Study On The Synthesis Of La_0.8k(₀.2)feo₃ Perovskite Composites And The Photocatalytic Degradation Of Dye Wastewater

Perovskite-type composite materials (ABO₃) is a stable crystal structure functional materials which has specific physical and chemical properties natures. After extensive research found that it not only has a strong photocatalytic oxidation, but also can be prepared by a narrower band gap photocatalyst by changing the A,B atoms, so that it can respond in the visible light. In addition, multi-component perovskite-type composite material can be synthesized through the A bit and B bit partial replacement, it has great significance in the field of heterogeneous catalysis. In this paper,we use A,B-bit element of nitrate as raw materials and citric acid as dispersant to prepared a series of perovskite-type composite material with Sol-gel method. A Choice of rare earth elements of La, B bits select the transition metal elements Fe, and studied out by changing the preparation conditions of better LaFeO₃ preparation conditions. And then alkaline-earth metal K pairs of A-bit to 20% of the proportion of the doping, using La_0.8K_0.2FeO₃ as active monomer, selected transition metals Cu on the B bits as doping elements, investigated the composite materials , photocatalytic oxidation which prepared under the condition of the better doped in the actual dye wastewater.Using 300W high pressure mercury lamp as light source, carried out on the water-soluble dyes photocatalytic oxidation degradation test, and study the photocatalytic oxidation by the decolorization rate of series samples. Re-use of XRD, SEM, photoacoustic spectroscopy, EDS analysis were characterized by means of focusing on the higher rate of dye decolorization morphology and properties of the sample. Studies have shown that:(1) Photocatalyst during the preparation of the various parameters such as pH, temperature, etc. into a plastic can affect the activity of photocatalysts. (2) Small amount of doping can significantly improve the catalytic activity, the reason is that the increase of positive charge imbalance in the number of oxygen vacancies, so that the catalytic activity increased, but when the doping gradually increases, activity of the catalyst is fall, so there is an optimal doping ratio.Industrial dye wastewater was treated by photocatalytic oxidation degradation test, various factors impacted degradation effect were be researched: the degradation rate of dye wastewater increases with the amount of catalyst increased gradually, but decreases when the amount of catalyst increased to a certain amount t; catalysts has higher catalytic activity under acidic conditions, with the pH value increases, the dye wastewater degradation rate gradually decreases; decolorization of dye wastewater was significantly increased After adding H₂O₂ degradation .The results show that the synthesis of La_0.8K_0.2Fe_0.96Cu_0.04O₃ has a strong photocatalytic oxidation, Low-concentration organic waste water can be decomposed into direct oxidation of H2O, CO₂ and other inorganic small molecules, for the high concentration of dye wastewater mineralization rate was lower, but the complexity of composite materials in which pollutants can be degraded to shorter carbon chain of organic matter, greatly enhanced the biodegradability of wastewater, laying a good foundation for follow-up biochemical treatment of wastewater.