ZnO doped SnO 2 has been successfully synthesized by the solvothermal method using methanol as or... more ZnO doped SnO 2 has been successfully synthesized by the solvothermal method using methanol as organic solvent. The effect of ZnO/SnO 2 molar ratios on the crystal structure, microstructure, optical and photocatalytic properties has been investigated. The synthesized samples are characterized by X-ray diffraction, transmission electron microscopy, N 2 physical adsorption, FT-IR spectroscopy and UV-Vis spectroscopy. XRD results revealed that all diffraction peaks positions agree well with the reflection of a tetragonal rutile structure of SnO 2 phase without extra peaks at 0.1ZnO:0.9SnO 2 and 0.2ZnO:0.8SnO 2 molar ratios. However, the secondary phase of ZnO at 0.3ZnO:0.7SnO 2 molar ratio was investigated. TEM images revealed that the shape of SnO 2 particles was spherical and the particle sizes of SnO 2 and 0.3ZnO:0.7SnO 2 molar ratio were 6.2 and 16.4 nm, respectively. The newly prepared samples have been tested by the determination of photocatalytic degradation of methylene blue (MB). The results indicated that Zn 2+ doping at 0.3ZnO:0.7 SnO 2 molar ratio showed the highest photocatalytic activity for the MB photodegradation. The heightened photocatalytic activity of ZnO/SnO 2 could be ascribed to the enhanced charge separation derived from the coupling of ZnO with SnO 2 due to the potential energy differences between SnO 2 and ZnO. The recycling tests demonstrated that 0.3ZnO:0.7 SnO 2 photocatalysts were quite stable during that liquid-solid heterogeneous photocatalysis since no decrease in activity in the first four cycles was observed.
Bacterial leaching of copper, nickel and cobalt from a complex sulphide ore was studied in shake ... more Bacterial leaching of copper, nickel and cobalt from a complex sulphide ore was studied in shake flask experiments using Thiobacillus ferrooxidans at 20 °C. After 20 days of leaching all 90% of Cu, 70% Co and 95% Ni was extracted from the ore. For all sulphide minerals present in the studied ore samples, the data emphasizes that the fastest leaching rates are achieved under oxidizing conditions and low pH (< 2.5) values, where a considerable portion of ferric iron remains in the solution.
Synthesis of ZnO nanoparticles was carried out by hydrothermal technique in the presence of hexam... more Synthesis of ZnO nanoparticles was carried out by hydrothermal technique in the presence of hexamethylenetetramine (HMTA) as a surfactant. Statistical design was used to investigate the effect of main parameters (i.e., surfactant concentration, time and temperature) on ZnO particle size and morphology. The results indicated that the formation of ZnO nanoparticles was confirmed, using XRD and SEM, at 100 °C
Egyptian bentonitie clays from Qasr EI-Sagha, Wadi EI-Rayan, Kom Oshim and the Cairo-Alexandria d... more Egyptian bentonitie clays from Qasr EI-Sagha, Wadi EI-Rayan, Kom Oshim and the Cairo-Alexandria desert road were studied thermally (TG, DTG and DTA) and structurally (XRD and IR). The clay fraction consisted mainly of montmorillonite, kaolinite and some illite. Gypsum, quartz and calcite were also identified. It was found that the Na-to Ca-montmorillonite ratio increases in the following sequence: Qasr EI-Sagha<Wadi El-Rayan<Kom Oshim<Cairo-Alexandria desert road. There is a marked concentration of gypsum, the highest amount occurring in the bentonite from Qasr EI-Sagha, and the least in that from the Cairo-Alexandria desert road. Calcite was mainly found in Kom Oshim, with a very small amount from the Cairo-Alexandria desert road. Magnesium is more abundant than iron in the oetahedral layer and increases in the following sequence: Cairo-Alexandria desert road<Kom Oshim<Wadi E1-Rayan<Qasr EI-Sagha.
