RIMI: Titanium Dioxide Catalyzed Photodegradation of Organophosphorous Compounds: A Kinetic and Mechanical Study

将仔细监测和评估tio2催化的有机磷化合物的光降解，以确定该过程的动力学参数。这些动力学参数对于评价和预测多组分体系中有机磷化合物降解的总体速率和效率以及反应器设计具有重要意义。初始底物和在这些反应中形成的产物之间的质量平衡将用于确定矿化程度。在整个降解过程中形成的反应中间体和产物的表征将用于确定反应的过程。在光催化过程中形成羟基自由基、超氧阴离子和过氧化氢，每个物种将独立生成，与模拟物反应后的产物分布确定。羟基自由基、超氧阴离子和过氧化氢的特征产物分布将与tio2催化光反应中观察到的产物进行比较，以确定这些中间体在tio2催化光降解中的作用和参与程度。由于溶液pH、溶解氧浓度和反应副产物对降解过程有显著影响，因此将对这些因素进行深入研究。还将评估使用添加剂来加速这一过程。这些研究将为控制有机磷化合物在光激发TiO2上的化学反应活性的因素提供基本的理解。从拟议的调查中获得的信息将直接应用于半导体催化光氧化作为对环境威胁的有机磷化合物（如化学战剂和农药）解毒的手段的优化和评价。如果得到支持，该项目将对TiO2光催化过程的基本理解以及几个少数民族在化学和环境科学方面的专业发展产生重大影响。1名少数民族教师，4-5名本科生（其中3名目前计划在完成学士学位后攻读化学博士学位）和2名硕士生将直接参与拟议的项目。这项支持将使少数族裔参与pi实验室的人数增加50%。＊＊＊

9550712 O'Shea The Ti02 catalyzed photodegradation of the organophosphorus compounds will be carefully monitored and evaluated to determine the kinetic parameters for the process. These kinetic parameters are of importance in evaluating and predicting overall rates and efficiencies for the degradation of organophosphorus compounds in multi-component systems and for reactor design. The mass balance between the initial substrates and the products formed during these reactions will be used to determine the degree of mineralization. Characterization of the reaction intermediates and products formed throughout the course of the degradation will be used to establish the course of the reactions. Hydroxyl radical, superoxide anion, and hydrogen peroxide are formed during the photocatalytic process, each species will be independently generated and the product distribution upon reaction with the simulants determined. The characteristic product distributions for hydroxyl radical, superoxide anion, and hydrogen peroxide will be compared to those observed for the Ti02 catalyzed photo-reactions to establish the role and involvement of these intermediates in the Ti02 catalyzed photodegradation. Since the solutions pH, dissolved oxygen concentration, and reaction byproducts can dramatically effect the degradation process, these factors will be thoroughly investigated. The use of additives to accelerate the process will also be evaluated. These studies will provide a fundamental understanding of the factors governing the chemical reactivity of organophosphorus compounds on photoexcited TiO2. The information obtained from the proposed investigations will find direct application in the optimization and evaluation of semiconductor catalyzed photooxidation as a means of detoxification of environmentally threatening organophosphorus compounds, such as chemical warfare agents and pesticides. If supported this project will have a substantial impact on the fundamental understa nding of the processes involved in TiO2 photocatalysis and the professional development of several minorities into the chemical and environmental sciences. One minority faculty member, 4-5 undergraduate students (three which currently plan to pursue a Ph.D. in Chemistry upon completion of their BS degrees) and 2 masters students will be directly involved in the proposed project. Support will increases minority participation in the PIs' laboratories by 50%. ***