Wageningen chemists and chemical technologists are collaborating to develop new catalysts to transform bio-resources into materials with greater efficiency. ‘As a society, we seek simple solutions to a very complex problem.’
The global economy is, in large part, based upon fuels and raw materials that are not sustainable. Natural gas, oil and coal: it takes increasing efforts to extract these resources from the earth’s crust, and the production and use of these materials are often bad for the environment. The solution may well lie in a shift towards an economy based on renewable resources. This includes biobased materials such as corn residues, algae, sugar cane residues or manure, all of which can serve to generate heat, electricity, fuels, chemicals and materials.
‘Biobased alternatives can be created for almost any chemical or material’, says Harry Bitter, professor of Biobased Chemistry & Technology at Wageningen University & Research. ‘But, this does require the necessary chemistry and technology. You cannot simply turn corn residue into high-value plastic suited for all sorts of specialised applications.’
If you wish to produce a high-value end product, the raw materials must first be refined and processed, much the same as we would typically do in the oil industry. This process is known as biorefinery. Biorefinery creates the building blocks that can then be transformed into larger units. These bio-building blocks are used in the chemical industry. ‘We are working on novel methods to optimise this transformation process’, says Bitter. ‘We work at a molecular level in order to ultimately change the economy on a global scale.’
Molecules from bio-resources
The challenge lies in the fact that these biobased resources, also known as biobased feedstock, have a different chemical composition than oil-based feedstocks. Thus, transforming a bio-resource into a usable product generally requires more steps than would be the case using oil-based feedstock. For example, a plastic bag made of polyethene is made from sugar: first, the sugar must be transformed into ethanol, and then into ethylene. Only then can the existing process be applied to make it into a plastic bag. ‘This is a more extensive, and thus more costly, process than the oil-based processes’, Bitter explains. ‘If we want this to compete with fossil feedstocks, the processes must be optimised further, or new processes must be developed. That is what we are working on.’
Designing and testing
The Wageningen scientists focus on designing new catalysts. Catalysts are materials that cause or accelerate chemical reactions without being used in the reaction. Catalysts can help to lower the temperature needed for a particular chemical reaction. A catalyst, as used in car exhausts, transforms hazardous materials into materials with less dangerous properties.
‘The currently available catalysts are, unfortunately, mostly designed for fossil-based resources, not for biobased materials’, Bitter explains. ‘This is why we are working on new catalysts. We design and fabricate them in our lab, after which we test them to see what effects they have. This is done in various ways: based on calculations and known properties, but also through trial and error. Depending on the results, we tweak the design. Thus, we ultimately make better and better catalysts.’
Sustainable at many levels
For a truly sustainable economy, merely using sustainable resources is not enough. The processes themselves must also be sustainable. Here, there is still room for improvement, says Bitter. ‘Although catalysts lower the amount of energy needed to cause chemical reactions, energy is still required’, he states. ‘In the petrochemical industry, this energy is traditionally supplied by heat from fossil fuels. Not very sustainable. But, catalysts can also operate on sustainably produced electricity or light. This provides an extra edge in designing new catalysts.’
Besides, the researchers want the catalysts themselves to be as sustainable as possible, for example, by making them from readily available materials. Bitter: ‘As few precious metals as possible.’
Over the past years, chemists and chemical technologists have made much progress in developing high-value biobased solutions for industries. But, says Bitter, there is still a long way to go. Sometimes he senses pressure to get it done faster. ‘But, you must realise that the oil industry spent 150 years to optimise its processing methods, and is, even now, still in development. As a society, we would prefer to switch to a biobased economy within a decade. That is not realistic. We are seeking simple solutions for a very complex problem.’