Study On The Synthesis Of Perovskite Oxides By Micro-wave And The Photocatalytic Degradation Of Acid Red

Perovskite type ABO₃ oxides is inorganic non-metal material which has many function of physics and chemical, there are many research reports about its electricity, magnetism, but a little about its photocatalytic. Perovaskite type ABO₃ oxides were synthesized by method of microwave sol-gel process, A includes alkaline-earth metals such as Ca, Sr, while B includes transition metal Fe, Ni. Photocatalytic degradation experiments of water-soluble acidity red of waste water in systems of perovskite type ABO₃ oxides were carried out in this paper, and the effect of condition of photocatalytic degradation on degradation rate. The methods of XRD and infrared spectrum technology are used to analyze perovskite type ABO₃ oxides.On the basis of these factors, the synthetic condition was optimized as follows: while nitrate of A, B is 0.1mol·L^-1, 0.1mol·L^-1 citric acid=75mL; microwave heating power is 700W; microwave heating time is 30 minutes; calcining time is 5h. The results of orthogonal experiment verify the accuracy of single factor experiment, and conclude the influential sequence of influential preparation factors for pillared bentonites. X-ray diffraction tells us that all of these catalzers are perovskite type. Tolerance factor(t) of CaNiO3, SrNiO₃, CaFeO₃, SrFeO₃ are 0.88, 0.93, 0.89, 0.94, all in the extension. Infrated spectrum show the exist of oxy-carbonate.Secondly we systematically study the influential factors, by four catalyzers degradation of acidity red of waste water. The optimal conditions of acidity red degradation are as following: acidity circumstance are better for degradation, 30 mg·L^-1 for initial concentration of solution of acidity red, if initial concentration is too high, molecule dye will be adsorbed on catalyzers, catalyzers absorbing light will be tamped; 0.2g catalyzer, dyestuff will not be degraded completely if catalyzers are less, more will influence catalyzers absorbing light; 2h for reaction time. In condition of catalysts and no light, the solution in a short time degradation rate increases, then there is no significant changes. This is the dominant role of physical adsorption. Finally the kinetics of degradation of acidity red is studied over SrNiO3 catalyst. the reaction order is defined to be 1.3, the avtivation energy is Ea=33.53kJ·mol^-1, and pre-exponential factor in k0=4.38×10⁵mol^-0.3·L^0.3·min^-1.