High Capacity Sorbent Development for Mercury Capture

A. BACKGROUND The U.S. Environmental Protection Agency requires the development of functionalized materials for mercury capture from both vapor and aqueous streams. The main goal ofthe project is the development and quantitative evaluation of high capacity mercury sorbents containing thiolbased polyfunctionalligands. The functionalization process optimization, material characterization and the correlation of surface functional density with mercury sorption is also required. B. TASKS 1. The contractor shall select macroporous and other nanoparticle aggregates, such as silicabased materials, and develop functionalization procedures for attaching polyfunctionalligands containing sulfur groups for vapor phase mercury sorption studies. The use and incorporation of noncyclic polysulfides shall also be evaluated. 2. The contraCftorshall evaluate inexpensive polymeric membranes, such as cellulose, and polymer-inorganic composite, such as silica/polyethylene, materials to attach thiol containing polymeric ligands at high density for aqueous phase mercury ion sorption applications. 3. The contractor shall perform, with Task (1) materials, various batch and continuous flow experiments with silp.ulated gases containing mercury vapor to establish both equilibrium and rate of sorption as a function of temperature and mercury vapor (:oncentrations. 4. The contractor shall perform, with Task (2) materials, convective flow experiments with single mercury salt and multi salt, to establish selectivity, experiments to establish sorption kinetics and selectivity data. 5. The contractor shall correlate the mercury sorption behavior with the extent of functional groups and surface area of materials. The material usage requirements, temperature limitations, for vapor sorption use, and the mode of contact regarding scale-up shall be incorporated as part of the process optimization work.