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Please cite this article in press as: P.A. Prashanth, et al., Synthesis, characterizations, antibacterial and photoluminescence studies of solution combustion-derived ␣-Al 2 O 3 nanoparticles, J. Asian Ceram. Soc. (2015), http://dx. a b s t r a c tIn this work, we report a novel, economical, low temperature solution combustion synthesis (SCS) method to prepare ␣-Al 2 O 3 (Corundum) nanoparticles. Powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), BET surface area and ultraviolet visible spectroscopy (UV-vis) measurements were used to characterize the product. Antibacterial studies were examined against gram −ve Klebsiella aerogenes, Escherichia coli, Pseudomonas desmolyticum and gram +ve Staphylococcus aureus bacteria by agar well diffusion method. The ␣-Al 2 O 3 nanoparticles showed substantial effect on all the four bacterial strains. Photoluminescence (PL) measurements under excitation at about 255 nm show that the alumina nanoparticles have emission peaks at 394 and 392 nm.

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Nanocrystalline meta-zinc titanate (ZnTiO 3 ) ceramic was prepared using a self-propagating solution combustion synthesis (SCS) for the first time using urea as fuel. The product was calcined at 800 • C for 2 h to improve the crystallinity. Powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX), high resolution transmission electron microscopy (HR-TEM) and UV-vis absorption spectroscopy were used to characterize the final product. PXRD results show that the ilmenite type rhombohedral structure was formed when the sample was calcined at 800 • C for 2 h. Adsorption experiments were performed with cationic malachite green (MG) dye. ∼96% dye was adsorbed onto nanocrystalline ZnTiO 3 ceramic at pH 9 for 30 min of the contact time. The optimum adsorbent dose was found to be 0.45 g/L of dye. Langmuir-Hinshelwood model was used to study adsorption kinetics and first order kinetic model best describes the MG adsorption on ZnTiO 3 . Antibacterial activity was investigated against gram negative Klebsiella aerogenes, Pseudomonas desmolyticum, Escherichia coli, and gram positive Staphylococcus aureus bacteria by agar well diffusion method. Nanocrystalline ZnTiO 3 ceramic showed significant effect on all the four bacterial strains at the concentration of 1000 and 1500 g per well.

In this article we report on solution combustion method to synthesize SrTiO 3 nanoparticles (ST-NPs) and the removal of malachite green (MG) azo dye from the aqueous solution. The synthesized ST-NPs were calcined at 600 • C for 2 h. Powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) were used to characterize the product. Adsorption experiments were performed with cationic malachite green (MG) dye. ∼98% dye was adsorbed onto the ST-NPs at pH 10 for 30 min of the contact time. The optimum adsorbent dose was found to be 0.015 g/L of the dye. To study the adsorption kinetics Langmuir Hinshelwood model was used and the first order kinetic best describes the MG adsorption onto the ST-NPs. The adsorption isotherms data of MG onto ST-NPs obtained were analyzed by Langmuir and Freundlich isotherm models and the results describe the best representation of the Langmuir isotherm model.

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In this work, reduced graphene oxide-nickel (RGO–Ni) nanocomposite is synthesized. X-ray diffraction (XRD), scanning electron microscopy (SEM) and SEM–EDS (Energy Dispersive X-Ray Spectroscopy) are used to study the crystalline nature, morphology and elemental composition of the RGO–Ni nanocomposite, respectively. As synthesized RGO–Ni nanocomposite is used to develop selective adsorptive removal of Rhodamine B (RhB) dye from the aqueous solution. The experiments have been performed to investigate RhB uptake via RGO–Ni nanocomposites which include, contact time (60 min), initial dye concentration (50 mg/100 ml), adsorbent dosage (0.5 mg) and pH 8 of dye solution. The equilibrium concentration is determined by using different models namely, Freundlich, Langmuir and Tempkin. Langmuir isotherm has been fitted well. Langmuir and Tempkin equations are determined to have good agreement with the correlation coefficient data. The kinetic study concluded that RhB dye adsorption follows with the pseudo-second-order kinetic model. Further, adsorption mechanism of RGO–Ni is proposed which involves three steps. The synthesized adsorbent is compared with the other adsorbents in the literature and indicates that RGO–Ni nanocomposite used in this study shown better results for a particular adsorption capacity than polymeric, natural and synthetic bioadsorbents. The regeneration and reusability experiments suggest RGO–Ni nanocomposite can be used for many numbers of times for purification/adsorption.

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