Zeolites have been hydrothermally synthesized using Thai coal fly ash from Mae Mob Power Plant as silica and alumina sources. The synthesis conditions, i.e., SiO2/Al2O3 ratio, amount of water, amount of base, and aging temperature, were varied to prepare different topologies of zeolitic products. The zeolites attained were sodalite (SOD), gismondine (GIS), and cancrinite (CAN). The zeolites have been applied to adsorption of thiophene and benzotbiophene in n-hexane solution. It was found that GIS with higher specific surface area and average pore volume had superior performance to other synthesized materials. Adsorption capacity of our developed zeolites was compared to those of commercial zeolites, i.e. NaY, HUSY, beta, and ZSM-5 obtained via the conventional synthesis methods. The results suggested a potential of zeolites derived from Mae Moh coal fly ash for removal of refractory sulfur compounds, such as benzothiophene. (C) 2007 Elsevier Ltd. All rights reserved.