title: On-the-Fly Kinetic Monte Carlo Simulation of Aqueous Phase Advanced Oxidation Processes.
abstract: We have developed an on-the-fly kinetic Monte Carlo (KMC) model to predict the degradation mechanisms and fates of intermediates and byproducts that are produced during aqueous-phase advanced oxidation processes (AOPs). The on-the-fly KMC model is composed of a reaction pathway generator, a reaction rate constant estimator, a mechanistic reduction module, and a KMC solver. The novelty of this work is that we develop the pathway as we march forward in time rather than developing the pathway before we use the KMC method to solve the equations. As a result, we have fewer reactions to consider, and we have greater computational efficiency. We have verified this on-the-fly KMC model for the degradation of polyacrylamide (PAM) using UV light and titanium dioxide (i.e., UV/TiO2). Using the on-the-fly KMC model, we were able to predict the time-dependent profiles of the average molecular weight for PAM. The model provided detailed and quantitative insights into the time evolution of the molecular weight distribution and reaction mechanism. We also verified our on-the-fly KMC model for the destruction of (1) acetone, (2) trichloroethylene (TCE), and (3) polyethylene glycol (PEG) for the ultraviolet light and hydrogen peroxide AOP. We demonstrated that the on-the-fly KMC model can achieve the same accuracy as the computer-based first-principles KMC (CF-KMC) model, which has already been validated in our earlier work. The on-the-fly KMC is particularly suitable for molecules with large molecular weights (e.g., polymers) because the degradation mechanisms for large molecules can result in hundreds of thousands to even millions of reactions. The ordinary differential equations (ODEs) that describe the degradation pathways cannot be solved using traditional numerical methods, but the KMC can solve these equations.
authors.affiliation: †School of Civil and Environmental Engineering, Georgia Institute of Technology, 828 West Peachtree Street, Atlanta, Georgia 30332, United States.
authors.forename: Xin
authors.initials: X
authors.lastname: Guo
authors.affiliation: ‡Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49931, United States.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Minakata
authors.affiliation: †School of Civil and Environmental Engineering, Georgia Institute of Technology, 828 West Peachtree Street, Atlanta, Georgia 30332, United States.
authors.forename: John
authors.initials: J
authors.lastname: Crittenden
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D003198:Computer Simulation; D007700:Kinetics; D008962:Models, Theoretical; D009010:Monte Carlo Method; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D013997:Time Factors; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry*; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D002244:Carbon; D014025:Titanium; D014867:Water; D000099166:Polyacrylamides; C009495:titanium dioxide