Sorption of phosphatidylcholine onto highly ordered mesoporous materials under static conditions

Abstract

Some features of equilibrium sorption of phosphatidylcholine onto MCM-41 type mesoporous materials are presented in this paper. The experimental results are processed using mathematical equations of Langmuir and BET models for equilibrium sorption phospholipid on highly ordered mesoporous materials.
It is shown that the structure order, the value of specific surface area of the sorbents leads crutial role on the form of equilibrium curve of adsorption. Isotherms of phosphatidylcholine adsorption onto ordered mesoporous siliceous materials are characterized by monolayer adsorption at the lower final solution concentration range and the second stage at the equilibrium concentration of phosphatidylcholine > 4.5 mmol / dm3 corresponds to multilayer adsorption in the mesopores. Mathematical equations of Langmuir and BET models of sorption were used for determination of equilibrium parameters of process (maximum adsorption capacity of the monolayer, and constants characterizing interactions between sorbent-sorbate, and sorbate-sorbate). It is found that at the formation of phosphatidylcholine monolayer is due to hydrogen bonding of silanol groups of sorbent with oxygen atoms phosphoric group of phosphatidylcholine whereas the formation of multilayers is caused by the association of the phosphatidylcholine molecules .