Preparation Of Hollow Spheres Catalysts And Catalytic Wet Oxidation Of Acid Brilliant Scarlet3R

Wet Air Oxidation is an effective method for the treatment of dye wastewater,dyes were degraded to carbon dioxide and water under high temperature and hing airpressure, however, its application was limited by the tough conditions. Catalytic WetOxidation method introduces the catalysts and the reaction activation energy wasreduced because of the catalysts, then Catalytic Wet Oxidation mild the toughconditions. Transition metal oxides have advantages because their abundance andhigh catalytic activities. Hydrogen peroxide acted as oxidant can overcome masstransfer resistance, which milds the reaction condition. We prepared hollow spherecatalyst loaded on hollow silica spheres, and applied in catalytic degradation Acidbrilliant scarlet3R. The research contents in this thesis mainly include:1. Hollow silica spheres were prepared by carbon template which was obtainedfrom glucose solution under hydrothermal condition. Assisted under templating agentCetyl Trimethyl Ammonium Bromide (CTAB), Tetraethyl orthosilicate (TEOS) waschanged into wet gel particles with core-shell structure during hydrolytic process andthe hollow silica spheres were got after drying and calcination. The effect of variousfactors on preparation were studied and the optimal synthesis condition was obtained:the ratio of solvent (ethanol:water) is2:1, the concentration of hydrochloric acid is0.2mol/L. Under such condition the average pore diameter of hollow spheres is4.59nm,BET surface area of hollow spheres is432.29m2/g. The hollow silica sphere particlesare smaller and the BET surface area is larger than the particles prepared byemulsion/sol-gel technology.2. Single component catalysts were prepared by impregnation method. Acidbrilliant scarlet3R solution was chosen as model dye wastewater. CuO/SiO2hollowsphere catalyst was selected to study the CWPO reaction condition. The optimalcondition: mass percent of dipping solution is10%, calcination temperatue is550℃;the pH value of reaction solution is3.5, the reaction temperature is60℃, catalystloading is6g/L and H2O2usage is110%stoichiometric amount. Under such condition, COD removal is above85%. The degradation of Acid brilliant scarlet3R solution followsthe first-order kinetics and the activation energy is47.45kJ/mol by calculation.Among other catalysts we prepared, Fe2O3/SiO2、CuO/SiO2catalysts have the bestcatalytic effect. The degradation ratio of Acid brilliant scarlet3R can reach92%, andCOD removal is above85%. This may be because of the low density and high surfacearea of the hollow catalysts.3. Bi-component catalysts CuO-CeO2/SiO2、CuO-Fe2O3/SiO2、CuO-MnO2/SiO2、CuO-ZnO/SiO2were also prepared by impregnation method. We studied the catalyticeffect of these catalysts on degradation reaction. The results show that the doping ofCe element reduces the leaching of Cu2+ion. The doping of Fe and Zn elementsimprove the degradation retio. Especially the Zn element can act as a promoter,mainly because Zn improves dispersion of CuO.