Transport of Ca2+ Ion through a Bubbling Pseudo-emulsion Liquid Membrane with Calixarenes and Calixcrowns as Carriers
Abstract
Several new calixcrowns were synthesized and characterized. The transport of Ca2+ ion was investigated through a bubbling pseudo-emulsion liquid membrane with these calixcrowns, the parent calix[n]arenes (n = 4, 6, 8) and the ester, acid derivatives of calix[4]arene as mobile carriers. The effects of the initial concentrations of Ca2+ ion in the source phase and the initial pH difference (ΔpH) between the receiving phase and the source phase were studied. The results suggest that there are two different transport mechanisms. The transports using calixarenes and their ester, acid derivatives as carriers represent a proton-coupled co-transport with a flow of protons in the opposite direction, while the transports using the calixcrowns as carriers exhibit the characteristics of an anion-coupled co-transport with a flow of anion in the same direction.