Electrolytic production of HCI and KOH using ion exchange membranes

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University of Dar es Salaam
The behaviour of a caution and an anion selective membrane in close contact was investigated. The double membranesyst4m were characterized under dynamic conditions. Concentration polarization on the double membrane system was found to be a function of current density though the system and depended on the amount of stirring of the solution bounding the membrane system. Current voltage characteristic of the double membrane separating HCL and KOH solutions showed a strong non-linear relationship. Similar relationship was obtained when membrane separations was increased to 0.1 cm. The possibility of producing a base and on acid from a salt and water in five compartments cell, separated by ion selective membranes was investigated. The following total reaction was found to occur. KCL +H20 = HCL + KOH. The acid and base produced were separated and analysed and the current efficiency of the membrane system established Efficiency as high as 97% was obtained. The efficiency was found to be dependent on membrane thickness and concentration of the bonding KCL solution. It was found however to be independent of current density as long as the system was under steady state conditions. Some analytical data on transport of anions OH and Cl across cation selective membrane and transport of cationsHr and Kr across anion selective membrane were obtained. The ion selectivity of the anion membrane was found to be slightly poor in comparison to that the caption membrane. The investigation though in laboratory scale indicate that the process may have advantages compared to other processes commonly used when the need is for an acid and base and where the usual by products of alkali electrolysis, H2 and C2 gases are not in demand. A theoretical treatment of the opposite reaction namely HCL + KOH = KCL + H20 is provided whereby it is pointed out that application of the above process would serve as a storage of electrical energy.
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Electrolysis, Oxidation, Electrolytic, Electrochemical analysis
Makange, A. A (1975) Electrolytic production of HCI and KOH using ion exchange membranes, Masters dissertation, University of Dar es Salaam. Available at ( )