Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $20,000 Total Non-Federal Funds: $40,000
Principal Investigators: Lei Zhang
Abstract: Mining in Alaska affects many fresh water sources through heavy use of water in processing ore, and water pollution from discharged mine effluent and seepage from tailings and waste rock impoundments. Heavy metal pollution is caused when metals, such as arsenic, nickel, lead, cadmium, cobalt, copper, silver and zinc, contained in excavated rock or exposed in an underground mine come in contact with water. These heavy metals could be harmful to those who drink the water, as they are not biodegradable and can accumulate in living tissues, posing great threat to both human health and the ecological environment. While there have been improvements to mining practices in recent years, significant environmental risks remain that can affect the availability of clean drinking water resources in rural and remote Alaskan communities. Thus, it is imperative to develop efficient methods to remove heavy metals from contaminated waters. Numerous methods have been proposed to efficiently remove heavy metals from wastewater, including but not limited to chemical precipitation, ion exchange, adsorption, and membrane filtration. Among these techniques, adsorption is one of the most promising methods because it is simple, highly effective, and economical. Numerous adsorbents, including carbon-based materials, metal oxides, and biomass, have been explored. However, further applications of these materials are limited by their low adsorption capacities, low efficiencies, or high cost. Novel nanomaterials offer myriad opportunities for water treatment thanks to their excellent surficial and chemical properties at the micro-nano scale. One such novel nanomaterial, graphene, discovered in 2004, is a sheet of carbon atoms just one atom thick and is said to be the strongest material ever measured. With its excellent thermal, electrical and chemical properties, it is being dubbed the find of the twenty-first century and is predicted to revolutionize the fields of engineering and technology. A commonly used derivative of graphene nanoparticles in water treatment is a sheet form known as graphene oxide (GO). However, GO tends to aggregate, which decreases its available surface area and adsorption capacity. Functionalization of GO with molecules that have affinity toward target analytes will improve the selectivity of adsorbents, as well as prevent aggregation. Epoxy, carboxyl and hydroxyl functional groups on either side of the GO offer the possibility of a two-dimensional (2D) nanoscale building block that can participate in a supramolecular assembly to form new hybrids. Metal-organic frameworks (MOFs), another class of nanoparticles with lightweight, ultra-high surface areas and tunable structures, can be incorporated with GO to form a MOF-GO nanocomposite, thus overcoming the aggregation of GO in aqueous solution and further increasing the surface area. Herein, we propose to develop a MOF-GO nanocomposite for innovative water treatment. In particular, we propose to: (1) synthesize MIL-53(Al)-GO nanocomposite and characterize its crystal structure and surface area, (2) explore the relationship of the adsorption capacity of heavy metal ions (As(V), Ni(II), and Pb(II)) as a function of the mass ratio of MIL-53(Al) in MIL-53(Al)-GO, and (3) develop adsorption isotherm models and measure the kinetics of heavy metal removal on MIL-53(Al)-GO.