There is perhaps no greater challenge faced by drinking water utilities in the United States than meeting disinfection byproduct regulations for trihalomethanes and haloacetic acids. Formation of these regulated chemicals and other potentially toxic disinfection byproducts, such as n-nitrosodimethylamine, is expected to increase as water utilities continue to exploit source waters impacted by algal blooms and wastewater discharges. Fortunately, the burgeoning field of nanotechnology offers promise. Specifically, properties of carbon nanotubes suggest they may have substantial adsorption capacities for disinfection byproducts precursors, which could be further enhanced by manipulating carbon nanotube surface chemistry. The objective of this research project is to reengineer the tunable physicochemical properties of carbon nanotubes for enhanced adsorption of disinfection byproduct precursors. A systematic reductionist approach will be employed to modify physical (e.g., surface area, pore size distribution) and chemical (e.g., surface functional groups, surface charge) properties of carbon nanotubes for enhanced adsorption of trihalomethane, haloacetic acid, and n-nitrosodimethylamine precursors. Equilibrium adsorption capacities of the reengineered carbon nanotubes will be measured in batch isotherm experiments. Kinetic limitations will be assessed using rapid small-scale column tests to determine suitable processes within drinking water treatment plants for carbon nanotube integration. The extent to which direct gasification can regenerate spent carbon nanotubes will be assessed to address cost considerations. Fundamental characterizations of the reengineered carbon nanotubes and disinfection byproduct precursors (e.g., elemental composition by Fourier transform ion cyclotron resonance mass spectroscopy) will facilitate development of structure-property relationships, thus permitting broad applicability of the research findings. The expected outcome of this research is a systematic procedure to fundamentally reengineer carbon nanotubes for enhanced adsorption of disinfection byproduct precursors.
A major challenge for many drinking water utilities in the United States is achieving adequate disinfection while limiting formation of disinfection byproducts. As waters become more impaired due to the trickle down impacts of population growth, significant advancements in the removal of disinfection byproduct precursors are critically needed. In this research project, principles of nanotechnology, surface chemistry, and analytical chemistry are leveraged to reengineer carbon nanotubes for effective uptake of disinfection byproduct precursors. This discovery could spur vast improvements in the treatment of the nations drinking water supply and reduce concentrations of disinfection byproducts at the tap.
