholders make critical decisions regarding material selection and optimization to increase the sustainability of the process.