Making paint from pine needles

Materials World magazine
4 Jan 2019
christmas tree dump

Natural Christmas trees could provide more practical applications than pure decoration, by extracting the chemicals in their pine needles. 

Pine needles consist of up to 85% of the polymer lignocellulose – a chemical that makes the needles valuable but is too complex and expensive to exploit using conventional biomass processes. However, a University of Sheffield PhD study has been exploring methods of breaking down the lignocellulose into more useful base products, and the barriers preventing industrial deployment. 

PhD student Cynthia Kartey, who is leading the study, said, ‘My research has been focused on the breakdown of this complex structure into simple, high-valued industrial chemical feedstocks, such as sugars and phenolics, which are used in products like household cleaners and mouthwash.’ 

Kartey believes her process is simple and economical enough for biorefineries to adopt. It involves using solvents and heat to reduce the needles into a bio-oil liquid, containing glucose, acetic acid and phenol – feedstocks for making adhesives or vinegar. The bio-char byproduct can be used in other industries, so there would be zero waste. 

The method is considered as sustainable not only due to being waste-free, but as it also creates a new supply chain for essential chemicals that would otherwise need to be sourced from less-sustainable operations.   

The university’s Department of Chemical and Biological Engineering Senior Lecturer Dr James McGregor said, ‘The use of biomass to produce fuels and chemicals currently manufactured from fossil resources will play a key role in the future global economy […] If we can utilise materials that would otherwise go to waste in such processes, thereby recycling them, then there are further benefits.’ 

McGregor added that the team is currently analysing the processing of other organic waste products, including forestry, spent grain from breweries and foods. 

Each year, around 7 million Christmas trees go to landfill in the UK, and the vast quantity of pine needles they shed take years to degrade, releasing huge amounts of carbon into the environment. And while a re-purposing service is unlikely to be available in time for next year, rolling out such a scheme would reduce these emissions, lowering the carbon footprint of Christmas trees, and offer a practical product to boot.