Preparation Of Nano-sized Membrane Metal-Oxide Particles By UF Method And Their Catalysis Performance

Nanostructure metal-oxide was one kind of important catalyst.Using membrane technology to prepare nano-particles was one of the hopspots of the study in field of nanotechnology in recent years. Which used microfiltration membrane or ultfiltration as dispersion medium, under the effect of pressure, the solution was forced to get through the membrane into another phase. Comparing with traditional method, it had obviously more advantage.Firstly, catalysts of CuO was prepared by chemical precipitation (CP) method, submerged hollow fiber UF membrane method and tube-and-shell hollow fiber UF membrane (TSUF) method. The effects of preparating methods and synthetic conditions, including preparating temperature, molar ratio of reactants, membrane filtration velocities and different precipitants, on the structure and catalytic performance of CuO for cumene oxidation were also discussed. UF membrane method prepared CuO has the best structure and catalytic performance. Meanwhile, the best preparating conditions for CuO by TSUF method were also decided.Secondly, CuO based compositing and blending nano-sized metal catalysts, ZnO-CuO and ZnO/CuO, were prepared and the catalytic performance for cumene oxidation were also investigated. The structure and catalytic performance of ZnO-CuO was superior to that of ZnO/CuO. The addition of ZnO amended the catalytic selectivity of ZnO-CuO with 25 wt% ZnO the best dosage.Finally, complex catalyst ZnO-CuO prepared by TSUF method was used for cumene oxidation. Meanwhile, catalytic conditions such as oxidation temperature, ZnO-CuO dosage and air flux on the catalytic performance was also studied. The results showed that cumene hydroperoxide (CHP) productivity and selectivity reached 38.74% and 84%, respectively when the oxidation temperature is 90℃, ZnO-CuO dosage is 8-9g/L and air flux is 700mL/min.Studies showed that TSUF method CuO compared with CP method CuO,CHP yield enhances more than 40%; selectivity of TSUF method 25%ZnO-75%CuO increased over 12% than that of TSUF method CuO with CHP yield a few increased. In addition, the TSUF method 25%ZnO-75%CuO can be recycled.