Kinetics of CO₂ Absorption into Aqueous Basic Amino Acid Salt: Potassium Salt of Lysine Solution

Abstract

Aqueous amino acid salts are considered as an attractive alternative to alkanolamine solvents (e.g., MEA) for carbon dioxide (CO2) absorption. The kinetics of CO2 into unloaded aqueous solutions of potassium lysinate (LysK) was studied using a wetted wall column at concentrations ranging from 0.25 to 2.0 M and temperatures from 298 to 333 K. Physicochemical properties of aqueous LysK solutions such as density, viscosity, and physical solubility of CO2 were measured to evaluate the reaction rate constants. The reaction pathway is described using zwitterion mechanism taking into account the effect of ionic strength on the reaction rate. Under the fast pseudo-first-order regime, the reaction rate parameters were obtained and correlated in a power-law reaction rate expression. LysK shows higher chemical reactivity toward CO2 than the industrial standard MEA and most of amino acid salts. Its reaction rate constants increase considerably with concentration and temperature. The reaction order is found to be an average value of 1.58 with respect to LysK. The forward second-order kinetic rate constant, k2 0 , are obtained as 31615 and 84822 m3 kmol−1 s−1 at 298 and 313 K, respectively with activation energy of 51.0 kJ mol−1. The contribution of water to the zwitterion deprotonation seems to be more significant than that of LysK for the above-mentioned kinetic conditions

VLE of Carbon Dioxide-Loaded Aqueous Potassium Salt of L-Histidine Solutions as a Green Solvent for Carbon Dioxide Capture: Experimental Data and Modelling

“…On the other hand, Figure 4 illustrates the behaviour of carbon dioxide loadings in 1 molar potassium salt of lysine (LysK) with 1 molar HisK solutions, whereas Figure 5 presents the behaviour of carbon dioxide loadings in 2.5 molar LysK and 2.5 molar HisK solutions. It can be seen Although amino acid salt of lysine was previously observed to have higher CO 2 absorption capacity than others in the group [7,9,[46][47][48], it is explicated in this study that amino acid salt of histidine o ered a comparable absorption capacity with the lysine. is can be attributed to the presence of an amide bond in the R-structure of L-histidine that presumably allows great capture of the carbon dioxide molecule.…”

Reaction kinetics of carbon dioxide with aqueous solutions of l-Arginine, Glycine & Sarcosine using the stopped flow technique

“…Amino acids have been commercially employed in acidic gas treatment processes, such as the BASF Alkazid solvent and the Giammarco-Vetrocoke (GV) process, which use carbonate solution as an absorbing solvent. Siemens Energy tested a commercial absorbent based on a functional amino acid salt solution in an industrial-scale pilot plant in Germany at 298 K and 313 K. Compared to MEA solution, the amino acid salt solution has near-zero fugitive emissions, less corrosion in equipment materials and very little oxygen degradation [5,6].Amino acid salts have drawn significant attention from researchers in the field of CO2 capture owing to their attractive characteristics [7][8][9][10][11][12][13][14][15]. Amino acids are known to have low volatility which results in low solvent losses during the regeneration process [16], substantial resistance to oxidative degradation, making them a suitable choice in the treatment of flue gases containing large amounts of oxygen.…”

Bio-inspired Systems for Carbon Dioxide Capture, Sequestration and Utilization

“…The main advantage of amino acid-based systems over conventional alkanolamines relies on high stability to oxidative degradation, high chemical reactivity with CO 2 , low vapour pressures (compatible with temperature of flue gases), and high surface tension (fundamental on the design of membranes). Various studies exist when an inorganic cation is used [6][7][8][9][10][11][12][13][14][15][16][17][18]. Here a selection will be emphasized to establish the structure of amino acid/CO 2 absorption-desorption properties relationship (Figure 4, Table 1).…”