Adsorption of isoproturon on homoionic clays

The adsorption of isoproturon (3-(4-isopropylphenyl)- 1,1 dimethylurea)] on a montmorillonite and on a kaolinite was studied by batch experiments and Fourier transform infrared spectroscopy (FT-IR). The clays were saturated with cations such as Al3+, Ca2+, Cu2+, Na+ and hexadecyl-trimethylammonium (HDTMA). The studied clays did not show detectable catalytic activity on abiotic degradation of isoproturon, as evidenced by HPLC analysis. Adsorption was found related to clay specific external surface for HDTMA-saturated clays, while it seems independent from clay kind and inorganic cation. For clays saturated with inorganic cations, no penetration into the mont-morillonite interlayer was found and FT-IR spectroscopy showed the involvement of C=O group of isoproturon in adsorption.