Preparation Of ZnO Nanomaterials And Study On Photoelectrocatalytic Degradation Of Phenol Solution

Phenol is a kind of organic pollutant which do harm to people seriously. It exists commonly in the waste water from coking factories, paper mills, resinic mills, printworks, perochemical plants, et al. In this paper, we choose phenol as a typical organic pollutant of water, taking the prepared ZnO nanomaterials as the photocatalysts to degradate the phenol solution by the photoelectrocatalytic technology.Nanometer ZnO powders were prepared by sol-gel method.The structure and performance of the sample were studied by XRD,TEM and UV-Vis.The results show that the ZnO powders prepared at different roasting temperatures are the hexagonal wurtzite structure, the grain size of the sample from 19 to 30 nanometers.The nano-ZnO powders have the strong absorption peak in the ultraviolet ray area(200nm-400nm) and the absorption limits are about 245nm and 380nm. The photocatalysis performance of nanometer ZnO powders prepared at the roasting temperature 650℃are preferable.The nano-ZnO films were prepared on glass substrates by natural extension method.With two 40W fluorescent lamps and 300W high pressure mercury lamp as light source,the photocatalytic performance of nano-ZnO flim was studied by the degradation experiment of phenol.The results indicate that the photocatalytic activity of ZnO film are stonger than the nano-ZnO powders under the scope and experimental conditions of our researches, the optimum condition of degradation experiment of phenol at the irradiation of fluorescent lamp is as follows: ZnO dosage 0.070g, the irradiation time 90min and the initial concentration of phenol 150mg/L,and the optimum condition at the irradiation of high pressure mercury lampis as follows: ZnO dosage 0.050g,the initial concentration of phenol 150mg/L and the irradiation time 45min.The photocatalytic activity of prepared ZnO film disappear after using four times.The photoelectrocatalytic performance of nano-ZnO electrodes prepared by coating technique were studied by the degradation experiment of phenol.The results indicate that the photoelectrocatalytic reaction has the higher degeneration efficiency comparing with the electrocatalytic reaction. The optimum condition of photoelectrocatalytic degradation experiment of phenol at 20℃is as follows: external potential 2.0V, Na2SO4 concentration 0.070mol/L and distance between the electrode 0.60cm. The kinetic study shows that degradation reaction of phenol is the first grade reaction.The HPLC analysis results indicate that the products of photocatalytic degradation of phenol solution include hydroquinone, catechol, benzoquinone, maleic acid,fumaric acid and so on.