Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Organic Solvent System May Improve Recycling of Catalysts

Organic aqua regia; gold background - Researcher Wei Lin holds a beaker containing a gold/organic aqua regia solution. The image on the monitor shows gold recovered from the solution using calcinations. (Credit: Gary Meek)
Organic aqua regia; gold background - Researcher Wei Lin holds a beaker containing a gold/organic aqua regia solution. The image on the monitor shows gold recovered from the solution using calcinations. (Credit: Gary Meek)

Abstract:
Researchers at the Georgia Institute of Technology have developed a new organic solvent process that may help address the problem -- and open up new possibilities for using these metals in cancer therapeutics, microelectronics and other applications.

Organic Solvent System May Improve Recycling of Catalysts

Atlanta, GA | Posted on November 2nd, 2010

Noble metals such as platinum and palladium are becoming increasingly important because of growth in environmentally friendly applications such as fuel cells and pollution control catalysts. But the world has limited quantities of these materials, meaning manufacturers will have to rely on efficient recycling processes to help meet the demand.

Existing recycling processes use a combination of two inorganic acids known as "aqua regia" to dissolve noble metals, a class of materials that includes platinum, palladium, gold and silver. But because the metals are often dissolved together, impurities introduced in the recycling process may harm the efficiency of catalysts produced from the recycled materials. Now, researchers at the Georgia Institute of Technology have developed a new organic solvent process that may help address the problem -- and open up new possibilities for using these metals in cancer therapeutics, microelectronics and other applications.

The new Georgia Tech solvent system uses a combination of two chemicals -- thionyl chloride and a variety of organic reagents such as pyridine, N,N-dimethylformamide (DMF), pyrimidine or imidazole. The concentrations can be adjusted to preferentially dissolve gold or palladium, and more importantly, no combination of the organic chemicals dissolves platinum. This ability to preferentially dissolve noble metals creates a customized system that provides a high level of control over the process.

"We need to be able to selectively dissolve these noble metals to ensure their purity in a variety of important applications," said C.P. Wong, a Regents professor in the Georgia Tech School of Materials Science and Engineering. "Though we don't fully understand how it works yet, we believe this system opens a lot of new possibilities for using these metals."

A paper describing the research was published recently in the journal Angewandte Chemie.

Catalyst systems that make use of more than one metal, such as palladium with a gold core, are becoming more widely used in industrial processes. To recycle those, the new solvent system -- dubbed "organic aqua regia" -- could first use a combination of thionyl chloride and DMF to dissolve out the gold, leaving hollow palladium spheres. Then the palladium spheres could be dissolved using a different combination.

So far, the researchers have demonstrated that the solvent system can selectively dissolve gold and palladium from a mixture of gold, palladium and platinum. They have also used it to remove gold from a mixture of gold and palladium.

Beyond recycling, the new solvent system could also provide new ways of producing nanometer-scale cancer chemotherapy agents that involve these metals. And the new solvent approach could have important implications for the electronics industry, which uses noble metals that must often be removed after specific processing steps. Beyond selectivity, the new approach also offers other advantages for electronics manufacturing -- no potentially harmful contamination is left behind and processing is done under mild conditions.

"In semiconductor production, people want to avoid having a metal catalyst remaining in devices, but in many cases, they cannot use existing water-based processes because these can damage the semiconductor oxides and introduce contamination with free ions in the aqueous solution," explained Wei Lin, a graduate research assistant in Wong's laboratory. "Use of this organic system avoids the problem of moisture."

Use of the selective process could also facilitate recycling of noble metals used in electronics manufacturing. Wire-bonding, metallization and interconnect processes currently use noble metals.

Noble metals are also the foundation for widely-used chemotherapy agents, but the chemistry of synthesizing them involves a complex process of surfactants and precursors. Wong believes the new Georgia Tech solvent process may allow creation of novel compounds that could offer improved therapeutic effects.

"We hope this will open up some new ways of making these important pharmaceutical compounds as well as novel gold and palladium catalytic systems," he said.

Lin discovered the new solvent system by accident in 2007 while using thionyl chloride in an unrelated project that involved bonding carbon nanotubes to a gold substrate. "I left my sample in the solution and went to lunch," he recalled. "Then I received a couple of phone calls and the sample stayed in the solution for too long. When I got it out, the gold was gone."

The researchers were intrigued by the discovery and pursued an explanation as they had time over the past three years. They tested other reagents mixed with the thionyl chloride, and learned the proportions necessary for selective dissolution of palladium and gold. They worked with other researchers at Georgia Tech, including nanotechnology pioneer Zhong Lin Wang, to develop a fundamental understanding of the process -- research that is continuing.

The chemicals used by the Georgia Tech research team are well known in organic chemistry, and are used today in polymer synthesis. Beyond their selectivity, the new solvent system is more environmentally friendly than traditional aqua regia -- which is a combination of concentrated nitric and hydrochloric acids -- and can operate at mild conditions. Potential disadvantages compared to traditional aqua regia include higher costs and slower dissolution rates.

