Experiments and theory for the surface tensions of carbonated MDEA–PZ aqueous solutions

Surface tensions of carbonated N-methyldiethanolamine (MDEA)–piperazine (PZ) aqueous solutions were measured at the temperatures ranging from 293.15 to 323.15 K. A theoretical model was proposed to correlate the surface tensions and the calculated results agreed well with the experiments. The residual MDEA and PZ in the carbonated aqueous solutions were determined on the basic of ‘shuttle’ mechanism. The temperature, amine concentration and CO2 loading (α, mole number of CO2/mole number of MDEA + PZ) dependences of the surface tensions were demonstrated.

► The surface tensions of carbonated MDEA–PZ aqueous solutions were measured.
► A theoretical model that can accurately describe the surface tensions was proposed.
► The residual amines and the composition were determined by using the shuttle mechanism.
► The influences of temperature, amine concentration and CO2 loading were demonstrated.