Structure Regulation Of ZnFe₂O₄ And The Envioronmental Application

In this subject, ZnFe2O4 was prepared by co-precipitation and sol-gel methods, and they were applied to Microwave Induced Catalytic Oxidation (MICO) process. Results found microwave irradiation enhanced the releasing of alkali remained in materials and then discolored three toluene acidic dyes. Then, microwave was introduced into calcination process, perfect structure and properties of the composites were obtained by this special heating method.In order to regulate ZnFe2O4 structures, the preparation process was divided into two processes, including precursor preparation and calcination. During the studying of preparation process, co-precipitation method and sol-gel method were used to prepare ZnFe2O4 precursors. Then the ZnFe2O4 precursors were both calcined by muffle furnace (air atmosphere). Comparative studying on the structural differences and found that, ZnFe2O4 materials prepared by co-precipitation method remained alkali, which would impact environmental applications. While, in the calcination process, microwave calcination (nitrogen atmosphere), muffle furnace calcinations (air atmosphere) and tube furnace calcination (nitrogen atmosphere) were applied to calcined ZnFe2O4 precursors prepared by sol-gel method. Comparative studying found that ZnFe2O4 calcined by microwave calcinations obtained properties of larger specific surface area, carbon doped, porous surface, low crystallinity and small band gap. Therefore, through our structural regulation process, we successfully prepared ZnFe2O4 material with unique structure.Through the microwave induced catalytic oxidation process, we found that malachite green dyes were decolorized by alkali released from co-precipitation prepared ZnFe2O4 materials. During microwave radiation, the releasing of residual alkaline was enhanced, and then directly decolorized malachite green. The results were proved by the results of degradation of malachite green based on NaOH. In addition, the experimental results showed that it was difficult for the absorbing materials to absorb microwave energy in aqueous system. ZnFe2O4 materials prepared by microwave calcination process were preformed well in environmental application. Results showed that ZnFe2O4 could adsorb 91% Rhodamine B in 16 minutes through adsorption process, and degrade 86% Rhodamine B in 180 minutes through photocatalytic process, which indicated it had broad prospects in environmental application.