Some background context
Increased level of pollution worldwide (soil, air and water) calls for urgent action and scalable solutions. Combined with increasing population growth to more than 9 billion people by 2050 (OECD 2012) the problem is far from being resolved. The 2018 Intergovernmental Panel on Climate Change (IPCC), a meta study co-written by more than 130 authors synthesizing over 6,000 scientific references reported that global warming caused by human activities (approximately 1°C of global warming since the Industrial Revolution) will likely reach 1.5°C between 2030 and 2050. They estimated that the world needs to spend US$ 2.4 trillion every year until 2035 to slow down the effects of climate change.
Green Chemistry Principles at Work
In 1998, Paul Anastas and John C. Warner published a set of principles to guide the practice of green chemistry (GC), formalizing a long tradition and informal GC. The Twelve Principles of Green Chemistry address a range of ways to reduce the environmental and health impacts of chemical production, and also indicate research priorities for the development of green chemistry technologies (https://www.greencentrecanada.com/green-chemistry/the-12-principles-of-green-chemistry/ ). They can be summarized as: 1) Waste Prevention, 2) Atom economy, 3) Less hazardous chemical synthesis, 4) Designing safer chemicals, 5) Safer solvents and auxiliaries, 6) Design for energy efficiency, 7) Use of renewable feedstocks, 8) Reduce derivatives, 9) Catalysis, 10) Design for degradation, 11) Real-time analysis for pollution prevention, and 12) Inherently safer chemistry for accident prevention (https://www.compoundchem.com/2015/09/24/green-chemistry/).
The practicality of the Principles has been very influential in production and innovation choices. Canadian scientists have been especially active in this field, with 700 publications in the last 2 years by the Centre in Green Chemistry and Catalysis (CGCC) members (https://ccvc.research.mcgill.ca/home.html). A prime example is catalysis, required in more than 90% of all industrial chemical processes, where CGCC is developing new tools for the preparation of molecules (e.g. solvent free green processes (solid state synthesis)) with specific functions and studying the environmental fate and biological effects of these reagents/catalysts that are introduced in the ecosystem. In addition, extensive research and implementation is performed for isolating or producing biomolecules and bioproducts from wood/plants and their derivatives (cellulose, lignin and sugars). Scientific publications are available through Green Chemistry, a peer-reviewed scientific journal (https://www.rsc.org/journals-books-databases/about-journals/green-chemistry/).
A Historical Case of Green Chemistry from Pulp & Paper
In late 70’s/early 80’s, dioxins and furans were found to be present in milk carton in toxic levels. This was a major crisis for the virgin bleached Kraft pulping process since the precursor’s molecules were getting more toxic when the pulp was bleached with elementary chlorine (Cl2, HOCl, NaOCl), e.g. tetrachloro dibenzofuran (TCDF) and tetrachloro dibenzodioxin (TCDD) and other isomers. Although there are 210 isomers of these chlorinated compounds, 2,3,7,8-TCDF and 2,3,7,8-TCDD showed the highest toxicity.
To better understand the issue, the scientists from FPInnovations (formerly PAPRICAN) developed the methods to analyze the concentration of these molecules in parts per quadrillion (ppq), allowing them to assess the safety of production processes. For example, the acceptable limit in bleach plant effluent in Quebec regulation was lower or equal to 15 pg/L (expressed as 2,3,7,8-TCDD toxic equivalents)! A few years later, what was called the « Dioxin Free Zone » was identified. This described the pulp bleaching conditions where the dioxin concentration (total TCDF + TCDD) was acceptable. It required to operate the bleach plant in the vicinity of a Kappa factor of 0.17 for softwood and/or at high chlorine dioxide (ClO2) substitution (e.g. +55%), to ensure that polychlorinated dioxins and furans are not formed. Consequently, the P&P industry had the solution to solve this issue by implementing this green chemistry approach. As of today, the large majority of virgin Kraft pulp is bleached with chlorine dioxide (i.e. 100% ClO2 substitution) as well as oxygen and hydrogen peroxide. Some are even totally chlorine free (TCF) bleaching processes. Moreover, in the paper recycling industry, many companies replaced the elementary chlorine bleaching (HOCl, NaOCl) by non-chlorinated agents (e.g. hydrogen peroxide, sodium hydrosulfite), reducing negative long-term impact on human health and on environment.
