The aim of this study is to determine the adsorption properties of microwave synthesized inorgano-organo montmorillonites. Microwave irradiation is preferred because of its low time and energy consumption properties. forming an advantage in industrial applications. In addition to the intercalation of Keggin and hexadecyltrimethylammonium (HDTMA(+)) cations, the aging process of pillaring solution was also carried out through the microwave irradiation. Both inorgan clays, namely the parents, and their inorgano-organo derivatives, were prepared by using the same amounts of aluminum by keeping the OH-/Al3+ and Al3+/clay ratios constant. The HDTMA(+)/clay ratio was changed in inorgano-organo clays (IOCs) during the preparation. The effects of these parameters on the surface properties and adsorption behaviors of the samples were investigated by conducting X-ray diffraction (XRD). Fourier transform infrared (FTIR) and simultaneous thermal analyses (STA), as well as hatch adsorption experiments. in which phenol was used as a model pollutant. The results of XRD analyses reveal that the intercalation is successfully achieved. The existence of the Keggin and HDTMA(+) cations was observed in FTIR spectra of the samples. Through the STA. it was determined that the existence of organic layer increases the dehydroxylation temperature and the thermal behavior of inorgano-organo montmorillonites strongly depends on the structure of the parent clay. An increase in the adsorption efficiencies with increasing HDTMA(+)/clay ratio was observed, except with the highest ratio. The behavior of this sample was explained by the formation of the second HDTMA(+) layer leading to the hydrophilic surface formation. (C) 2009 Curtin University of Technology and John Wiley & Sons, Ltd.