Scientists Identify Cheaper, Greener Catalyst for Biofuels Processing

Fuels that are made from non-petroleum-based biological sources could soon become greener and more affordable, as a result of the research performed at the University of Illinois’ Prairie Research Institute that analyzes the use of a processing catalyst created from palladium metal and bacteria.

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Biofuels are produced from renewable materials such as algae or plants, and provide an alternative to petroleum-based sources. However, a number of biofuels are expensive to manufacture as the precursor product, bio-oil, has to be processed before it is conveyed to the refinery to be converted into liquid fuel. Illinois Sustainability Technology Center researcher B.K. Sharma and his co-authors have identified and examined a new processing technique.

Bio-oil forms from the same chemical reaction that forms petroleum. But what takes millions of years naturally in the ground takes only minutes in the lab using a process that is very similar to pressure cooking.

Sharma

Their findings, published in the journal Fuel, specify a cheaper, more environmentally friendly and renewable catalyst for processing employs uses regular bacteria and the metal palladium, which can be recovered from waste sources such as catalytic converters, street sweeper dust, discarded electronics, and processed sewage.

The bio-oil created in the lab from algae contains impurities like oxygen and nitrogen, but treating it with palladium as a catalyst during processing helps eliminate those impurities to meet clean-air requirements, Sharma said.

For the palladium to work well, the bio-oil must flow past it during processing. Earlier studies have revealed that allowing the oil flow through porous carbon particles infused with palladium is an effective technique, however those carbon particles are not economical, Sharma said.

Instead of using commercially produced carbon particles, we can use bacteria cell masses as a sort of biologic scaffolding for the palladium to hold on to. The oil can flow through the palladium-decorated bacteria masses as it does through the carbon particles.

Sharma

To examine the effectiveness of the new method, Sharma and his co-authors performed a range of physical and chemical analyses to establish if their new processing treatment created a liquid fuel that matches in quality to one created using the commercially produced catalyst.

We found our product to be as good or even slightly better. We were able to remove the oxygen and nitrogen impurities at a comparable rate, and yielded the same volume of product using our cheaper, greener catalyst as is observed using the more expensive commercial catalyst.

Sharma

The more expensive commercial catalyst has the added advantage that it can be used over and over without prolonged processing, while the Sharma group’s palladium-on-bacteria catalyst will need to endure processing to be reused.

It is a minor caveat. The fact that we have shown the potential of making refinery-ready crude oil from algae bio-oil using a catalyst that can be prepared from low-grade recycled metals and green and economical bacterial biomass proves that this is a very promising advancement. In addition, this bio-catalyst would work equally well in petrochemical processing.

Sharma

The research was conducted in partnership with professors Joe Wood and Lynne Macaskie from the University of Birmingham, funded through the Birmingham-Illinois Partnership for Discovery, Engagement and Education program. The research was also supported by the Natural Environment Research Council, UK.