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.

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.

a b s t r a c tIn the present study, adsorption of methylene blue (MB) dye from aqueous solution on to a wild carrot flower activated carbon (WCFAC) as a potential adsorbent was investigated. No attempt has been made in the past on WCFAC and it also finds application in reducing the population of this poisonous weed. WCFAC was prepared using simple chemical activation method and MB dye adsorption was studied by batch adsorption experiments. The effects of various parameters like dosage effect, effect of pH, initial concentration of the dye and contact time on the adsorption capacity of MB dye on WCFAC are reported. It was found that, maximum adsorption (~88%) was observed at pH 6 with a good sorption capacity (~21 mg/g) of dye. The adsorption isotherms are analyzed by Langmuir and Freundlich models. The sorption data were better fitted by the Freundlich isotherm model as evident from the R 2 value 0.940. Adsorption kinetics was performed and obeys pseudo-second-order kinetic model (R 2 at 0.9325). The zero point charge for the WCFAC was found to be 4.9 pH. pH optimization studies show that the favorable adsorption range ~4-6 pH. Experimental and kinetic results reveal that WCFAC is a potential adsorbent for the adsorption of MB dye from aqueous solution.

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a b s t r a c tThe present study is aimed at efficient removal of Cr(VI) ions from aqueous solution by employing CaAl 2 O 4 nanoparticles. CaAl 2 O 4 nanoparticles were synthesized by solution combustion method by employing two different fuels: glycine and oxalyl dihydrazide. Powder X-ray diffraction, Fourier transmission infrared spectroscopy, scanning electron microscope, and energy dispersive analysis of X-rays were used to characterize the CaAl 2 O 4 adsorbent before and after adsorption process. CaAl 2 O 4 nanoparticles synthesized by glycine as fuel (CAG) exhibited excellent Cr(VI) ions removal compared with CaAl 2 O 4 nanoparticles obtained by oxalyl dihydrazide as fuel (CAO) from aqueous solution at pH 7. The greater adsorption capacity of CAG compared with CAO can be attributed for the fact that CAG has smaller crystallite size about ~8 nm compared with CAO which has crystallite size about 19 nm. Both CAG and CAO obey second-order kinetics for Cr(VI) ion removal. Correlation coefficient (R 2 = 0.9328 and 0.9213) and adsorption capacity (48.58 and 11.44 mg/g) were obtained for Freundlich and Langmuir isotherm models, respectively, for CAG and CAO.

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