Effect of the Al/clay ratio on the thiabendazol removal by aluminum pillared clays

In this work, four aluminum pillared clays (Al-PILC) with different Al/clay ratios were synthesized and evaluated for the removal of thiabendazole (TB) (a fungicide widely used in agricultural activities) from aqueous media. The Al-PILC were thoroughly characterized by different techniques, such as X-ray diffraction (XRD), thermogravimetric analysis (DTA-TG), adsorption-desorption of N-2 at 77 K, NH3-temperature programmed desorption (NH3-TPD) and transmission electron microscopy (TEM). The TB-adsorption studies were carried out in batch, at room temperature, at pH = 6 (natural pH, without additional control) and with different concentrations of TB (2-100 ppm). The measured TB adsorption capacities varied from 11.78 to 17.50 mg TB per gram of clay. The TB-Al PILC complexes obtained after the adsorption process were studied by X-ray photoelectron spectroscopy (XPS). The results suggested that the molecules of TB were adsorbed on the Al-PILC by two different phenomena: by physisorption in their porous structure and by chemisorption on their pillars, showing a concordance between the amounts of incorporated aluminum in the pillared clays and their fungicide adsorption capacity. (C) 2013 Elsevier B.V. All rights reserved.