Designed by Northwestern University chemists, it can remove mercury from polluted water, easily separate hydrogen from other gases and, perhaps most impressive of all, is a more effective catalyst than the one currently used to pull sulfur out of crude oil.
Hydrodesulfurization might be a mouthful, but it is also a widely used catalytic chemical process that removes sulfur from natural gas and refined petroleum products, such as gasoline and diesel and jet fuels. Without the process, which is highly optimized, we'd be burning sulfur, which contributes to acid rain.
Scientists have tried to improve hydrodesulfurization, or HDS, but have made no progress. Many consider it an optimized process. The Northwestern researchers, in collaboration with colleagues at Western Washington University, report that their material is twice as active as the conventional catalyst used in HDS while at the same time being made of the same parts.
The material, cobalt-molybdenum-sulfur, is a new class of chalcogels, a family of material discovered only a few years ago at Northwestern. (Chalcogels are random networks of metal-sulfur atoms with very high surface areas.) The new chalcogel is made from common elements, is stable when exposed to air or water and can be used as a powder.
Details of the cobalt-molybdenum-sulfur chalcogel and its properties will be published online May 17 by the journal Nature Chemistry. This is the first report of chalcogels being used for catalysis and gas separation.
"I was surprised at the impressive activity of our catalyst, given how difficult it has been to improve HDS," said Mercouri G. Kanatzidis, the paper's senior author. "In principle, our catalyst could process and desulphurize twice as much crude oil as the same amount of conventional catalyst. We currently are conducting studies to see how the catalyst operates under more commercial conditions."
Kanatzidis, Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences, and doctoral student Santanu Bag make their catalyst using a method different from that of the conventional catalyst.
The Northwestern material is a gel made of cobalt, nickel, molybdenum and sulfur that then is freeze-dried, producing a sponge-like material with a very high surface area. (One cubic centimeter has approximately 10,000 square feet of surface area, or about half a football field.) It is this high surface area and the material's stability under catalytic conditions that make the cobalt-molybdenum-sulfur chalcogel so active.
The researchers also demonstrated that the new chalcogel soaks up toxic heavy metals from polluted water like no other material. The chalcogel removed nearly 99 percent of the mercury from contaminated water containing several parts per million. Mercury likes to bind to sulfur, and the chalcogel is full of sulfur atoms.
Two years ago, Kanatzidis and Bag reported a chalcogel that could remove mercury from liquid, but the chalcogel contained expensive platinum; the new chalcogel contains only inexpensive elements, with cobalt and nickel replacing the platinum. The cobalt and nickel link through the sulfur atoms of the thiomolybdate anions to create a three-dimensional porous network.
"We succeeded in doing something very difficult: eliminating the platinum and only using common materials to create a gel," said Kanatzidis. "We found the proper conditions to get the properties we wanted. The key was changing the solvent from water to formamide."
In addition to being a better HDS catalyst and a mercury sponge, the chalcogel also is very effective at gas separation. The researchers showed that the material easily removes carbon dioxide from hydrogen, an application that could be useful in the hydrogen economy.
The gas separation process takes advantage of the 'soft' sulfur atoms of the chalcogel's surface. These atoms like to interact with other soft molecules passing by, slowing them down as they pass through. Hydrogen, the smallest element, is a 'hard' molecule. It zips right through while softer molecules like carbon dioxide take more time.
The Nature Chemistry paper is titled "Spongy Chalcogels of Nonplatinum Metals Act as Effective Hydrodesulfurization Catalysts." In addition to Kanatzidis and Bag, the paper's other authors are chemistry professor Mark E. Bussell and graduate student Amy F. Gaudette of Western Washington University.
Megan Fellman | EurekAlert!
Further reports about: > HDS > Hydrodesulfurization > Hydrogen > Nature Immunology > Sulfur > carbon dioxide > catalytic chemical process > chalcogel > cobalt-molybdenum-sulfur chalcogel > jet fuels > metal-sulfur atoms > natural gas > petroleum products > polluted water > sponge-like material > surface area
Fingerprint' technique spots frog populations at risk from pollution
27.03.2017 | Lancaster University
Parallel computation provides deeper insight into brain function
27.03.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
27.03.2017 | Earth Sciences
27.03.2017 | Life Sciences
27.03.2017 | Life Sciences