"We have opened up a new approach to noble metals using organic chemistry," Wong added. "We don't yet thoroughly understand the mechanism by which this works, but we hope to develop a more complete understanding that may lead to additional applications."

In addition to those already mentioned, the research team included Rong-Wei Zhang, Seung-Soon Jang and Jung-Il Hong, all from the School of Materials Science and Engineering at Georgia Tech.

####

For more information, please click here

Contacts:
Media Relations Assistance
John Toon
404-894-6986


Abby Vogel Robinson
404-385-3364


Copyright © Georgia Institute of Technology

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

GLOBALFOUNDRIES and Chengdu Partner to Expand FD-SOI Ecosystem in China: More than $100M investment to establish a center of excellence for FDXTM FD-SOI design May 23rd, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Leti Will Demo World’s-first WVGA 10-µm Pitch GaN Microdisplays for Augmented Reality Video at Display Week in Los Angles: Invited Paper also Will Present Leti’s Success with New Augmented Reality Technology That Reduces Pixel Pitch to Less than 5 Microns May 22nd, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Chemistry

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

Sandia develops math techniques to improve computational efficiency in quantum chemistry May 5th, 2017

Metal nanoparticles induced visible-light photocatalysis: Mechanisms, applications, ways of promoting catalytic activity and outlook April 27th, 2017

Shedding light on the absorption of light by titanium dioxide April 14th, 2017

Possible Futures

GLOBALFOUNDRIES and Chengdu Partner to Expand FD-SOI Ecosystem in China: More than $100M investment to establish a center of excellence for FDXTM FD-SOI design May 23rd, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Leti Will Demo World’s-first WVGA 10-µm Pitch GaN Microdisplays for Augmented Reality Video at Display Week in Los Angles: Invited Paper also Will Present Leti’s Success with New Augmented Reality Technology That Reduces Pixel Pitch to Less than 5 Microns May 22nd, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Academic/Education

MIT Energy Initiative awards 10 seed fund grants for early-stage energy research May 4th, 2017

Bar-Ilan University to set up quantum research center May 1st, 2017

California Research Alliance by BASF establishes more than 25 research projects in three years April 26th, 2017

SUNY Polytechnic Institute Announces Total of 172 Teams Selected to Compete in Solar in Your Community Challenge: Teams from 40 states, plus Washington, DC, 2 Territories, and 4 American Indian Reservations, Will Deploy Solar in Underserved Communities April 20th, 2017

Nanomedicine

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Sensors detect disease markers in breath May 19th, 2017

Oddball enzyme provides easy path to synthetic biomaterials May 17th, 2017

The brighter side of twisted polymers: Conjugated polymers designed with a twist produce tiny, brightly fluorescent particles with broad applications May 16th, 2017

Discoveries

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Sensors detect disease markers in breath May 19th, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Plasmon-powered upconversion nanocrystals for enhanced bioimaging and polarized emission: Plasmonic gold nanorods brighten lanthanide-doped upconversion superdots for improved multiphoton bioimaging contrast and enable polarization-selective nonlinear emissions for novel nanoscal May 19th, 2017

Announcements

GLOBALFOUNDRIES and Chengdu Partner to Expand FD-SOI Ecosystem in China: More than $100M investment to establish a center of excellence for FDXTM FD-SOI design May 23rd, 2017

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Leti Will Demo World’s-first WVGA 10-µm Pitch GaN Microdisplays for Augmented Reality Video at Display Week in Los Angles: Invited Paper also Will Present Leti’s Success with New Augmented Reality Technology That Reduces Pixel Pitch to Less than 5 Microns May 22nd, 2017

Graphene-nanotube hybrid boosts lithium metal batteries: Rice University prototypes store 3 times the energy of lithium-ion batteries May 19th, 2017

Environment

Can crab shells provide a 'green' solution to malaria? Study shows how a mixture of chitin and silver nanoparticles inhibits growth of mosquito larvae May 12th, 2017

NanoMONITOR shares its latest developments concerning the NanoMONITOR Software and the Monitoring stations April 21st, 2017

Wood filter removes toxic dye from water April 21st, 2017

Making Batteries From Waste Glass Bottles: UCR researchers are turning glass bottles into high performance lithium-ion batteries for electric vehicles and personal electronics April 19th, 2017

Fuel Cells

Stanford scientists use nanotechnology to boost the performance of key industrial catalyst May 18th, 2017

MIT Energy Initiative awards 10 seed fund grants for early-stage energy research May 4th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Scientists boost catalytic activity for key chemical reaction in fuel cells: New platinum-based catalysts with tensile surface strain could improve fuel cell efficiency December 19th, 2016

Nanobiotechnology

Zap! Graphene is bad news for bacteria: Rice, Ben-Gurion universities show laser-induced graphene kills bacteria, resists biofouling May 22nd, 2017

Sensors detect disease markers in breath May 19th, 2017

Oddball enzyme provides easy path to synthetic biomaterials May 17th, 2017

The brighter side of twisted polymers: Conjugated polymers designed with a twist produce tiny, brightly fluorescent particles with broad applications May 16th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project