Research

A revolution in waste water treatment

Published 5 October 2012

It's been called the "miracle material" of the 21st century and articles wax lyrical about its ability to transform fields like electronics, but could graphene also revolutionise waste water treatment?

Graphene, said to be the strongest material ever measured, comprises a sheet of carbon atoms just one atom thick giving a very high theoretical surface area – three million stacked sheets of graphene would be just 1mm thick.

In an article in the current edition of Water & Sewerage Journal, Steven Ragan of Jacobi Carbons Limited and Dr Raymond Whitby and Professor Andrew Cundy of the University of Brighton's Nanoscience and Nanotechnology Group compare developments in "old" and "new" carbons for waste water treatment.

These authors note that despite its tiny size, a review of recent literature shows graphene could be effective in waste water treatment. As graphene oxide, it can be incorporated into composites and therefore could become an advanced "super sand" filter they say. This is because graphene oxide can be induced to form a coating around sand grains while adding aromatic thiol molecules to the graphene increases its ability to remove some of the newer industrial contaminants found in waste water.

They add that it could also improve the efficiency of catalytic and photocatalytic treatment processes by modifying the electronic properties of titanium dioxide nanoparticles.

In addition to reviewing research on the newest carbon treatments of waste water, the article 'Old and new carbons for wastewater treatment' looks at "old" or activated carbons. It said advances in the production of activated carbons are also meeting the challenges from new forms of contamination thrown up by modern industrial processes, including highly polar contaminants such as metaldehyde.

They said: "'old' carbons, such as activated carbon, continue to rise to the challenge of new water and wastewater applications such as bromate removal. 'New' carbons, such as graphene, continue to emerge from fundamental sciences challenging both scientists and water treatment engineers to apply their unique properties to novel water and wastewater treatment processes."

They add that understanding the mechanisms of reactions at the nanoscale with "simpler" models of carbon such as graphene will also reinforce the development of macro-scale carbons. The aim is to bring down the cost of production and translate graphene into the market place.

Dr Steven Ragan and Dr Raymond Whitby are members of the British Carbon Group, a special-interest group of the Royal Society of Chemistry, Institute of Physics, and Society of Chemical Industry which represents the carbon research community primarily in the UK and overseas.