Rising atmospheric CO\(_2\) levels and increasing emissions from internal combustion (IC) engines highlight the need for compact carbon-capture technologies suitable for distributed emission sources. This study presents a simulation-based analysis of an electrochemical CO\(_2\) absorption system for engine exhaust using an aqueous NaCl electrolyte. A dynamic MATLAB/Simulink model is developed by coupling gas–liquid mass transfer, Henry’s-law solubility, simplified electrochemical kinetics, Faraday-based hydroxide generation, and pH-dependent carbonate/bicarbonate speciation. Under the corrected baseline conditions of \(60~\mathrm {L \times min^{-1}}\) exhaust flow containing \(12~{vol\%}\) CO\(_2\), the system captures \(69.38~\textrm{g}\) CO\(_2\) over a \(1~\textrm{h}\) operating period, corresponding to a cycle-integrated capture efficiency of \(8.93\%\). At the simulated bulk pH of approximately \(8.8{-}9.0\), bicarbonate formation is dominant; therefore, the effective electron requirement is treated as \(n_{\textrm{eff}}\approx 1\) rather than assuming complete carbonate formation. Using a representative Faradaic efficiency of \(85\%\), the current required to support the corrected capture rate is \(49.7~\textrm{A}\), giving a corrected cell-level specific energy consumption of \(2.72~\mathrm {kWh \times kg^{-1}_{CO_2}}\). When first-order auxiliary loads for gas handling, cooling, electrolyte circulation, and control electronics are included, the estimated system-level energy requirement increases to approximately \(4.24~\mathrm {kWh \times kg^{-1}_{CO_2}}\). Sensitivity and optimization analyses indicate that mass-transfer performance, electrode area, electrolyte concentration, Faradaic efficiency, and auxiliary power demand strongly influence overall system performance. Because the model is not experimentally validated, the results should be interpreted as a preliminary feasibility and sensitivity assessment rather than a definitive prediction of reactor performance. The Bangladesh case study is used only to illustrate potential deployment relevance for distributed exhaust sources, while experimental validation, improved electrode kinetics, chloride-management strategies, and detailed techno-economic assessment are identified as essential future work.
