Adhesion is a physicochemical process of great importance for various environmental engineering technologies including those that are employed in water treatment facilities. Understanding adhesion is the key to elucidating separation mechanisms in unit processes and operations such as flocculation, granular media filtration, membrane separation. The likelihood of adhesion can be quantified in terms of the interfacial energy of interaction between two objects.The first part of this dissertation is devoted to the study of virus adhesion to surfaces commonly encountered in various indoor settings. Fomites are inanimate surfaces, which can transfer the pathogens to a new human host. Fomite-based transfer is an important pathway of virus transmission, along with direct contact and transmission through aerosols. The study of fomites has traditionally focused on determining whether there is presence of specific pathogenic organisms. In addition to detecting genetic material and viable microbes on fomite surfaces, it is also important to understand the underlying mechanism of virus adhesion and factors that affect the likelihood of transmission between fomites and humans. In this dissertation, Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) is employed to quantify virus attachment to fomites. XDLVO modeling is applied to predict the virus-fomites interactions. Virion size, surface charge and surface energy components as well as surface charge and surface energy components of various fomites were measured and used as inputs to the XDLVO model.The second part of this dissertation describes the study of membrane filter aging due to membrane's intermittent exposure to foulants and cleaning agents. This study explores how the surface chemistry of polyvinylidene fluoride (PVDF) membranes evolves in challenge tests with humic acid (HA) fouling and sodium hypochlorite (NaClO) employed as a model foulant and cleaning agent, respectively. The evolution of physicochemical properties of the ageing membranes is characterized based on surface energy calculations. The results point to the formation of a chemically irreversible layer of foulants that is conditioned by consecutive exposures to foulants and is comprised of the adsorbed foulant fraction that is hard to oxidize further.
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