SELECTIVE UPHILL TRANSPORT OF CYANIDE ION-MEDIATED BY TETRAPHENYLPORPHINATOMANGANESE (III) COMPLEX THROUGH BULK AND POLYMER-SUPPORTED LIQUID MEMBRANES

The present paper describes the results obtained in a new system for hydroxide ion coupled transport of cyanide ion (uphill transport). The uphill transport was observed in two liquid membranes containing a tetraphenylporphinatomanganese(III) complex carrier (Mn(III)TPP). One is a bulk liquid membrane (BLM) that consists of a dichloromethane solution. The other is a polymer-supported liquid membrane (SLM) that was prepared by submerging a thin microporous polypropylene film in an o-nitrophenyl n-octyl ether solution. The OH ligand of the complex Mn(III)TPP (OH) is easily substituted with cyanide ion. The equilibrium constant of the reaction with cyanide ion is much larger than those with halide ions, CH3COO-, and NO3-. Only cyanide ion was transported selectively in the presence of various anions (CN-, Cl-, F-, NO3-, CH3COO-, etc.). We applied simple models to the uphill transport. In the BLM system, the flux of cyanide ion is governed by the diffusion processes of cyanide ion and the carrier molecule in the stagnant layers. The thicknesses of the layers and the ligand substitution reaction rate constants were estimated. In the SLM system, the flux of cyanide ion is controlled by the diffusion process of the carrier molecule obeying the Stokes-Einstein model in the membrane phase.