/ 31 May 2013

Conversion of metals to reduce harmful chemicals

Professors Cobus Kriek of North-West University and Vijay Ramani of the Illinois Institute of Technology in Chicago at the metal vapour deposition equipment.
Professors Cobus Kriek of North-West University and Vijay Ramani of the Illinois Institute of Technology in Chicago at the metal vapour deposition equipment.

 

Approximately R4-million of unique metal vapour deposition equipment has been installed in the Chemical Resource Beneficiation (CRB) research focus area at the Potchefstroom campus of North-West University.

Dr Cobus Kriek of the CRB research focus area says that the equipment will primarily be applied to develop catalysts to convert harmful industrial gaseous emissions to useful chemical components.

Another priority of this equipment will be to reduce the noble metal content of these catalysts to make the electrochemical technology more economically viable, and ensure a constant and sustainable off-take of noble metals. These metals are still the most effective and will not be easily replaced by non-noble metal catalysts.

An example of this is the use of platinum in fuel cells. Kriek says that noble metals are primarily used in catalysts for electrochemical processes because it speeds up the electron transfer process without the catalyst getting consumed. However, they are a scarce and finite resource and are expensive to employ as an environmental remediation processes.

Using noble metals for useful chemicals
The ultimate goal is to find catalysts that can convert harmful gaseous emissions, such as sulphur dioxide and carbon dioxide, to useful chemical components.

Kriek says that these conversion processes are known to work, but the right catalyst still needs to be found to make these processes economically viable. According to Kriek, these catalysts have a limited lifespan and therefore the CRB research also focuses on the recovery of these metals from spent catalyst materials.

The processing of catalysts
The metal vapour deposition equipment is one of a kind in South Africa, according to Kriek, and only a limited number of universities in first world countries have access to such equipment.

It is used to sputter, through metal vapour deposition, up to four different metals sequentially or simultaneously onto a 4mm x 4mm target. This is repeated for different ratios of the co-sputtered metals onto a total of 64 individual targets to create 64 different catalysts.

These catalysts can then be tested simultaneously, under the same conditions, for their catalytic activity for a specific reaction to identify the most reactive metal composition.

"This equipment will therefore reduce the development process dramatically," said Kriek.

Continuing research and investment
Kriek submitted a research proposal to Anglo Platinum in 2009, which set the ball rolling for this project. There are three investors in the research programme: Anglo Platinum, North-West University and the department of science and technology through the HySA (Hydrogen South Africa) Infrastructure Centre of Competence located at North-West University's Potchefstroom campus.

Kriek says that they are also working with researchers from universities abroad and Professor Vijay Ramani of the Illinois Institute of Technology in Chicago, who is an extra-ordinary professor on this subject at North-West University.

A technical advisory committee has been established with Kriek (North-West University), Ramani (Illinois Institute of Technology), Professor Paul McGinn (University of Notre Dame), Dr Neville Plint (Anglo Platinum), Dr Dave Thompsett (Johnson Matthey), and Dr Dmitri Bessarabov (HySA Infrastructure Centre of Competence).

Some of the equipment has already been commissioned and the aim is to have the laboratory fully operational. Several post-graduate students as well as post-doctoral research fellows will participate in this programme.

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