This project will benefit society by providing information that can enable a new approach to adsorptive removal of metals in drinking water. The project is focused on improved treatment of three contaminants, arsenic, uranium and chromium, which are of current interest both within the United States and internationally. Newly created information on magnetic iron oxide sorbents will not only enable their integration into sorption treatment technologies, but it will also benefit other particle-based environmental technologies related to sensing, imaging, and remediation. Systematic evaluation of sorbent regeneration and the properties of the residual solids will contribute to the life cycle assessments of processes that use new sorbents. The research plan will help train the future science and technology workforce through the involvement of high school, undergraduate, and Ph.D. students. In all educational activities, programs will be used to promote increased participation of underrepresented minorities.
The project will investigate a potentially transformative new approach to preparing tailored sorbent media for removal of metal and metalloids from drinking water. The platform approach uses engineered iron oxide nanoparticles with high surface areas and affinities for metal adsorption that can be controlled with respect to their aggregation and deposition on substrate supports. The project will advance scientific understanding of metal adsorption of arsenic, uranium and chromium to a novel set of engineered nanoparticles and the factors that control the properties of the nanoparticles and their interactions with supporting media. The project objectives are to: (1) develop model libraries of engineered iron oxide nanoparticles with controlled size, composition, and aqueous stabilities; (2) quantify the adsorption affinity and capacity of the new sorbents and elucidate adsorption mechanisms; (3) evaluate the performance and regeneration potential of sorbent media in realistic treatment configurations. The PIs will pursue these objectives through three integrated tasks. Task 1 they will develop a library of iron oxide nanoparticles with a range of surface coatings and particle sizes, and then characterize the stability of particle suspensions and their deposition to substrate media. Task 2 is a detailed investigation of the adsorption of arsenic, chromium, and uranium to the nanoparticles that will combine batch adsorption experiments, spectroscopic characterization of adsorbed metals, and surface complexation modeling of adsorption. Task 3 will evaluate the performance and regeneration of substrate-supported sorbent materials in continuous-flow column experiments. The research approach will be closely linked with education and outreach activities at their university and in their community.
