Salts of the basic amino acid L-arginine are potential co-promoters and blending components for the conventional solvents used in carbon dioxide-based separations. This study defines the contribution of arginine salts to equilibrium carbon dioxide absorption at co-promoter concentrations (less than 1 M) and high pressure. Experimentally determined carbon dioxide loadings in aqueous potassium and sodium salt solutions of L-arginine show a positive relationship with pressure (range: 110�4110 kPa); but a negative behaviour with an increase in temperature (range: 303.15�363.15K) and solvents concentrations (range: 0.25�0.75 M). The experimental results are correlated by the Kent-Eisenberg and the explicit models, with an average absolute deviation of 10.72 and 5.03, respectively. The regressed parameters of both models allow satisfactory estimation of the carbon dioxide loadings in arginine salt solutions at other process conditions. Comparison with piperazine and monoethanolamine shows that L-arginine salts have a better carbon dioxide absorption capacity at high pressure. © 2020 Elsevier B.V.