How do we best utilize the diverse structures of cellulose most efficiently and sustainably? Yanrong Liu’s work on predictive screening of ionic liquids for dissolving cellulose and experimental verification is aiming for a way to recycle potential ionic liquids from cellulose-ionic liquid mixtures.
On the cover of Green Chemistry volume 18 from last year, little cartoon creatures are walking down the page, representing ionic liquids where anions are red and cations are blue. This cover article is written by Yanrong Liu, PhD at the BIOENG research centre at DTU Chemical Engineering, and sums up the work from her PhD project: ‘Research of conductive spinning solution in ionic liquid and enzymatic modification cellulose system’.
On an industrial scale, cellulose, the most abundant organic polymer on Earth, is used for such diverse purposes as cotton textiles, paper products, consumables, biofuel, building materials and in laboratories as a stationary phase for thin layer chromatography. However, the efficient utilization of cellulose is very challenging.
The objective of Yanrong’s PhD project is twofold: Firstly, to establish a cellulose model and screen potential ionic liquids for dissolving the cellulose with the software tool COSMO-RS and verify the prediction result by experiment. Secondly, to develop a new method for recycling ionic liquids from water-ionic liquid mixtures after the conductive fibre spinning.
Especially the second step has “green potential”, and this is one of the reasons that an article by Yanrong ended up on the cover of Green Chemistry last year. And with the effectiveness of green production follows economic advantages:
“Being economically minded is the key factor for the application of ionic liquids in the cellulose fibre industry. Therefore, it is urgent and necessary to develop good methods for ionic liquid recycling,” Yanrong explains.
The purpose of dissolving cellulose is to be able to create new materials such as conductive fibres which may replace metal wires for conducting electricity.
Cables and conductive fibres
Yanrong’s PhD project is set to be finished by the end of this year. So far, the study has shown that the software tool COSMO-RS is a rapid and a priori thermodynamic tool for predicting the solubility of cellulose in ionic liquids. It was also found that the strength of hydrogen bonds between cellulose and ionic liquids is a key factor for dissolving cellulose.
There are many applications for the COSMO-RS tool. The overall goal in Yanrong’s PhD project is to use it to screen better ionic liquids for dissolving cellulose to make new materials such as conductive fibres that may replace metal wires for conducting electricity.
“Metal is the most frequently used material in cables. But with the right methods, supported by COSMO-RS, we can use conductive fibres instead which is light weight, cheap and safe. Other uses for the conductive fibres created from cellulose might be bioactive probes and capacitive energy storage,” Yanrong Liu says.
Read Yanrong Liu's research article 'Research of condcutive spinning solution in ionic liquid and enzymatic modification cellulose system' here.