"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."
0854416 Crittenden
Advanced oxidation processes (AOPs) have shown promise to destroy many of the emerging organic contaminants in water, and are being considered in potable water treatment, wastewater treatment, site remediation, and industrial applications. AOPs are mechanistically complex in nature and are difficult and expensive to study experimentally relative to the degradation kinetics and pathways of each contaminant and the fate of the intermediates and byproducts. With more than 90,000 organic chemicals produced annually, the increasing concerns about emerging contaminants make the need for an analytical computational tool more urgent. The principal objective of this project is to develop computational tool of predicting reaction pathways that are involved in the AOPs. The fundamental approach is to represent chemical molecules numerically and to enumerate the reaction possibilities using a numerical algorithm. Graph theory will be applied as a basic methodology for species formation and reaction generation. The reactants and reaction types are expressed by a two dimensional matrix called the bond and electron matrix. Manipulating the matrices of reactants and the products according to reaction rules generates the reaction pathway network. The risks of all the intermediates and byproducts will be screened. Quantum theory and quantitative structure-activity relationships (QSARs) will be applied to estimate the rate constants for the reaction pathway network. An algorithm will be developed to write and solve the ordinary differential equations that comprise the reaction pathway to predict the concentration time profile of each species. The model will be validated using several case studies that have been reported in the literature. A new ASU supercomputer facility will be used to aid in simulating reaction schemes, rate constants, and toxicity.
The proposed project is a step towards building a comprehensive pathway generator. The ultimate goal of this effort would be to predict the fate of all byproducts that are formed in complex oxidation reaction systems. The broader impact of the generator includes: 1) providing a tool for better understanding of chemical reaction mechanisms that potentially could be extended to other systems; 2) predicting the formation of trace byproducts in chemical oxidation processes; 3) providing an excellent complementary tool for risk screening of all the byproducts, and helping select more environmentally-friendly oxidants and chemical treatment processes; 4) providing a comprehensive interdisciplinary teaching and training tool for students to study the chemical kinetics of processes that include the formation of intermediates; and, 5) providing chemical insight so that time consuming experimental mechanistic studies can be planned carefully. As part of this project, The PIs will develop course modules that will be able to provide chemical intuition for complex radical chemistry reactions.
