2. Experimental
2.1. Materials and methods
2.1.1. Reagents and Clay samples Orthophenylphenol (CAS no. 90-43-7) and monuron (CAS no.
150-68-5) were obtained from Aldrich (Milwaukee, WI), with purity (>98%). They were used without any further purification. The chemical structures of these pesticides are given in Fig. 1. The mineral used as a model adsorbent was K-montmorillonite (K-M), purchased from Fluka chemistry AG. Fe(III)- montmorillonite (Fe-M) and HA-montmorillonite (HA-M) were prepared by adsorption using the method developed by Cox and Koskinen (1998). Clay minerals composition were
analyzed by X-ray fluorescence using AXIOS-P analytical equipment. The chemical composition of clay fractions is summarized in Table 1.