Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Synthetic molecular sieve binds water better than zeolites

24.09.2002


Zeolites are an extremely important class of inorganic materials that can separate gases or liquids on the basis of molecular size and shape. The backbone of a billion-dollar-a-year industry, these molecular sieves are used in numerous applications, from the production of biodegradable detergents, to the removal of moisture from natural gas pipelines, to the catalytic cracking of heavy petroleum distillates into gasoline.



Now, chemist Kenneth S. Suslick and colleagues at the University of Illinois at Urbana-Champaign have created a new class of materials that are like zeolites in many ways. These new molecular solids are more than 50 percent empty space ­ space that can trap molecules of the right size and shape, including water. The scientists report their discovery in a paper that has been accepted for publication in the journal Nature Materials, and posted on its Web site www.nature.com/materials.

"This organic zeolite analogue binds water faster and more strongly than the best drying agents and has a higher capacity for storing water," said Suslick, a William H. and Janet Lycan Professor of Chemistry at Illinois. "The material also shows shape selectivity, permitting only a narrow range of molecules to enter."


A naturally occurring mineral consisting of aluminum and silicon, zeolites were discovered in the Middle Ages. At the time, the properties of a material were tested by heating it with a blowpipe. When this material was heated, boiling water was released. The name zeolite is derived from Greek words meaning "boiling stone."

The ability to make other kinds of molecular sieves has been a major goal in materials chemistry. That goal has been frustrated, however, because most solids are not porous to begin with, and the process of generating pores causes most materials to collapse.

To build robust nanoporous solids that are not based on silica and alumina, the researchers used much larger molecular building blocks called metalloporphyrins ­ doughnut-shaped molecules that bind metal atoms in the middle hole. Metalloporphyrins are closely related to hemoglobin (the red pigment in blood) and chlorophyll (the green pigment in plants).

By heating a mixture of a special porphyrin acid and cobalt chloride to 200 degrees Celsius, Suslick and his colleagues created a compound called PIZA-1 (Porphyrinic Illinois Zeolite Analogue #1).

"PIZA-1 demonstrated remarkable properties as a synthetic molecular sieve for removing water from common organic solvents," Suslick said. "In addition, because the metalloporphyrin has a metal in the middle that can be catalytically active, the potential exists to make shape-selective catalysts for specific purposes. Not only can we selectively absorb molecules into the solid, we can also make the trapped molecules undergo chemical reactions ­ such as the catalytic oxidation of fuels."

Catalytic reactions that would convert the hydrocarbons in gasoline into the chemicals that react to make polymers such as nylon are not yet possible to achieve, Suslick said. "But the ability to use fossil fuels as chemical feedstocks, rather than just burning them, is a technology that will become very important this century."

Collaborators on the project were graduate student Margaret Kosal (now at Chem Sensing), postdoctoral researcher Jun-Hong Chou (now at Dupont), and X-ray crystallographer Scott Wilson. The National Institutes of Health and the U.S. Department of Energy funded the work.

James E. Kloeppel | News Bureau, UIUC
Further information:
http://www.news.uiuc.edu/scitips/02/0923sieve.html

More articles from Life Sciences:

nachricht Water world
20.11.2017 | Washington University in St. Louis

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>