Abstract: The adsorption isotherms of tetradecylpyridinium chloride (TPC) from aqueous solutions on the zeolite 5A and the influence of pH, inorganic salts upon the.adsorption of TPC have been studied (at 25℃). The electrophoretic mobilities of zeolite 5A in the same systems have also been measured. The results show that (1) The adsorption of TPC is independent of the pH in the range of 6—11, which is explained by the constant value of electrophoretic mobilities; (2) The Langmuir type isotherms turn into the S type with the increasing concentration of inorganic salts; (3) The surface of the zeolite 5A particle is negatively charged in water. After adding Al³⁺, the surface charge reverses its sign and the adsorption of TPC decreases markedly.

Key words: Adsorption, Adsorption from solutions, Zeolite