Ionic liquids remove toxic mercury from natural gas

Ionic liquids are able to dissolve almost anything and possess special properties which mean they always remain liquid and never evaporate. Despite being known for more than a century, the potential to use the liquids for environmental clean-up efforts is only now being realised.

Fossil fuels such as coal and gas emit mercury - a substance which poses significant health and safety risks to the environment, food chain and industrial plants but is also difficult and expensive to remove. Academics at Queen’s University Ionic Liquid Laboratories (QUILL) in Belfast, UK, in partnership with Malaysian oil and gas giant Petronas, have used the super-solvent properties of ionic liquids to develop technology which removes mercury from natural gas.

The process is said to be up to six times more efficient and effective than some current methods. The chief executive of the Institution of Chemical Engineers (IChemE), David Brown, said it has “the potential to make industrial plants safer and reduce the devastating impact of mercury on the environment and health”.

The technology was this month recognised by IChemE, when QUILL and Petronas received three awards - including the overall prize - at the IChemE Awards 2013. The development is “already making a major contribution to mercury removal”, said Brown, who added, “In a remarkably short time, the technology has been developed and installed in two commercial units - the first time ionic liquids have been used commercially in the energy sector.”

He explained that ionic liquids can dissolve “an astonishingly wide range of things, such as sulfur and phosphorus, which currently require more harmful solvents. They even have the ability to remove bacteria like MRSA from surfaces.

“lonic liquids have been hailed as one of the innovations of the 21st century, but it is only now that their potential is being exploited,” said Brown.