Study On Preparation And Photocatalysis Of Polyimide/ Zinc Oxidebase Composite Films

This research used the polyimide?PI?as the carrier,and adopted ion exchange process to prepare polyimide/Zinc Oxide bace composite films.Firstly,ZnO/PI composite films were prepared by the surface modification and ion exchange process.The photocatalysts were characterized by X-ray powder diffraction?XRD?,scanning electron microscopy?SEM?,energy dispersive analysis of X-rays?EDX?,ultraviolet-visible diffuse reflectance spectroscopy?UV-vis DRS?and and Thermal Gravity Analysis?TGA?.Photocatalytic degradation tests show an efficient degradation ability of ZnO/PI composite membranes through the photocatalytic degradation of methyl orange.The preparation conditions?alkaline?alkaline Hydrolysis time?zinc concentratio?heating temperatures ? hoding time?influencing photocatalysis are discussed.Furthermore,the composite films were modified by compounding metaloxide?Fe,Ni and Ce?,and the effects of additive amount of metal ions in the ion exchange liquid on the photocatalytic properties of the composite films were studied.?1?The product displayed a hexagonal wurtzite structure,and no agglomerates can be observed.Composite films retain the original structure and properties of polyimide but the optical transmittance of ZnO/PI is increasing.The preparation conditions influencing photocatalysis are discussed.The result showed that the composite polyimide had higher actibity which was dipped in 2 mol·L^-1potassium hydroxide solution for 90 min firstly,and then adopted ion exchange for 3 h in solution of 0.05 mol·L^-1 zinc concentration,last,heat treated at 410?for 5 h had the best photocatalytic activity,and the degradation rate of methyl orange after 4h was 99.5%.?2?ZnO/PI films were modified by compounding iron oxides,and improved the loading amount of iron and photocatalytic actibity of composite films by changing the ion exchange liquid.The results showed that the composite films had the best photocatalytic activity when the additive amount of Fe3+ in ion exchange liquid was 10%.And the films were dipped in 2 mol·L^-1potassium hydroxide solution for 90 min firstly,and then adopted ion exchange for 3 h,last,heat treated at 430? for 5 h had the best photocatalytic activity,and the degradation rate of methyl orange after 3.7 h was 98.0%.?3?ZnO/PI films were modified by compounding iron oxides and cerium oxides,when the additive amount of Ce4+in ion exchange liquid was 6% which dipped in 2 mol·L^-1potassium hydroxide solution for 90 min firstly,and then adopted ion exchange for 3 h in meral solution,last,heat treated at 450? for 4 h had the best photocatalytic activity,and the degradation rate of methyl orange after 3.4 h was98.3%.?4?ZnO/PI films were modified by compounding iron oxides and nickel oxides,when the additive amount of Ni2+ in ion exchange liquid was 1% were dipped in 2 mol·L^-1potassium hydroxide solution for 90 min firstly,and then adopted ion exchange for 3 h in metal solutions,last,heat treated at 440? for 4 h had the best photocatalytic activity,and the degradation rate of methyl orange after 3.5 h was 98.8%.