Citation

Rahman, Md Sadman A. and Rejuan, Allama and Hossain, Shah Mohazzem and Al Qwaid, Marran and Abdul Karim, Hezerul and Sarker, Md Tanjil (2026) Electrochemical CO2 capture from engine exhaust using NaCl electrolyte: System modeling, optimization, and economic assessment. Scientific Reports, 16 (1). ISSN 2045-2322

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Abstract

Rising atmospheric CO2 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 CO2 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 L × min−1 exhaust flow containing 12 vol% CO2, the system captures 69.38 g CO2 over a 1 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 neff ≈ 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 A, giving a corrected cell-level specific energy consumption of 2.72 kWh × kg−1 CO2 . 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 kWh × kg−1 CO2 . 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.

Item Type:	Article
Uncontrolled Keywords:	CO2, capture, Electrochemical absorption
Subjects:	T Technology > TP Chemical technology > TP155-156 Chemical engineering
Divisions:	Faculty of Artificial Intelligence & Engineering (FAIE)
Depositing User:	Ms Rosnani Abd Wahab
Date Deposited:	30 Oct 2026 07:23
Last Modified:	30 Oct 2026 07:23
URII:	http://shdl.mmu.edu.my/id/eprint/17056

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