This study has evaluated chemical, radiological composition and determined the cation exchange capacity (CEC) for three commercially available Brazilians raw kaolins. The mineralogical characterization indicated the presence of kaolinite, kaolinite and quartz and pirophylliteas the mains mineral constitution of the samples. The results of the adsorption study indicated that the three samples did not show a significant increase in CEC due to acid or thermal treatments. However, the sample that presented the highest kaolinite content and CEC showed an effective cost benefit for water treatment application with low energy and chemical reagents spending.