Renewables and Green Chemistry

Green Chemistry is rapidly gaining prominence in many countries with the emergence of awards, undergraduate degree programs, and major research funding initiatives, with spectacular achievements in the field on a regular basis. Much of the earlier research focused on the general areas of waste minimisation in chemical synthesis, especially in using alternative reaction media such as ionic liquids and supercritical carbon dioxide, solventless reactions, catalysis, oxidation reactions, alternative energy sources and energy usage, toxicity, and atom efficiency, and other issues associated with minimising waste.

Given the increase in greenhouse gas emissions due to the use of petroleum (and other fossil fuels) and the impending limits of this non-renewable resource as evidenced by petrol price increases, there is a need to develop renewable resources such as biomass as the feedstock for the chemical industry and as an energy source. This includes biomass that is traditionally discarded as waste (see below). The advantages of deriving our chemical, and energy needs, from renewable sources including biomass are obvious and crucial to our way of life. The switch to the use of biomass as a feedstock and an energy source is an important global initiative in getting the world onto a sustainable trajectory.¹

Technology roadmaps for the comprehensive use of biomass will play an important role in identifying key areas of research and development. Systematic consideration of biomass properties and best available technologies is required together with addressing triple bottom line issues. Chemicals derived from biomass will be a ‘supply chain’ for the chemical industry for transformation into a plethora of compounds. Clearly these will need to be based on green chemistry, taking advantage of the aforementioned early focus in the field as discussed above, and ongoing developments.

The above so called waste should be considered a valuable resource for new technologies. In fact, all forms of biomass, including the residue from the chemical processing of biomass, are a potential renewable source. In this context, the Western Australian State Government has a policy of zero landfill waste by 2020.² While this is unlikely to be achieved it nevertheless gives a clear message and challenge from Government that scientists and engineering need to be engaged in solving the problem. It is a major challenge for consideration—‘Landfill’ opportunities for green chemistry!

The shift to renewable feedstocks based on biomass is a formidable challenge, and much needs to be done. Research centres dedicated to this are appearing on a regular basis.³ Despite this the use of biomass in green chemistry initiatives has received little attention in Green Chemistry, with a limited number of articles dedicated to the field since the journal was founded in 1999. Articles on renewable feedstocks, and energy, are welcomed. They can be in the general areas of deriving chemicals from waste from aquaculture, fisheries, agricultural and plantation forestry, and the biomass from crops grown exclusively as a source of biomass, as in the palm oil industry in Malaysia,⁴ extraction and conversion of high value added compounds, biofuels, gasification, biopolymers, carbon for mineral processing, and more.

Other challenges/areas in biomass utilisation include: (a) Bio-catalysis as a route to commodity chemicals, using microbes and enzymes. (b) Separation of cellulose, hemicellulose, and lignin, alternative energy sources and new separation technology. (c) Biodegradable polymers using carbohydrate feedstocks. (d) Liquid and gaseous fuels and lubricants, chiral feedstocks for drug syntheses, etc. (e) Mineral processing—alternative energy sources and reductants, bio-flotation, and smelting. (f) Gasification and pyrolysis as a route to liquid fuels, feedstock for the chemical industry, hydrogen for the ‘hydrogen economy’, and carbon material. In addition, economic and management issues, including developing low cost processes with a small footprint, for use in rural areas, transport of biomass, compactions, life cycle assessment, etc. need to be addressed, along with social issues including community awareness and impacts on the rural community and ecosystem functions.

 

Professor Colin Raston

Editorial Board Chair, Green Chemistry

University of Western Australia

References

1. P. Anastas, Meeting the challenges of sustainability, Green Chem., 2003, 5, G29.
2. The Western Australian State Sustainability Strategy, 2003, Government of Western Australia, Quality Press, ISBN 0 737 0212 X.
3. (a) http://www.bc.bangor.ac.uk/; (b) http://web.utk.edu/%7Etfpc/; (c) http://www.nesungrant.cornell.edu/; (d) http://www.wwrrec.cf.ac.uk/about/objectives.asp.
4. Malaysian Palm Oil Promotion Council, http://www.mpopc.org.my.

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