Title: “The Physics, Chemistry, and Topology Behind Particle Transport and Retention in Aqueous Saturated Porous Media”

Date: December 2, 2015
Time: 10:45 – 11:35 AM
Place: WEB L104

Particle transport and retention in environmental porous media underlies many environmental engineering contexts (e.g. recent presentation by Dr. Linda Abriola). However, a functioning theory to underlie prediction and design has been absent. This is because of inability of mechanistic models to predict particle attachment when repulsion exists between bulk negative- charged particles and porous media surfaces under environmental (unfavorable) conditions. It has long been suspected that particle attachment despite bulk repulsion occurs due to nanoscale zones of attraction emanating from charge heterogeneity or roughness (so called discrete heterogeneity). This talk examines the opportunities for mechanistic prediction offered by incorporation of representative discrete heterogeneity into mechanistic simulations.

Short Biography
Dr. William P. Johnson an environmental engineer who examines the transport and fate of contaminants in the environment with a focus on predicting particle transport in porous media (e.g. pathogens and particle-borne contaminants). He is a Professor in the Department of Geology & Geophysics (adjunct in Civil & Environmental Engineering). He was a post-doc in the Department of Chemical & Environmental Engineering U. of Arizona following his PhD in Civil Engineering (U. of Colorado), M.S. and B.S. in Geology from Dartmouth College and Whitman College, respectively. He has been principal investigator on more than ten federally funded research grants (predominantly National Science Foundation), and has led five state- funded projects examining the fate and transport of selenium and mercury in the Great Salt Lake and surrounding wetlands, and a recent project concerning bitumen-related compounds in the tar sands of eastern Utah. Dr. Johnson has produced more than 100 peer reviewed publications in top-tier journals, with over 3000 citations of this work to date.