Tian Cheng Liu

Adsorption Thermodynamics Study on CCl2F2 over Solid Base Na2O/ZrO2

Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over solid base Na2O/ZrO2 using a fixed-bed reactor. The CCl2F2 adsorption was multilayer chemical adsorption and its process was corresponding with Freundlich model. Its adsorption heat was from 43.74 to 76.31 KJ.mol-1, and the CCl2F2 adsorption over solid base Na2O/ZrO2 was exothermic and chemical.

Reaction Mechanism for CCl2F2 Catalytic Decomposition over MoO3/ZrO2

Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over a series of solid acids using a fixed-bed reactor. Solid acid MoO3/ZrO2 displayed the highest activity, over which the conversion of CCl2F2 reached 100 % at 250 °C. CO2 was the main-product and the selectivity to CClF3 remained lower than 28.0 %. CO was not detected as by-product. The decomposition activity depended on the calcination temperature and the ZrO2 content. The activity of solid acid MoO3/ZrO2 correlates well with its specific surface area and the amount of medium-strong acid sites on the surface. To explain the reaction mechanism for CCl2F2 catalytic decomposition over MoO3/ZrO2, a surface intermediate, Osurface-CF2-Osurface is proposed.

Chrysotile-Asbestos Decomposition by CCl2F2-Decomposed Acidic Gas

Asbestos was widely used in numerous materials and building products duo to its desirable properties. However, it is well known that asbestos inhalation causes health damage and its inexpensive decomposition technique is necessary to be developed for pollution prevention. Dichlorodifluoromethane (CCl2F2) must be decomposed before being liberated into the atmosphere. Acidic gas (HF and HCl) generated from the decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen, was reacted with chrysotile-asbestos fibers. At high temperature beyond 300 °C, chrysotile-asbestos fibers were completely decomposed, and sellaite and hematite were detected in the decomposed products.

Kinetics Study on Catalytic Hydrolysis of CCl2F2 over Solid Acid MoO3/ZrO2

Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over solid acid MoO3/ZrO2 using a fixed-bed reactor. The adsorption velocity equation was calculated by Bangham Equation. Reaction energy was determined by Arrhenius Equation and it was 123.12 KJ.mol-1.

Thermodynamics Study on Catalytic Hydrolysis of CCl2F2 over Solid Acid MoO3/ZrO2

Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over solid acid MoO3/ZrO2 using a fixed-bed reactor. The CCl2F2 adsorption was multilayer chemical adsorption and its process was corresponding with Freundlich model. Its heat was from 56.3 to 73.2 KJ.mol-1, and it was exothermic reaction and chemical adsorption.

Catalytic Hydrolysis of CCl2F2 over Solid Base CaO/ZrO2

Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over a series of solid base that have different ZrO2 content using a fixed-bed reactor. CO2 and CClF3 were the main-products and no CO was detected as by-product. The decomposition activity depended on the calcination temperature and the Zr:Ca. Calcined at 650 °C and Zr:Ca=1:0.35 were the best catalyst preparation conditions. Adopting low concentration of oxygen and CCl2F2 and high concentration of water vapor is preferable to the achievement of high conversion of CCl2F2 and selectivity for CO2. The catalytic activity of CaO/ZrO2 remained steady for 20 h on stream.

Catalytic Decomposition of CCl2F2 over Solid Base Na2O/ZrO2

Catalytic decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over a series of solid base that have different ZrO2 content using a fixed-bed reactor. CO2 and CClF3 were the main-products and no CO was detected as by-product. The decomposition activity depended on the calcination temperature and the Zr:Na. Calcined at 600 °C and Zr:Na=1:0.35 were the best catalyst preparation conditions. Adopting low concentration of oxygen and CCl2F2 and high concentration of water vapor is preferable to the achievement of high conversion of CCl2F2 and selectivity for CO2. The catalytic activity of Na2O/ZrO2 remained steady for 120 h on stream.