Researchers in Belgium have found a more eco-friendly way to turn waste from the paper industry into useful chemicals.

Scientists around the world have long been examining ways to convert lignin, a naturally occurring by-product from pulped wood, into valuable chemical building blocks.

“The traditional method to remove lignin from the pulp requires heavy chemistry and has side-effects: you end up with lignin that is unsuitable for further processing,” explained Professor Bert Sels from the KU Leuven Centre for Surface Chemistry and Catalysis.

As a result, this lignin is usually burned — even though it is a rather low-grade fuel.

Instead of working on making best use of this side stream of degraded lignin, the researchers at KU Leuven developed an alternative method that simultaneously converts wood into usable paper pulp and high-grade lignin-derived products.

“Our method involves feeding wood into a small chemical reactor and adding a catalyst — to set off the chemical reaction — as well as a solvent,” said Professor Sels. “With the right temperature and pressure, we can separate the lignin from the pulp and disassemble it into smaller components. The result is a lignin oil that is easier to convert into chemical building blocks. These building blocks, in turn, can be used in plastic, insulation foam, solvents, colorings and flavorings, medicines, ink, paint, and so on.”

This study takes a new approach to the concept of bio-refining, according to Professor Sels: “For the first time we focus on lignin — and not cellulose — as the starting point to make chemical building blocks from wood.”

The findings of the research have been published in the journal Energy & Environmental Science.