【作者】 李晓红；

【导师】 徐自力；

【作者基本信息】 吉林大学 ， 环境科学， 2005， 硕士

【摘要】 本文以钛酸丁酯为前驱体,利用溶胶-凝胶法制备了TiO₂-SiO₂复合纳米粒子粉末,用TiO₂/SiO₂复合纳米粒子对有机污染物（甲苯、庚烷、SO₂、NO₂、NO）进行降解。以TiO₂/SiO₂复合纳米粒子为催化剂,研究了甲苯的初始浓度、氧气和水蒸气的不同含量、光强及其SO₂ 等因素对其光催化氧化降解的影响。采用兰缪尔-欣伍德（Langmuir-Hinshelwood）动力学模型得到了甲苯光催化降解的反应速率常数和吸附常数,并且用GC、GC-MS、FT-IR 初步确定了反应产物。以TiO₂/SiO₂复合纳米粒子为催化剂,对C₇H₁₆-O₂-TiO₂/SiO₂、SO₂-O₂-TiO₂/SiO₂ 和C₇H₁₆-SO₂-O₂-TiO₂/SiO₂ 三个体系进行了研究。分别用GC、GC-MS、FT-IR 对反应物、反应中间产物进行了初步分析。以TiO₂/SiO₂复合纳米粒子为催化剂,对C₇H₁₆-O₂-TiO₂/SiO₂、C₇H₁₆-NO₂-O₂-TiO₂/SiO₂、C₇H₁₆-NO-O₂-TiO₂/SiO₂ 三个体系进行了研究。分别用GC、GC-MS、FT-IR 对反应物、反应中间产物进行初步分析,并初步探讨了反应的氧化机制。更多还原

【Abstract】 In 1972, Fujishima discovered the photocatalytic splitting of water on TiO₂ electrodes. Since then, research efforts in understanding the fundamental processes and in enhancing the photocatalytic efficiency of TiO₂ have come from extensive research performed by chemists and physicists. Photocatalysis is rapidly developing in recent years, and it has been a promising process for remediation environmental air pollution by volatile organic compounds. At moderate conditions （room temperature, one atmosphere pressure and with molecular oxygen as the only oxidant）, the above mentioned semiconductors have proved to be effective photocatalysts for the dynamically favored transformations of many organic compounds to CO₂ and H₂O. In this paper, firstly we prepare the supported catalyst by using a sol-gel method. TBOT and TEOS as crude materials proceed hydrolytic decomposition and condensation polymerization in the organic mediator （ammonia liquor）, after sol-gel and drying process the particle is calcined at 600℃. Composited TiO₂/SiO₂ catalyst have lots of merits of photoresponse red shift, delayed recombination, high-catalysis activity, large specific surface area, greatly adsorpted organic matter than TiO₂. Secondly, This investigation concerned the photocatalytic oxidation of toluene over TiO₂/SiO₂ in the gas-phase. The feasibility studies involved the effects of initial concentration of reactant, oxygen content, water vapor content and light intensity on the photocatalytic reaction. The photocatalytic degradation rate increased with increasing the initial concentration of toluene, but maintained almost constant beyond a certain concentration. It matched well with the Langmuir-Hinshelwood kinetic model. The reaction rate increased with increasing oxygen content, but for higher than 18%（v/v）, the reaction rate reversed. For the influence of water vapor in the gas-phase photocatalytic degradation rate of toluene, there was an optimum concentration of water vapor （0.2%（v/v））. The photocatalytic degradation rate increased with light intensity but the rate approached to level off when the light intensity rose to 3mW/cm2. The photocatalytic degradation rate constant and the adsorption constant of toluene were obtained using the Langmuir-Hinshelwood model, and the reaction products （CO2, benzoic acid, phenyl--aldehyde, benzyl alcohol, micro-content benzene） were also identified by FI-RT and GC-MS. Thirdly, we study different system about heptane and SO2,heptane and NOx （NO2、NO） over TiO2-SiO2 catalyst. In the photocatalytic reaction process of C7H16-O2-TiO2/SiO2 and SO2-O2-TiO2/SiO2, degradation of SO2 is faster than heptane and its agree first-order reaction. In the reaction process of SO2-C7H16-O2-TiO2/SiO2, the structure of SO42-/TiO2-SiO2 formed on the surface of TiO2-SiO2 enhanced the rate of photocatalytic oxidation of hepane and it wad studied using IR. In SO2-C7H16-O2-TiO2/SiO2 system, returns on investment of heptane is the best when oxygen更多还原