TRANSPORT OF Cr³⁺, Cd²⁺, Pb²⁺, AND Ag⁺ IONS THROUGH BULK LIQUID MEMBRANE CONTAINING p-tert-BUTYLCALIX[4]ARENE –TETRACARBOXYLIC ACID AS ION CARRIER

The research on transport of Cr, Cd, Pb, and Ag through bulk liquid membrane using p-tertbutylcalix[4]arene-tetracarboxylic acid as ions carrier has been conducted. The aims of this research were to determine optimum condition, efficiency, and selectivity of transport of the ions carriers to those ions. Both optimum condition and efficiency of transport were obtained by determination of transported ions concentration with pH variation of source phase, ionic carrier concentration, nature of stripping agent in target phase, and transport time. The transport selectivity of ions carrier was obtained from experiments of equimolar mixture ions transport competition. Amount of Cr, Pb, Cd, and Ag transported across liquid membrane were about 6, 80, 84 and 87 % respectively after being transported for 48 h. The ion carrier was selective for both Pb ion (separation factors are 9.6 for Ag ion, 1.9 for Cd ion and infinite for Cr ion) and Ag ion (separation factors are 1.8 for Cd and infinite for both Pb and Cr ions). This system represents a proton-coupled transport with flow of protons in the opposite direction.