A novel method of copper-exchanged aluminum-pillared clay preparation for olive oil mill wastewater treatment

A novel method of preparing copper-exchanged aluminum-pillared montmorillonite has been developed. The process does not use water and is simpler to operate than the conventional method of doping [K. Bahranowski, M. Gasior, A. Kielski, J. Podobinski, E.M. Serwicka, L.A. Vartikian, K. Wodnicka, Clay Miner. 34 (1999) 79–87. [1]; W. Najjar, L. Chirchi, E. Santosb, A. Ghorhel, J. Environ. Monit., 3 (2001) 697–701. [2]]. Here, catalysts containing different ratios of Cu/clay were prepared by solid-state reaction of the Al-pillared clay already synthesized with copper nitrate in controlled atmosphere. The resultant materials are characterized by X-ray diffraction, nitrogen sorption, chemical analysis, temperature-programmed reduction (TPR), and UV–visible diffuse reflectance spectroscopy. The properties of copper-based catalysts have been studied in the wet hydrogen peroxide photocatalytic oxidation (WHPPCO) (H2O2 with UV light) of real olive oil milling wastewater (OMW). For solution containing 0.5 g L−1 of catalyst, 2.2% H2O2 (V/V), and UV, results showed that after 2 h reaction, important concentration of polyphenols were removed with a significant total organic carbon (TOC) removal.