Clay is a very abundant raw material in Madagascar. There are several types of clay dependingon their color. Our study focuses on the modification of white and green clays by grafting TiO2 onto the outer surface and analyzes of specific surfaces of raw and modified clays. Raw white clay has a small specific surface area compared to green clay. When TiO2 is fixed to the surface, there is a marked decrease in pore size and an increase in the surface for white clay, while for green clay there is no change since pore size has not changed, TiO2 is fixed to nanometric clay particles. The active surface area and pore structure of catalysts influence production rates. Limiting the pore size allows only molecules of desired sizes to enter and exit, creating a selective catalyst that will produce primarily the desired product. I would like to thank the laboratory team of the Molecular Chemistry and Solid Organization (MCSO) Unit of the University of Montpellier II France for the analysis of the samples

Abstract The objective of this study to show that TiO2 can be attached to the external surface of clays. Two types of clay, white and green clay, have been used because those raw materials are very abundant in Madagascar. The composite material is useful to eliminate pathogenic microorganism and decompose organic compounds in polluted water, for example. The BET (Brunauer, Elmett and Teller) analysis is the best method to evaluate the capacity of the composite to catalyze the reaction of decomposition. The BET analysis of specific area are 60.71 m2/g for white clay (micropore surface 9.63 m2/g and outer surface 51.08 m2/g with pore size 151.46 Å, an A° = 1millionth of a millimeter) and 249.52 m2/g for green clay (micropore area 20.51 m2/g and outer surface 229.01 m2/g with pore size 49.96 Å). The size of the micropores is less than 17 Å. When TiO2-clays are treated at 600°C, the specific area of white clay increases, it becomes 94.07 m2/g while pore size decreases (81.39 Å). For green clay, the specific area is about the same (247.61 m2/g) and pore size doesn’t change (49.97 Å). Keywords: Clay, TiO2, Specific surface, Nanotechnology, Composite material