(From left) Tnah, Prof Wu and Yong’s research has shown that lignocellulosic biomass could be a perfect sustainable alternative to make green products.
CUTTING down on fossil fuels is a major component of efforts to mitigate the impact of climate change and contribute to the shift towards more sustainable forms of energy production and consumption.
Lignocellulosic biomass is an excellent sustainable alternative that can be used to make green products.
Lignin, being one of the major components in lignocellulosic biomass, is the second most abundant natural polymer on earth, although it is currently used sparingly. Lignin waste is typically burned to produce energy.
In 2017, 70 million tonnes of lignin waste was produced. However, only 1% to 2% of lignin was used to make non-fuel products such as fertilisers and adhesives. This means that we’re not fully utilising lignin’s potential, which makes it harder for companies to produce sustainable products via biorefinery.
In plants, lignin acts as a protective barrier which helps make plants stronger and keeps them safe from biological or chemical damage.
However, lignin is difficult to be converted into other products because it is strong and does not break down easily. Moreover, lignin depolymerisation processes that exist today are expensive and use harsh chemicals.
This makes it hard for companies to make sustainable products from lignin, at a low cost, with green approaches.
Recently, researchers have looked into the use of ionic liquids and deep eutectic solvents (DESs) to make it easier to turn lignin into valuable products.
While most ionic liquids are expensive and possess potential hazards, DESs are better alternatives because they are more environmentally friendly and less costly. DESs have also been used in biomass pretreatment and transformation to make various bio-based products such as furfural.
“Researchers found that combining water and DES could make converting lignin into other products easier,” says Monash University Malaysia’s School of Engineering associate head of school for graduate research Associate Professor Wu Ta Yeong.
“This research adds an alkaline solution to lignin to make it into aromatic monomers. Using DESs could make it easier and less expensive for companies to produce sustainable products at one atmospheric pressure.”
Prof Wu and his team, which consists of his former PhD student Dr Victor Ong Zhenquan and current PhD students Yong Khai Jie and Tnah Shen Khang, tested a method using sodium hydroxide (NaOH) solution with aqueous DES in biomass pretreatment and transformation.
They tried different NaOH concentrations, temperatures and time periods to see what worked best for such a process.
They also added different metal chloride catalysts to see if they could improve the depolymerisation process. The goal was to find a way to break down and transform lignin from biomass more efficiently at one atmospheric pressure.
Their research concluded that using NaOH-aqueous DES as a depolymerisation medium could be promising for promoting milder and inherently safer lignin depolymerisation at one atmospheric pressure.
The addition of metal chloride catalysts also improved the process by increasing aromatic monomer yields, while reducing reaction temperatures.
Furthermore, physical and chemical characterisation studies were performed to provide further evidence supporting this proposed approach.
Monash University has risen 13 places in the Times Higher Education World University Rankings 2023, to rank 44th globally. The institution’s success is a result of its strong industry and government collaborations, which provide excellent opportunities for research and professional development.
Monash University will be organising a Virtual Postgraduate Day on April 15, from 2pm to 4pm at https://monashmalaysia.info/3loSId2