Journal of Superconductivity and Novel Magnetism, 2012
An investigation of the synthesis of BaFe 12 O 19 powders by the organic acid precursor method is... more An investigation of the synthesis of BaFe 12 O 19 powders by the organic acid precursor method is reported by acidic and neutral media. X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) are utilized to study the effect of organic precursor type and annealing temperature on the crystal structure, crystallite size, microstructure and magnetic properties of the formed powders. The XRD analysis showed that the crystalline BaFe 12 O 19 phase was obtained at 1200°C for 2 h using different carboxylic acids in acidic medium. However, pure BaFe 12 O 19 was achieved at low annealing temperature 1000°C in neutral medium. SEM micrographs showed that the particles were strongly influenced by type of carboxylic acid and the annealing temperature. VSM study indicated that the saturation magnetization was increased with increasing annealing temperature to 1200°C as the result of formation of single barium hexaferrites phase. High saturation magnetization (M s = 66.5 emu/g) was achieved for the formed powders in neutral medium using tartaric acid as organic precursor. Wide coercivities of the formed powders (H c = 259-5114 Oe) were obtained.
Low grade manganese ore from West-Central Sinai consists mainly of pyrolusite and hematite with m... more Low grade manganese ore from West-Central Sinai consists mainly of pyrolusite and hematite with minor amounts of psilomelane and barite. Manganese dioxide does not dissolve in sulfuric acid under atmospheric pressure, but rapidly dissolves under oxygen pressure in an autoclave in presence of pyrite. Pyrite is oxidized to ferrous sulfate and sufluric acid which in turn dissolves manganese dioxide to manganese sulfate. This pressure leaching process was systematically studied. Almost complete extraction of manganese was achieved at temperature 220 °C under oxygen pressure of 15 bar after 30 minutes of leaching and at MnO 2 /FeS 2 molecular weight ratio equal 1.0. The residue is encriched in iron so that it could be used to produce feed stock for iron smelting.
Cyanides used in some chemical synthesis and metallurgical processes are highly toxic and must be... more Cyanides used in some chemical synthesis and metallurgical processes are highly toxic and must be destroyed or removed from wastewaters prior to discharge. Vanadia–silica xerogel as photocatalyst has been prepared via sol–gel technique by dissolving ammonium ...
ZnO doped SnO 2 has been successfully synthesized by the solvothermal method using methanol as or... more ZnO doped SnO 2 has been successfully synthesized by the solvothermal method using methanol as organic solvent. The effect of ZnO/SnO 2 molar ratios on the crystal structure, microstructure, optical and photocatalytic properties has been investigated. The synthesized samples are characterized by X-ray diffraction, transmission electron microscopy, N 2 physical adsorption, FT-IR spectroscopy and UV-Vis spectroscopy. XRD results revealed that all diffraction peaks positions agree well with the reflection of a tetragonal rutile structure of SnO 2 phase without extra peaks at 0.1ZnO:0.9SnO 2 and 0.2ZnO:0.8SnO 2 molar ratios. However, the secondary phase of ZnO at 0.3ZnO:0.7SnO 2 molar ratio was investigated. TEM images revealed that the shape of SnO 2 particles was spherical and the particle sizes of SnO 2 and 0.3ZnO:0.7SnO 2 molar ratio were 6.2 and 16.4 nm, respectively. The newly prepared samples have been tested by the determination of photocatalytic degradation of methylene blue (MB). The results indicated that Zn 2+ doping at 0.3ZnO:0.7 SnO 2 molar ratio showed the highest photocatalytic activity for the MB photodegradation. The heightened photocatalytic activity of ZnO/SnO 2 could be ascribed to the enhanced charge separation derived from the coupling of ZnO with SnO 2 due to the potential energy differences between SnO 2 and ZnO. The recycling tests demonstrated that 0.3ZnO:0.7 SnO 2 photocatalysts were quite stable during that liquid-solid heterogeneous photocatalysis since no decrease in activity in the first four cycles was observed.
Bacterial leaching of copper, nickel and cobalt from a complex sulphide ore was studied in shake ... more Bacterial leaching of copper, nickel and cobalt from a complex sulphide ore was studied in shake flask experiments using Thiobacillus ferrooxidans at 20 °C. After 20 days of leaching all 90% of Cu, 70% Co and 95% Ni was extracted from the ore. For all sulphide minerals present in the studied ore samples, the data emphasizes that the fastest leaching rates are achieved under oxidizing conditions and low pH (< 2.5) values, where a considerable portion of ferric iron remains in the solution.
