Hco3–cl Equilibrium On Strongly–basic Anionites
HCO3–Cl Equilibrium on Strongly–Basic Anionites
O. S. Mokraya, O. V. Mamchenko
Institute of Colloid and Water Chemistry of the Ukrainian National Academy of Sciences, Kiev, Ukraine
HCO3–Cl exchange equilibrium on strongly–basic ionites of type I (AB-17-8) and type II (Lewetit MP 600) has been studied by us experimentally. An attempt of its quantitative interpretation has been made on the base of exchange equilibrium theory. A strong dependence of apparent exchange constant of bicarbonate- and chloride-ions on strongly–basic ionites from resinate composition has been determined, that is connected with big differences between local equilibrium constants for different composition of gegenion in near environment. Thus, on appearing in the near environment of one chloroion a local constant increases by order greater; on appearing of two chloroions a local constant increases by two orders greater. These effects may be observed in the same degree for the strongly-basic ionites AB–17-8 and Lewatit MP–600. A possible reason of strong dependence of local equilibrium constants on chloroions content in near environment is the effect of bicarbonate-ions \’\'outsalting\’\’ from gel phase that is similar to the observed in concentrated solutions olf two salts with different dissolubility. As the resinate solution has high concentration, the injection of a well dissoluble chloroion into it substantially decreases bicarbonate-ion dissolubility that is accompanied by displacement of the latter into the outer solution and ionite encreasing selectivity to chloroiones. The found dependence of an appearent equilibrium constant on the transition degree of strongly-dependent ionite into chlor form testifies to the possibility of practically total displacement of bicarbonate-iones by aniones of strong acids from anionite layer that allows to use the new technology according to which the water influenced by anionite undergoes H-ionising on carboxyl cationite that absorbs cations only which are connected with the anions of weak acids.
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