The global chemistry industry is looking to nature to redefine the way it operates, with a view to becoming a 21st-century model for sustainability.
It is not unusual for the word 'chemicals' to elicit shudders, so automatically is it associated with environmental contamination, hazard and risk to the biosphere. Such perspectives generally fail to notice that chocolate, flowers, iPhones and even people are made up of chemicals – as is everything that has mass.
Monash University's Professor Milton Hearn says the problem is that, since their modern inception about 200 years ago, chemical sciences and industries have considered chemicals, as well as their production and disposal, in a potent but ultimately narrow way.
At the core of this conventional approach to manufacturing is what developmental psychologists call 'formal operative' logic – a way of thinking that results in linear cause-and-effect production systems. In industry, this validates a mindset that regards waste as one of those effects, with consequences that are rarely questioned at the product design stage. Nature, however, shows there is an alternative paradigm.
As Professor Hearn enjoys pointing out, cause-and-effect chemical reactions occur constantly in nature. But in nature they exist within broader interactions that deactivate toxins, re-use wastes and recycle by-products.
The outcome, in nature, is a fascinating efficiency that is starting to inspire a new vision for the chemical sciences and industries, from pharmaceuticals and petrochemicals through to household products such as detergents. This comparatively new endeavour has been dubbed 'green chemistry' because of its tendency to learn from, mimic or borrow from nature.
As the director of the Centre for Green Chemistry at Monash, Professor Hearn has been testing just how far it is possible to take chemistry beyond its traditional path.
"Green chemistry has allowed people to query the design rules, the technical strategies and the methods that can be brought to bear on the problem of making the best use of the planet's chemical resources," he says. "The resulting solutions are so exciting that I have wondered why they were not discovered decades ago."
Professor Hearn thinks there is a real opportunity to move to more cost-effective chemical manufacturing processes that embody a more enlightened and sustainable way of making and using chemicals.
Or to get to the heart of the matter: "If we stay with the old ways, then this will not be a happy planet to live on."
For the Monash Centre for Green Chemistry this is not just idle chatter. Professor Hearn's team has achieved scientific milestones significant enough to attract several industry partners.
Progress has been further bolstered by the Australian Government, which has provided funds for a new state-of-the-art building to house Green Chemical Futures. This initiative will double as the hub of the Global Institute of Molecular Sustainability and the Victorian Centre for Sustainable Chemical Manufacturing, which function as global and local networks of green chemistry professionals, their research and training activities, and industry partners.
In discovering more benign ways to make the enormous range of chemicals required by advanced economies, green chemistry results in a surprising balance sheet. Typically higher yields and purer products are being achieved using less energy and generating less waste and contamination.
In fact, the discipline has developed a specific framework of measurements for understanding resource use and waste generation. One such measure, called the E-factor, allows green chemists to model all the inputs and by-products associated with a chemical production process. The E-factor was one of the first and simplest tools to come out of green chemistry a decade ago.
The pharmaceutical industry is one area where the E-factor is having an impact. Pharmaceuticals typically have E-factors of between 100 and 150,000. At worst, this means 150,000 kilograms of chemicals are used for every kilogram of active drug made, Professor Hearn says.
"The clever chemical science and engineering is to bring the E-factors down as close to one as possible – that means, you don't generate any waste. This is a key consideration for industry. Waste is the reason why industry has compliance requirements, waste disposal costs and production inefficiencies. So low E-factors deliver huge cost savings."
This has the effect, Professor Hearn says, of allowing scientists to home in on more benign ways to manufacture chemicals. While this can take many forms, one example is green chemistry's makeover of catalysts. These are the molecules that drive chemical reactions that otherwise would not readily occur, and remain unchanged themselves during the reaction.
In biology, enzymes are examples of catalysts, and life as we know it is not possible without them. They assist everything from replicating DNA to digesting food. But in industry they are frequently toxic, hazardous to handle, expensive or made from low-abundance elements.
"Currently, about 60 per cent of all industrial chemical processes involve the use of corrosive strong acids or organic solvents to catalyse reactions," Professor Hearn says. "Historically, the production of nylon, for instance, required the use of oleum – an extraordinarily strong, corrosive and hazardous form of sulfuric acid."
Green chemistry has responded with the idea of the 'benign catalyst'. Sustainability gains are possible, for example, by converting the catalyst from a liquid form that is disposed, to a solid state that is fixed to a surface so it can be re-used hundreds or thousands of times. "That is one aspect we are working on – the whole-of-life recyclability of catalysts," Professor Hearn says.
Then there are projects to invent catalysts that are designed to result in harmless by-products such as the chemical H2O – water.
In one recent breakthrough, the Monash centre developed a benign catalyst to replace the use of strongly corrosive acids. The Monash alternative takes the form of a non-corrosive, re-usable, solid-state catalyst, which eliminates the need to neutralise and dispose of vast quantities of liquid acid.
Best of all, new benign catalysts have proved straightforward to apply at scale.
The same goes for by-products of chemical manufacture, substances such as carbon dioxide. Rather than release it into the atmosphere, green chemistry is making it possible to trap and convert carbon dioxide into other useful chemicals. The objective of green chemistry is to then apply the same design foresight to all production processes so by-products are returned to the chemical manufacturing supply chain.
This leads to the idea of 'industrial ecology' built on self-sustaining production processes. It replaces traditional chemicals manufacturing, where each production cycle starts with fresh feedstock. Surveys repeatedly find that this conventional, linear approach converts only 10 per cent of starting materials into usable products. The remainder becomes waste.
"Industrial ecology is an interesting concept," Professor Hearn says. "It views the supply chain as being made up of factories – not goods – so as to minimise the amount of material that ends up as waste.
"Industry tries to operate that way, but it hasn't yet reached the level of sophistication that we know is possible; to have everything that goes into the industry come out as a usable product, including by-products like carbon dioxide."
Green chemistry is both a principle and a functional approach that can change this, and it is winning industry support. This largely unnoticed industrial revolution is being driven by companies that are acutely aware that it is a step-change to capturing health, environmental and economic benefits.
"A lot of the vision of the early thought leaders – including at Monash – you now see embedded in corporate boardrooms, in government policy, in the way government agencies are starting to approach this whole issue of chemical sustainability in the broadest context," Professor Hearn says.
"It is a really exciting time because it is revitalising chemistry, its public interest and its relevance."
