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A new powerful and low-cost technique has been devised for converting agricultural waste and used cooking oil into biodiesel, and even converting food waste and plastic to recycled products.

An international team of researchers, led by Australia's RMIT University, devised a new kind of an ultra-efficient catalyst that can extract low-carbon biodiesel, as well as other complex molecules, from a variety of impure raw materials.

This new catalyst is so reliable that it can draw biodiesel from low-grade sources such as feedstock, over half of which is nothing more than contaminants. Its efficiency can double the productivity of existing manufacturing processes that take old tires, microplastics, and even food scraps. These scraps are then turned into valuable chemical precursors used in various products such as packaging, fertilizers, and even medicines.

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The design of the catalyst, as well as the conversion process, is detailed in the journal Nature Catalysis.

 

A Microscopic Sponge

To create the ultra-efficient catalyst, researchers fabricated a ceramic sponge on the micron scale. The catalyst, more than 100 times thinner than a single strand of human hair, is also highly porous and is embedded with different active components.

During operation, molecules from the raw materials enter the sponge through the first layer - with larger pores - and undergo a chemical reaction. The products of this first layer then enter smaller pores and are subjected to the second chemical reaction. This marks the first multi-functional catalyst that introduces a series of chemical reactions, in sequence, inside a single particle, promising change in the $34 billion global market for waste catalysts.

"Catalysts have previously been developed that can perform multiple simultaneous reactions, but these approaches offer little control over the chemistry and tend to be inefficient and unpredictable," said Professor Karen Wilson, co-lead in the study from RMIT University. She added that their approach was "bio-inspired," looking into nature's own catalysts, allowing the microscopic sponge to conduct several chemical reactions "in a set sequence."

"It's like having a nanoscale production line for chemical reactions-all housed in one, tiny and super-efficient catalyst particle," Wilson added.

Devising A Cheaper Way for Biodiesel Production

Researchers noted that the ultra-efficient catalyst is cheap to manufacture and requires no precious metals that drive its cost. Furthermore, creating low-carbon biodiesel from agricultural waste through the catalyst "requires little more than a large container, some gentle heating and stirring," according to a press release from RMIT.

"This is particularly important in developing countries where diesel is the primary fuel for powering household electricity generators," Wilson noted. The catalyst, promising a low-technology and low-cost method, could boost biofuel production and reduce reliance on conventional diesel sourced from fossil fuel. Wilson further added that their new technology could help solve long standing problems of energy sufficiency and cutting carbon emissions by encouraging farmers to produce their own biodiesel from their own generated agricultural wastes - rice bran, castor seed and cashew nut shells.

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The research team at the RMIT School of Science is now looking to scale up the production of the catalyst material, moving from grams to kilograms. They are also planning to incorporate 3D printing technologies and speed up its commercialization.

"We're also hoping to expand the range of chemical reactions to include light and electrical activation for cutting-edge technologies like artificial photosynthesis and fuel cells," explained Adam Lee, co-lead investigator also from RMIT.

Check out more news and information about biofuels in Science Times.