Preparation Of Iron-pillared Montmorillonite And Catalytic Wet Peroxide Oxidation Of Phenol

Phenol and relevant derivatives are extremely important raw materials in chemical industry and pharmaceutical industry. In recent years, with the continuous development of the two industries, phenolic wastewater treatment has become the focus of the society. Because of stable molecular structure, high toxicity and low biodegradability, the traditional technology is difficult to achieve efficiency degradation. This work attempted to remove phenol in the use of heterogeneous catalytic wet peroxide oxidation ?CWPO? technology. The series of Fe,Ce,Al-MMT pillared catalyst were synthesized by polycation exchange methodology, focusing on optimizing the structural and catalytic properties of the catalysts and aiming to solve low degradation and easy leaching problem.The relationship between different preparing conditions ?Fe/Ce molar ratio in the pillaring solution, active metal loading and calcinated temperature? and the properties of Fe,Ce,Al-MMT catalyst was examined, the catalytic behaviour of Fe,Ce,Al-MMT was studied through the CWPO degradation of phenol ?COD removal and Fe leaching were used as evaluation index?. Meanwhile, Characterization technologies were performed by ICP?XRD? N₂ adsorption-desorption?FTIR?DR UV-Vis?SEM and H₂-TPR in order to analyze the micro morphology and active components of pillared catalyst. The results show that pillared treatment can effectively improve the physicochemical property of montmorillonite.The Fe,Ce,Al-MMT with Fe/Ce molar ratio of 7/3, active metal loading of 6% and calcinated temperature of 450? performed better, which obtained increased layer distance?d001 2.649nm?, larger specific surface ?181.2m2/g?, more dispersive active phases and stronger stability. When 450?-6%Fe,Ce,Al-MMT was chosen to catalyze phenol, the COD removal can reach to 94.48%, accompanied by only 0.6528mg/L Fe leaching after 5h of reaction.The selected 450?-6%Fe,Ce,Al-MMT was used as catalyst in CWPO reaction of phenol. The effect of reaction conditions ?reaction temperature, catalyst dosage and intial pH? on the degradation of phenol was investigated. According to the kinetic parameters and oxidation indexes such as COD removal andFe leaching, the optimized reaction condition was affirmed. After 5h, the COD removal of phenol can reached 94.48% and the Fe leaching was only 0.6528mg/L at temperature of 60?, catalyst dosage of 1.0 g/L and intial pH of 5.0. Besides, the single used 450?-6%Fe,Ce,Al-MMT catalyst was analyzed by further characterization studies, like BET?SEM?DR UV-Vis. It found that the acidic reaction medium can't bring a significant influence on the structure and the active phases. After successive fifth catalytic experiment, the COD removal of phenol decreased only 6%, which demonstrated the catalyst solid possessed superior stability.The CWPO mechanism was also studied in detail. It showed that free hydroxyl radicals HO·from the decomposition of H₂O₂ was the predominant oxide in the heterogeneous CWPO system and whose formation rate strongly influenced by the variation of pH value during the reaction. The first order kinetic model could fit the experimental data well. The apparent activation energy Ea of COD removal in this system was 17.64KJ/mol.In the last part, the prepared methodology was improved in order to decrease the amount of water. Distilled water was replaced by ethanol solution and the different dispersion medium on physicochemical properties and catalytic performance of sample was investigated. The results indicated that the properties of catalyst synthesized by ethanol was comparable to those of catalyst synthesized by conventional water, which can proved the feasibility of this methodology.