Preparation and photocatalytic kinetics of nano-ZnO powders by precipitation stripping process

Ultra-fine zinc oxalate powders were prepared through a precipitation stripping method with bis(2-ethylhexyl)phosphate(HDEHP)diluted by tetrachloride carbon as the extractant,and oxalic acid ethanol aqueous solution as the re-extractant and precipitator.Zinc oxide powders were obtained by decomposing zinc oxalate powders at 450℃.The prepared zinc oxide powders were characterized by transmission electron microscope(TEM),Scanning electron microscope(SEM),Thermogravimetric analysis(TG),X-ray diffraction(XRD)and Fourier transmission infrared(FT-IR)spectrum.The photocatalytic performance of methylene blue by zinc oxide was studied based on the Langmuir model and Photo-Layer model.The results show that some zinc oxide powders were micro-multipore materials with hexagonal crystal.The particle size was around 32 nm.The photocatalytic process was the control step in the chemical reaction.The photo catalytic process followed pseudo-first order kinetics and NOH concentration inside the photo-layer in different reaction condition were calculated according to the Photo-Layer model.