Abstract:
Almost all soaps and detergents used daily rely on chemicals derived from non-renewable feedstocks. As demand for these finite resources continues to grow, developing renewable alternatives to fossil-derived chemicals is becoming increasingly important. Lignin, a complex polymer making up around 25% of wood, represents one promising yet largely underused source of renewable carbon. Unlike cellulose and hemicellulose, which are extracted from biomass for paper production, lignin is often burned for low-value energy because its complex and sensitive chemical structure makes it challenging to transform into useful chemicals and materials. This raises an important question: can lignin be extracted and modified to create sustainable alternatives to conventional detergents?
To investigate this, the goal of this project was to protect lignin using aldehydes and extract it from wood in a way that preserves its chemical structure, before chemically modifying it through reactions with amines. The resulting products were characterised using NMR spectroscopy and evaluated to determine their physical and chemical properties.
Lignin was successfully reacted with amines, demonstrating that its structure can be modified to introduce new functionality. However, the resulting material showed limited water solubility, reducing its suitability as a conventional soap or detergent ingredient. On the other hand, this property suggested an alternative application in water treatment. The modified lignin has potential as a flocculant, a material that gathers small suspended particles into larger aggregates that can be more easily separated from water.
Poster: