Liquid absorbing acidic gases and use thereof in diacidification of gases

A process for improved CO.sub.2 absorption from a gas by an absorbent liquid which has an improved absorption capacity for CO.sub.2 which process comprises contacting said gas and the absorbent liquid in an absorption zone having an upper and lower part, thereby obtaining a treated gas with a reduced content of CO.sub.2 and the absorbent liquid with increased CO.sub.2 content, and regenerating the absorbent liquid which has an increased CO.sub.2 content, thereby releasing the CO.sub.2 and producing at least one gaseous fraction containing the released CO.sub.2 and at least one portion of the regenerated absorbent liquid and recycling said regenerated absorbent liquid to the absorption zone, the absorbent liquid being a mixture of one or more tertiary alkanolamines and an activator of improved CO.sub.2 absorption by said tertiary alkanolamines, the activator having the general formula

• Y--(C.sub.p H.sub.2p)--NHZ
• wherein Y is a monovalent radical selected from the group consisting of piperazyl, piperidinyl, furyl, tetrahydrofuryl, thienyl, tetrahydrothienyl and --OR.sub.2 radicals, Z is an --R.sub.2 radical or hydrogen, R.sub.2 is a monovalent hydrocarbon residue, and p is an integer from 1 to 6.