Exchange and Nonexchange Interactions during the Sorption of Histidine on Clinoptilolite and Glauconite

The patterns of sorption of histidine zwitterions by natural aluminosilicates—clinoptilolite and glauconite—have been established. The contribution of the exchange and nonexchange components of sorption to the sorption capacity of aluminosilicates has been determined. The sorption isotherm of histidine from dilute solutions has been described using the Langmuir theory. It was shown that monolayer fixation of the amino acid proceeds by the mechanism of ion exchange as a result of electrostatic interaction of NH_3^ + - histidine groups with electronegative centers of the sorbent framework. The formation of polymolecular layers as a result of association due to hydrogen bonds and dipole–dipole and hydrophobic interactions determines the nonexchange nature of sorption. The influence of the structure of aluminosilicates on their sorption parameters has been determined.