| Abstract: | Abstract This work deals with the study of the diffusion of Cl? ion through pure unblended polyvinylchloride (PVC) membranes of different thickness. Several PVC -tetrahydrofuran ratios and also different internal diameter glass disks have been used to change the thickness of the membrane. A chloride ion selective electrode also constructed in the laboratory is used as the detector. The electrode behaviour was studied by running up a calibration graph prior to membrane positioning. A mean slope of 57 ±1 mV/log.C at 28.0 ± 0.5 °C was obtained and the range of potential values were then known. The detector was very well washed and immediately a membrane was placed directly on its surface and assembled to a rotating disk electrode in order to get a diffusion cell. The receiving compartment in this system has a negligible volume. Therefore, the response of the chloride ion selective electrode is directly proportional to the flux of material through the membrane rather than to the receiving compartment concentration. An almost linear relationship between the Cl? ion concentration in the range 0.0010 – 0.10 M and its flux through the unblended PVC membrane was found. The chloride ion flux through the PVC membrane in solutions with the ion strength adjusted to 0.1 M was twice to that value obtained without ion strength adjustor (ISA) in the solution. Average rate transport in the range 3.5?10?7 to 9.6?10?7 mol/s Cl? was found at a rotation speed of 1280 rpm. |