Synthesis of ZnO nanoparticles was carried out by hydrothermal technique in the presence of hexam... more Synthesis of ZnO nanoparticles was carried out by hydrothermal technique in the presence of hexamethylenetetramine (HMTA) as a surfactant. Statistical design was used to investigate the effect of main parameters (i.e., surfactant concentration, time and temperature) on ZnO particle size and morphology. The results indicated that the formation of ZnO nanoparticles was confirmed, using XRD and SEM, at 100 °C
Egyptian bentonitie clays from Qasr EI-Sagha, Wadi EI-Rayan, Kom Oshim and the Cairo-Alexandria d... more Egyptian bentonitie clays from Qasr EI-Sagha, Wadi EI-Rayan, Kom Oshim and the Cairo-Alexandria desert road were studied thermally (TG, DTG and DTA) and structurally (XRD and IR). The clay fraction consisted mainly of montmorillonite, kaolinite and some illite. Gypsum, quartz and calcite were also identified. It was found that the Na-to Ca-montmorillonite ratio increases in the following sequence: Qasr EI-Sagha<Wadi El-Rayan<Kom Oshim<Cairo-Alexandria desert road. There is a marked concentration of gypsum, the highest amount occurring in the bentonite from Qasr EI-Sagha, and the least in that from the Cairo-Alexandria desert road. Calcite was mainly found in Kom Oshim, with a very small amount from the Cairo-Alexandria desert road. Magnesium is more abundant than iron in the oetahedral layer and increases in the following sequence: Cairo-Alexandria desert road<Kom Oshim<Wadi E1-Rayan<Qasr EI-Sagha.
Journal of Superconductivity and Novel Magnetism, 2012
An investigation of the synthesis of BaFe 12 O 19 powders by the organic acid precursor method is... more An investigation of the synthesis of BaFe 12 O 19 powders by the organic acid precursor method is reported by acidic and neutral media. X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) are utilized to study the effect of organic precursor type and annealing temperature on the crystal structure, crystallite size, microstructure and magnetic properties of the formed powders. The XRD analysis showed that the crystalline BaFe 12 O 19 phase was obtained at 1200°C for 2 h using different carboxylic acids in acidic medium. However, pure BaFe 12 O 19 was achieved at low annealing temperature 1000°C in neutral medium. SEM micrographs showed that the particles were strongly influenced by type of carboxylic acid and the annealing temperature. VSM study indicated that the saturation magnetization was increased with increasing annealing temperature to 1200°C as the result of formation of single barium hexaferrites phase. High saturation magnetization (M s = 66.5 emu/g) was achieved for the formed powders in neutral medium using tartaric acid as organic precursor. Wide coercivities of the formed powders (H c = 259-5114 Oe) were obtained.
Low grade manganese ore from West-Central Sinai consists mainly of pyrolusite and hematite with m... more Low grade manganese ore from West-Central Sinai consists mainly of pyrolusite and hematite with minor amounts of psilomelane and barite. Manganese dioxide does not dissolve in sulfuric acid under atmospheric pressure, but rapidly dissolves under oxygen pressure in an autoclave in presence of pyrite. Pyrite is oxidized to ferrous sulfate and sufluric acid which in turn dissolves manganese dioxide to manganese sulfate. This pressure leaching process was systematically studied. Almost complete extraction of manganese was achieved at temperature 220 °C under oxygen pressure of 15 bar after 30 minutes of leaching and at MnO 2 /FeS 2 molecular weight ratio equal 1.0. The residue is encriched in iron so that it could be used to produce feed stock for iron smelting.
Cyanides used in some chemical synthesis and metallurgical processes are highly toxic and must be... more Cyanides used in some chemical synthesis and metallurgical processes are highly toxic and must be destroyed or removed from wastewaters prior to discharge. Vanadia–silica xerogel as photocatalyst has been prepared via sol–gel technique by dissolving ammonium ...
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