Going forward, how to apply the 12 Principles of Green Chemistry to the P&P industry, main-taining its core business and minimizing its environmental footprint? Here are a few frequently asked questions:
1) Is GC only from trees?
No, GC comes from any natural resources (animals, trees/plants, insects).
2) Is GC always green?
GC is a toolkit that reduces the environmental impact of the process to which it is applied.
3) Is GC requiring all 12 principles?
Best practices would be to consider as many as possible, so the final solution would have the best ROI in terms of sustainability.
4) Is one of the 12 principles more important than another?
It depends on the application. The goals will dictate which Principles are important.
5) Are catalysts green molecules?
The catalyst is a substance that isn’t consumed by the overall reaction; reduces energy use, increases yield and decreases by-products.
6) Are renewable natural molecules necessarily green?
Generally yes, as long as the overall process (availability, extraction, production) results in reduction of the environmental footprint. Regarding toxicity, what matters is concentration!
7) Is engineering part of GC?
The equivalent exists, Paul Anastas and Julie Zimmerman also developed the 12 Principles of Green Engineering ( https://www.greencentrecanada.com/green-chemistry/the-12-principles-of-green-engineering/ ).
8) How can we make sure we have a green chemical/product?
Preferably, raw material or feedstock should be renewable. Then, a detailed life cycle analysis (LCA) is necessary, however sometimes not possible because it requires a long and expensive process. Moreover, when developing a new chemistry and/or process, a detailed LCA is likely impossible because of too many unknown.
9) Can we make money with GC?
We know that GC can be financially viable, but it may take some time and the will from Industry and Consumers.
What’s next ?
Green Chemistry 12 Principles are highly useful and very actionable means to drive innovation strategies and accelerate the transformation our Industry.
As part of the decision process, it is our duty to put climate at the centre of our organization’s concerns. This is nothing less that investing in the sustainability of our enterprises, and that of Mankind. This is not a matter for tomorrow. Nor is it for Others. We can make a difference; Sustainable Innovation leads to Sustainable Prosperity.
* Image Source: ©2018 Royal Society of Chemistry, Anastas et al. (2018) Green Chemistry 20, 1929-1961.
The 2016 Canadian Green Chemistry and Engineering Award, sponsored by Green Centre Canada, was awarded to Dr. Roger Gaudreault for his significant contribution to Green Chemistry research and development through 30 years of dedicated work for the Pulp and Paper Industry, industrial water treatment and renewable energy.
Dr. Gaudreault's expertise notably spearheaded him to develop an integrated innovation Green Chemistry approach based on recycled fibres. His scientific and applied background helped developed strong partnerships between academia and industry. He has been a member of the Centre in Green Chemistry and Catalysis (CGCC) since 2011 and associate member of the Quebec Centre for Advanced Materials (QCAM) since 2018. Dr. Gaudreault's scientific interests include; green chemistry, neuroscience, kinetics of colloids, chemistry of pulping/bleaching and papermaking, recycling, corrosion inhibition, biomaterials and biofuels from wood biomass, and molecular modelling. Dr. Gaudreault did a Post-Doctoral Fellowship co-supervised by Professors David A. Weitz from Harvard University and Theo van de Ven from McGill University (2005-2006). He completed a PhD on molecular modelling from McGill University (2003); MSc. in Pulp and Paper from Université du Québec à Trois-Rivières (1991); and a BSc in Chemistry from Université du Québec à Chicoutimi (1986).
Dr. Gaudreault has also been named PAPTAC Fellow 2017 in recognition of his outstanding long-term and significant contribution to the Association, the pulp & paper and forest products industry and for the advancement of science and technology in the industry.