Publisher: Chemical Society of Nigeria

Study of The Effect of Ph and Supporting Electrolytes On Permeation of Ions, Through A Polymeric Membrane

B. N Okolue, C. I. Ekeocha, B. I. Ikeaka
KEYWORDS: Membranes, Fick’s law, solubility diffusion model, diffusion coefficient, permeation, conductometric technique, pH and supporting electrolyte.


Despite intense studies over years, the mechanism behind the movement of water and other small nanoelectrolyte through membranes remains unclear. Previous Researchers had focused on some factors affecting this movement like nature of membrane, permeation time, concentration of electrolyte samples, ionic size, etc. It is on this basis that we conducted a research on the effect of pH and supporting electrolytes on permeation of ions through a polymeric membrane using conductometric technique at 25'C .The results obtained from the study shows that diffusion rate of various electrolyte samples increases gradually with increase in time. Also on addition of supporting electrolyte, there was a rapid increment in the diffusion rate. This was as a result of increment in the concentration of the counter ions (cations) which were attracted to the membrane matrix while the chloride ions are excluded from the membrane phase. However, there was a drop in the rate of permeation of ions at pH of 4 which could be attributed to the interference of the hydrogen ion [H+] with the electrolyte solution and thus retarding the rate of permeation. Nevertheless, a slight increment was observed in an alkaline medium on pH 11. The diffusion trend can be said to follow the pattern of Al3+<Ca2+<Na+. The permeation flux calculated using the derived Fick’s law shows good agreement with the experimental values. Thus these factors and others should be considered in the use of membranes for scientific work like in ultra filtration, water purification, reverse osmosis, nanofiltration, microfiltration etc.

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