Novel solvents and methods of use for the removal of CO2 from flue gas, natural gas, hydrogen gas, synthesis gas, and other process and waste gas streams are provided. The solvent contains an alkali salt such as potassium carbonate and a polyamine such as piperazine (PZ) where the polyamine concentration is at least 1.5 equivalents/Kg H2O and the alkali salt concentration is at least 0.5 equivalents/Kg H2O. The preferred alkali salt/polyamine ratio is from approximately 1:2 to 2:1, and no additional alcohol is required for solubilizing the PZ. This chemical solvent and method of use provides efficient and effective removal of CO2 from gaseous streams and other sources.