Mg. Kolpachnikova et al., Effect of temperature on retention of alkali and alkaline-earth metal ionson some aminocarboxylic acid functionalised silica based ion exchangers, J CHROMAT A, 826(1), 1998, pp. 15-23
The temperature effect on retention of alkali and alkaline earth cations on
three different carboxylic acid cation exchangers was investigated. The si
lica-bonded 2,6-diaminohexanoic (lysine), 2-aminoglutaric (glutamic acid) a
nd iminodiacetic acids were used as cation exchangers and compared with har
e silica. Perchloric acid was used as the eluent in all experiments. The de
pendence of retention (log k') from reciprocal temperature (1/T) is linear
for all cations in the case of silica-bound lysine and glutamic acid. An ab
normal parabolic dependence of log k' vs 1/T was observed for iminodiacetic
acid functionalized silica. The possible impact of complexation between fu
nctional groups of cation exchangers and retained cations and the effect of
two carboxylic groups in a single ion-exchange site on retention are discu
ssed. The calculated values of heats of adsorption are in the range 4-9 kJ/
mol. (C) 1998 Published by Elsevier Science B.V. All rights reserved.