The area of zeolites' application could be expanded by utilizing their surfaces. Zeolites are frequently modified to increase their hydrophobicity and to generate the negative charge of the surface. The main objective of the study was to investigate and compare the features of natural clinoptilolite and synthetic zeolite Na-P1 modified by selected surfactants involving quaternary ammonium salts. The FTIR study indicates that with increasing carbon chain length in the surfactant attached to the zeolites surface the molecules adopt a more disordered structure. FTIR was also used to determine the efficiency of surface modification. Thermal analysis revealed that the presence of surfactant results in additional exothermic effects associated with the breaking of electrostatic bonds between zeolites and surfactants. The mass losses are in line with ECEC and CHN data. The textural study indicates that the synthetic zeolite Na-P1 has better sorption properties than natural clinoptilolite. The modification process always reduces the S-BET and porosity of the material. With an increasing carbon chain length of surfactants all the texture parameters decrease. (C) 2015 Elsevier B.V. All rights reserved.