Pusit Pookmanee

Preparation and Characterization of BiVO4 Powder by the Sol-gel Method

Bismuth vanadate (BiVO4) powder was successfully prepared by the sol-gel method. Bismuth nitrate and ammonium vanadate were used as the starting precursors with mole ratio of 1:1 in ethanol media at 70°C for 1 h. The yellow gel was calcined at 400–600°C for 2 h. The phase of BiVO4 powder was characterized by X-ray diffraction (XRD). The morphology and chemical composition of BiVO4 powder were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). The functional groups of BiVO4 powder was identified by Fourier transform infrared spectroscopy (FTIR) and the surface area of BiVO4 powder was determined by Brunauer, Emmett and Teller technique (BET).

LOW TEMPERATURE HYDROTHERMAL SYNTHESIS OF BISMUTH SODIUM TITANATE NANOPOWDERS

Nanopowders bismuth sodium titanate (Bi0.5Na0.5TiO3, BNT) were synthesized by the hydrothermal route at low temperature in the range of 150-200°C with different holding periods of 5-20 h. Bismuth nitrate, sodium nitrate and titanium (IV) isopropoxide were used as the starting materials. The phase structure was examined using X-ray diffraction (XRD). The morphology of the formed nanopowders was investigated by scanning electron microscopy (SEM). Rhombohedral BNT nanopowders was obtained without calcination step. The spherical nanopowders were agglomerated. The average sizes of particle size were about 50-200 nm.

Multi-Layered TiO2 Films towards Enhancement of Escherichia coli Inactivation

Crystalline TiO2 has shown its great photocatalytic properties in bacterial inactivation. This work presents a design fabrication of low-cost, layered TiO2 films assembled reactors and a study of their performance for a better understanding to elucidate the photocatalytic effect on inactivation of E. coli in water. The ability to reduce the number of bacteria in water samples for the layered TiO2 composing reactors has been investigated as a function of time, while varying the parameters of light sources, initial concentration of bacteria, and ratios of TiO2 film area and volume of water. Herein, the layered TiO2 films have been fabricated on the glass plates by thermal spray coating prior to screen printing, allowing a good adhesion of the films. Surface topology and crystallographic phase of TiO2 for the screen-printed active layer have been characterized, resulting in the ratio of anatase:rutile being 80:20. Under exposure to sunlight and a given condition employed in this study, the optimized film area:water volume of 1:2.62 has shown a significant ability to reduce the E. coli cells in water samples. The ratio of surface area of photocatalytic active base to volume of water medium is believed to play a predominant role facilitating the cells inactivation. The kinetic rate of inactivation and its behavior are also described in terms of adsorption of reaction species at different contact times.

Photocatalytic Degradation of Geosmin by Titanium Dioxide Powder Synthesized by the Hydrothermal Route

Titanium dioxide powder was synthesized by the hydrothermal route with the starting precursors as titanium isopropoxide, ammonium hydroxide and nitric acid. The final of pH value of mixed solution was 1 and treated in the hydrothermal PTFE vessel at 80-100 °C for 3h. The phase of titanium dioxide was characterized by X-ray diffractometer (XRD). The morphology of titanium dioxide was investigated by scanning electron microscope (SEM). The chemical composition of titanium dioxide was examined by energy dispersive X-ray spectrophotometer (EDXS). The photocatalytic degradation of geosmin by titanium dioxide was determined by gas chromatograph coupled with flame ionization detector (GC-FID).

Methylene Blue Degradation over Photocatalyst Bismuth Vanadate Powder Synthesized by the Hydrothermal Method

Bismuth vanadate powder was synthesized by the hydrothermal method with bismuth nitrate and ammonium vanadate as the starting precursors with the mole ratio of bismuth and vanadium of 1:1. The mixed solution was adjusted with ammonium hydroxide until the pH of final solution was 7 and hydrothermally treated at 100 °C for 2-6h. The phase was studied by X-ray diffraction (XRD). Monoclinic structure was obtained after hydrothermal treated at 100 °C for 6h without calcination step. The morphology was investigated by scanning electron microscopy (SEM). The particle was needle-like in shape and highly agglomerate. The degradation of methylene blue over photocatalyst bismuth vanadate powder was examined by ultraviolet spectroscopy (UV). Bismuth vanadate powder synthesized by the hydrothermal method at 100 °C for 6h showed the highest photocatalytic activity.

