Green and Sustainable Carbon Dioxide Capture in Aqueous l‑Valine: Experimental Studies on Process Efficiency and Gas Uptake for Industrial Applications

The utilization of fossil fuels to satisfy our growing energy and nonenergy needs is resulting in a significant release of anthropogenic CO2 emissions. The capture of carbon dioxide (and its utilization and sequestration) plays a crucial role in the decarbonizing economy. In this study, we report the application of an aqueous amino acid (l-valine) as a sustainable green solution for CO2 capture at ambient temperature (298.15 K) and pressure of 1.3 Mpa. We studied the process of CO2 capture in a high-pressure setup equipped with a complete data acquisition system to monitor and record the pressure and temperature in real-time. Each experiment was done thrice to determine the saturation (carbon dioxide uptake capacity) along with the feasibility of designing a continuous process. Further, the samples were characterized by FTIR-ATR and UV spectroscopy to understand the mechanism of CO2 uptake and the formation of various reactive intermediates. Additionally, the experimental data were analyzed for the validation of gas uptake in the system by an exponential curve fitting model to study absorption as well as Langmuir and Freundlich isotherms for adsorption. To interpret the impact of mass transfer on CO2 uptake, a common surfactant, sodium dodecyl sulfate (SDS), in a small quantity was utilized, and the obtained results are reported.