Sh. Akbarnezhad ¹, S. M. Mousavi ¹, R. Sarhaddi ²

Affiliations
1 Dept. of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, IR
2 Dept. of Physics, Faculty of Science, University of Birjand, Birjand, IR

Abstract

Alumina-titania ceramic membrane with mesopore and narrow pore size distribution was prepared by the sol-gel process. Observations were based on membrane weight loss, morphology, pore size distribution and BET surface area. Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM) and N₂ adsorption-desorption analysis were employed for the membrane characterization. TGA curve shows that the suitable temperature for calcination of alumina-titania membrane is at 600°C. The SEM morphology displays a smooth and free-crack layer of alumina-titania membrane after calcination at temperature of 600°C. Furthermore, the membrane was also successfully coated with a good adhesion to complement with support. The thickness of the membrane layer was estimated at 4 μm. N₂ adsorption-desorption confirms the existence of a mesoporous structure for membrane as BET surface area and average pore size of the membrane layer were 292 m²g^-1 and 1.8 nm respectively.

Keywords

Alumina-titania, Ceramic Membrane, Sol-gel Process, Dip Coating

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E. Azhir ¹, R. Etefagh ¹, N. Shahtahmasebi ¹, M. Mohammadi ², D. Amiri ³, R. Sarhaddi ⁴

Affiliations
1 Nano Research Center, Faculty of Science, Ferdowsi University of Mashhad, IR
2 Angstrom Thin Film Research Laboratory, Ferdowsi University of Mashhad, IR
3 Fungi lab, Faculty of Science, Ferdowsi University of Mashhad, IR
4 Physics Department, Faculty of Science, University of Birjand, Birjand, IR

Abstract

In this paper, SnO₂ thin film and nanopowder were prepared by spray pyrolysis and sol-gel methods, respectively. The SnO₂ nanostructures were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Then Aspergillus niger fungus were cultured in an appropriate medium and were exposed to the SnO₂ nanofilm and nanopowder. The nano-system electric resistance was measured in the presence of produced gases and the effect of time and temperature on nanobiosensors was studied. Then, SnO₂ nanobiosensor was characterized in the presence of silicagel and calcium carbonate.

Keywords

Aspergillus niger Fungi, Spray Pyrolysis Technique, Sol Gel Method

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A. Rahdar ¹, H. Asnaasahri Eivari ², R. Sarhaddi ²

Affiliations
1 Department of Physics, Faculty of Science, University of Zabol, Zabol, IR
2 Physics Department, Faculty of Science, University of Birjand, Birjand, IR

Abstract

In this paper, we report structural and optical properties of nanocrystalline chromium (Cr) doped ZnS particle, which have been synthesized by co-precipitation method. The structural properties of ZnS:Cr nanoparticles have been characterized by X-ray diffraction (XRD) analysis. The XRD patterns show hexagonal structure in nanoparticles without any additional phase. The mean crystallite size calculated from the XRD patterns has been found in the range 2.45- 1.50 nm with the increase in molar concentration of doping agent. Absorption spectra have been obtained using UV-Vis spectrophotometer to find the optical direct band gap. The obtained values have been founded to being range 3.82- 4.42 eV. It was also found that optical band gap (E_g) increases with the increase in molar concentration of doping agent is attributed to size quantization effect due to the small size of the particles.

Keywords

ZnS:Cr, Chemical Co-precipitation, 2-mercaptoethanol, Optical Band Gap

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