Chemical Synthesis and Characterization of Bismuth Vanadate Powder

Bismuth vanadate powder was synthesized by a chemical co-precipitation method. Bismuth nitrate and ammonium vanadate were used as the starting precursors. The yellow precipitated powder was formed after adding ammonium hydroxide until the pH of final solution was 7. The powder was filtered and dried at 60 °C for 24h and calcined at 200-400 °C for 2h. The phase of bismuth vanadate powder was studied by X-ray diffraction (XRD). A single phase of monoclinic structure was obtained after calcinations at 200-400 °C for 2h. The morphology and particle size of bismuth vanadate powder were investigated by scanning electron microscopy (SEM). The particle was irregular in shape and highly agglomerated with an average particle size of 0.5 µm in width and 1.5 µm in length.

Synthesis and characterization of BiVO4 photocatalyst by microwave method

ABSTRACT Bismuth vanadate (BiVO4) photocatalyst was synthesized by microwave method at 500 Watt for 2, 4 and 6 min. The product was characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The photocatalytic degradation of methylene blue (MB) over BiVO4 photocatalyst was investigated by Ultraviolet-visible spectrometry (UV-Vis). Multi-phase of monoclinic and tetragonal structure of BiVO4 was obtained. The morphology and particle size of BiVO4 showed a spherical-like particle with diameter of 200–400 nm. The photocatalytic activity of BiVO4 photocatalyst prepared at 500 Watt for 4 min showed the highest degradation of MB under UV light irradiation.

Characterization of bismuth vanadate (BiVO4) nanoparticle prepared by solvothermal method

ABSTRACT Bismuth vanadate (BiVO4) nanoparticle was prepared by solvothermal method. The starting precursors were used as bismuth nitrate pentahydrate (Bi(NO3)3•5H2O), ammonium metavanadate (NH4VO3) and absolute ethanol (C2H5OH). Solution I: Bi(NO3)3•5H2O was dissolved in 2.0 M nitric acid (HNO3) and absolute ethanol (C2H5OH). Solution II: NH4VO3 was dissolved in 2.0 M ammonium hydroxide (NH4OH) and absolute ethanol (C2H5OH). The mixed solutions were stirred for 5 min and left into Teflon-lined stainless steel autoclave treatment at 200°C for 3 and 5 h. The yellow final solution was filtered and dried at 100°C for 24 h. All BiVO4 nanoparticle samples were characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectrometer (EDXS) and Fourier transform infrared spectrometer (FTIR).

Microwave-assisted Synthesis Bismuth Vanadate (BiVO4) Powder

Bismuth vanadate (BiVO4) powder was synthesized by the microwave method. Bismuth nitrate pentahydrate (Bi(NO3)3.5H2O) and ammonium vanadate (NH4VO3) were used as the starting precursors with the mole ratio of 1:1. The mixed solution was stirred and adjusted the pH of solution to 7 with ammonium hydroxide (NH4OH). The yellow final solution was treated in the microwave with an irradiation power at 600, 700 and 800 Watt for 2, 4 and 6 min, respectively. The phase of BiVO4 powder was identified by X–ray diffraction (XRD). The morphology and chemical composition of BiVO4 powder were investigated by scanning electron microscopy (SEM) and energy dispersive X–ray spectroscopy (EDXS), respectively. The surface area of BiVO4 powder was determined by Brunauer–Emmett–Teller analysis (BET).

The Photocatalytic Degradation of Phenol and Chlorophenol onto Bismuth Vanadate Powder Prepared by the Solvothermal Method

Bismuth vanadate (BiVO4) powder was prepared by the solvothermal method. Bismuth nitrate and ammonium vanadate were used as the starting precursors with mole ratio of 1:1. The mixed solution was heated in the solvothermal vessel at 100°C for 2–6 h. The phase of BiVO4 powder was characterized by X–ray diffractometer (XRD). The morphology and chemical composition of BiVO4 powder were investigated by scanning electron microscope (SEM) and energy dispersive X–ray spectroscope (EDXS). The surface area of BiVO4 powder was determined by Brunauer, Emmett and Teller analyzer (BET). The photocatalytic degradation of phenol and chlorophenol onto BiVO4 powder was studied and determined by gas chromatograph (GC).