The objective of this research was to prepare multi–phase bismuth vanadate (BiVO4) powder using the solvothermal method to be used as a photocatalyst. In the preparation step, bismuth nitrate and ammonium vanadate were used as the precursors with a mole ratio of 1:1. The mixed solution was diluted to 0.025 M with acetic acid and heated at 200 °C for 2 h in a Teflon–lined stainless steel autoclave vessel. Multi–phase BiVO4was obtained without calcination step. Multi–phase BiVO4was characterized by X–ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT–IR), and energy dispersive spectroscopy (EDS). The efficiency of multi–phase BiVO4for photocatalytic degradation of the mixed dye of methylene blue (MB) and rhodamine B (RhB) solution under UV light irradiation was studied. The concentration of the mixed dye solution was measured by UV–Vis spectrophotometry (UV–Vis). The effect of concentration of catalyst and pH of solution was studied. The optimum conditions for photocatalytic degradation of mixed dye solution were obtained at 0.8 g/L for concentration of multi–phase BiVO4and 7.78 for initial pH of the mixed dye solution.

Natural diatomite was modified by manganese chloride via the low temperature hydrothermal route. The chemical properties and adsorption efficiency of the natural and the modified diatomite were characterized. The chemical compositions of the natural and the modified diatomite were determined by X-ray fluorescence spectroscopy (XRF) and energy dispersive X-ray spectrometry (EDXS). Morphology of the natural and the modified diatomite was investigated by scanning electron microscopy (SEM). The adsorptions of Cd (II) and Pb (II) ions onto the natural and the modified diatomite were determined by atomic absorption spectroscopy (AAS).

In this paper, α–Fe2O3 photocatalyst with enhanced solar–driven photocatalytic activity was obtained from natural local groundwater sediment using a chemical solution method with subsequent calcination. The phase structures and crystallite size characterized by X–ray diffraction. The morphology and the particle size were investigated by scanning electron microscopy. The α–Fe2O3 was used as a catalyst to photodegrade MB under visible light illumination. The photocatalytic reaction rate constant of the α–Fe2O3 photocatalyst in the photocatalytic degradation of MB dye solution under LED light illumination with the presence of H2O2 was calculated to be 1.70×10–2 min–1. Moreover, the effect of H2O2 concentration on photocatalytic efficiency and the photocatalytic mechanism also were discussed.

Bismuth vanadate (BiVO4) powder was synthesized via the solvothermal method at 100200 °C for 26h by using acetic acid as solvent without calcination steps. The phase transition of BiVO4 powder was studied by Xray diffraction (XRD). The morphology and chemical composition of BiVO4 powder were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The functional groups of BiVO4 powder was identified by Fourier transform infrared spectroscopy (FTIR).

Titanium dioxide (TiO2) powder was synthesized via the solvothermal method. Titanium isopropoxide (C12H28O4Ti), ammonium hydroxide (NH4OH) and nitric acid (HNO3) were used as the starting materials. The mixed solution was diluted with ethanol (C2H5OH) and heated at 100°C for 5h in a Teflon–lined stainless steel autoclave vessel. The phase transition of TiO2 powder was studied by X–ray diffraction (XRD). The morphology and chemical composition of TiO2 powder were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The photocatalytic degradation of methylene blue and methyl orange over TiO2 powder were determined using Ultraviolet–visible spectroscopy (UV–Vis).