Chopping and changing

Scientists at Queen’s University Belfast have discovered a new eco-friendly way of dissolving wood that may help its transformation into products such as biofuels, textiles, clothes and paper.


Dr Héctor Rodríguez and Prof Robin Rogers from the university’s School of Chemistry and Chemical Engineering worked with researchers at the University of Alabama, Tuscaloosa, to come up with a more cost and energy-efficient way of processing wood.


At present, wood is mainly broken down by the Kraft pulping process, which originated in the 19th century and uses a wasteful technology that relies on polluting chemicals.


The key reason for using this method is that, until now, it has been very difficult to break down and separate the different elements of wood any other way, and any alternatives to the process have presented similar problems.


The researchers found that chips of both softwood and hardwood dissolved completely in ionic liquid and only mild conditions of temperature and pressure were needed. By controlled addition of water and a water-acetone mixture, the dissolved wood was partially separated into a cellulose-rich material and pure lignin.


The process is much more environmentally friendly than the current method as it uses less heat and pressure and produces very low toxicity while remaining biodegradable.


Dr Héctor Rodríguez said: ‘The discovery is a significant step towards the development of the biorefinery concept, where biomass is transformed to produce a wide variety of chemicals. Eventually, this may open a door to a truly sustainable chemical industry based on bio-renewable resources.’


Approaches that the scientists are considering for the future include the addition of eco-friendly additives to the ionic liquid system or the use of catalysts.


The researchers are hoping to eventually achieve better dissolution under even softer conditions and are also trying to achieve complete separation of the different elements in one single step.


Both teams are also focusing on biomasses, which are rich in essential oils and can later be used in processes such as the manufacture of fragrances.