ORIGINAL PAPER Kinetic and mechanistic study of p-nitrochlorobenzene photoreduction and Bacillus inactivation over aluminosilicate-based nanocomposites Mohsen Padervand • Hadi Salari • Faramarz Sadeghzadeh Darabi • Mohammad Reza Gholami Received: 16 March 2012 / Accepted: 24 August 2012 / Published online: 2 October 2012 Ó Springer-Verlag 2012 Abstract Photocatalytic reduction of p-nitrochloroben- zene was studied over aluminosilicate-based AgBr and AgBr-TiO 2 photocatalysts which were prepared and char- acterized. The photoreaction was performed in the presence of LiBH 4 , which is a strong reducing agent, in the solution medium. A new mechanism is proposed for reduction of p-nitrochlorobenzene under photocatalytic conditions. The effect of pH, illumination source, LiBH 4 concentration, temperature, catalyst dosage, and alcoholic scavengers was also studied. The results showed that the best efficiency was obtained over Ag/AgBr/TiO 2 /aluminosilicates at nat- ural pH under UV light. We observed that the reaction yield was affected by changing the LiBH 4 concentration and temperature, while the effect of former case was more considerable. In addition, it was found that methanol as a hole scavenger has the strongest effect on increasing the photoreduction efficiency. Also, the results for inactivation of Bacillus bacterium indicated that AgBr-modified photo- catalysts had the best antibacterial activity, whereas the pure aluminosilicates and TiO 2 /aluminosilicates did not show any antibacterial activity under visible light and dark conditions. Keywords Aluminosilicates  p-Nitrochlorobenzene  LiBH 4  Photoreduction  Bacillus Introduction Heterogeneous catalysts, particularly porous materials such as alumina, silica, and zeolites, have many advantages as supports because of their high surface area, shape/size selectivity, and easy separation from reaction mixtures. Mesoporous structures would seem to be ideal for forming a scaffold in which 3-dimensional dispersions of metal nanoparticles could be supported. Zeolites represent an especially attractive class among the transition-metal-free catalysts for hydrogenation reac- tions, owing to the existence of a large variety of natural/ synthetic zeolites having a wide range of acid/base prop- erties [1, 2]. Zeolite catalysis and photocatalysis generally includes acid-catalyzed reactions, with many industrial applications in petroleum refining and petrochemical pro- duction. However, a number of base-catalyzed zeolite processes have also been reported [3]. Owing to its physical properties such as resistance to radiation, mechanical stress, and heat as well as its low cost, availability, and high stability, TiO 2 is considered one of the most promising photocatalysts for environmental cleanup, e.g., the degradation of pollutants [4–10]. TiO 2 - coated composites practically used thus far have been provided with self-cleaning, antibacterial, and/or anti-fog- ging functions based on the photoinduced decomposition reaction and photoinduced hydrophilicity [11]. Recently, hydrogenation of nitrates on surface-modified TiO 2 -based catalysts has been reported [12]. Titanium dioxide solely or as binary oxides of TiO 2 /SiO 2 has been considered as a potential support for hydrogenation reactions [13–15]. Because of the wide band gap of TiO 2 (3.0–3.2 eV), it is active only under near-ultraviolet irradiation. Numerous workers have researched methods to modify TiO 2 to make it photoactive under visible light [11, 14]. M. Padervand (&)  M. R. Gholami Department of Chemistry, Sharif University of Technology, Azadi Avenue, P.O. Box 11365-9516, Tehran, Iran e-mail: padervand@mehr.sharif.ir H. Salari  F. S. Darabi Young Researchers Club, Parsabad Mogan Branch, Islamic Azad University, Parsabad, Iran 123 Monatsh Chem (2013) 144:589–596 DOI 10.1007/s00706-012-0853-y