Microporous coordination polymers (MCPs) are extended crystalline networks of a metal or of metal clusters linked by organic molecules, with potential application in areas such as gas sorption, separations, catalysis, and large molecule storage and transport. In particular, the removal of sulfur from fuels is also important because onboard reforming of fuels to hydrogen in hydrogen fuel cell vehicles can be achieved by the use of metal catalysts. However, such catalysts are poisoned by levels of sulfur >0.1 ppm. Currently, the most common way to remove organosulfur compounds from fuel is a technique called hydrodesulfurization (HDS). In this technique, a catalyst, typically molybdenum sulfide promoted by cobalt or nickel, is used to hydrogenate and break apart the undesirable compound. The resulting hydrogen sulfide is easier to remove than the original sulfur-containing compound. Although HDS effectively removes alkyl sulfides and small aromatic organosulfur compounds from fuels, this technique is not efficient at removing larger aromatic organosulfur compounds due to their unreactivity. As diesel is rich in large organosulfur compounds, motivating the development of alternative removal strategies.
Researchers at the University of Michigan have developed adsorbents for removal of organosulfur compounds from fluids. In particular, the organosulfulr-containing liquid such as gasoline, diesel, or jet fuel, is contacted with the microporous coordination polymer to form a MCP-organosulfur inclusion compound. In addition, a sorbent bed including MCP, adapted to remove sulfur-containing compounds from a liquid, is provided. The sorbent bed may be regenerated at various temperatures by passing a fluid through the sorbent bed to remove adsorbed organosulfur compounds. MCPs are particularly attractive for this application because of the ability to tailor the linker and/or metal of an MCP to allow organosulfur removal.
Applications and Advantages
- Removal of organosulfur compounds from fluids.
- More energy efficient and practical than presently available techniques, leading to cost and time savings.