Photocatalytic degradation of reactive brilliant blue X-BR with Al-doped ZnO nano-particles

Pure ZnO and Al-doped ZnO particles were prepared using sol-gel method with zinc acetate dehydrate [Zn(CH₃COO)₂·2H₂O], lithium hydroxide monohydrate (LiOHH₂O) and aluminum chloride (A1Cl₂·6H₂O) as raw material. The samples were characterized by means of X-ray diffraction, infrared absorption spectroscopy, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and high resolution transmission electron microscope. The photocatalytic performance of different ZnO samples was studied using ultraviolet lamp as illumination device and reactive brilliant blue X-BR as stimulant pollutant. The effects of calcining temperature of precursor, photocatalytic temperature, irradiation time, concentration of pollutant, dark adsorption performance of the samples, amount of Al doping and content of catalyst on the degradation rate of reactive brilliant blue X-BR were investigated. The results indicated that when the calcining temperature was 300°C, the ZnO crystals crystallized well and the size of ZnO particles was small. Al doping to ZnO improved the photocatalytic performance of ZnO samples and the uniformity of the particles, but it did not improve the adsorption performance. Moreover, the Al-doped particles became much smaller evidently. In the doped samples (Al doping range 1%-7%), 5%Al-ZnO was the most active. When the reaction temperature was 30°C, the degradation rate of reactive brilliant blue X-BR could reach 95% by catalyst of 0.1 g/L in 45 min.