It isn’t often (like almost never) that a new technology with potential impact on the environment comes with its own natural solution. According to two papers published by scientists from Rice University (Texas, USA), this is the case with graphene oxide.
Graphene, a form of carbon, can be simply described as a form of graphite (as in pencil lead) that exists in sheets or layers one atom thick. It has an incredible number of potential applications. For example, it can be used in making plastics (polymers), ceramics, reinforced metals, electronics, drug-delivery devices, hydrogen storage, and with modification as a semiconductor. However, most of these applications require mass production to be significant.
One of the principle forms of graphene is graphene oxide, which is mostly carbon with oxygen and a few atoms of hydrogen. Graphene oxide is an insulator, meaning it doesn’t conduct electricity, but has many other properties that it shares with basic graphene. It is also potentially used as an intermediate form in the process of making graphene.
The long march from scientific discovery to a successful technology typically has a critical phase: Competitive mass production. It’s one thing to make something in a lab, or even produce a number of prototypes; it’s quite another to produce something in large numbers. It’s common for products and technologies to fail because they couldn’t be successfully mass produced – or even more commonly because they couldn’t be produced cheaply enough to compete with other similar or alternative products. So it’s important when a highly touted new technology, in this case the nanotechnology based on graphene, finds methods of mass production that have numerous advantages, including low cost.
The new process, described in the paper Improved Synthesis of Graphene Oxide published in the American Chemical Society (ACS) Nano, uses flakes of graphite, which is treated with potassium permanganate, sulfuric acid, and phosphoric acid. Though obviously very ‘active’ chemicals, they are inexpensive, well understood, and suited for mass production of graphene oxide. They also do not produce the kinds of explosive gas by-products common to other approaches.
In the opinion of James Tour, professor of chemistry at Rice and lead researcher for the graphene oxide production paper:
“Many companies have started to make graphene and graphene oxide, and I think they’re going to be very hard pressed to come up with a cheaper procedure that’s this efficient and as safe and environmentally friendly,”
The ‘environmentally friendly’ element comes from a discovery described in the second paper also published in ACS Nano as Reduction of Graphene Oxide via Bacterial Respiration. Andreas Lüttge, Rice professor of earth science and chemistry, had already been studying the effects of bacteria on carbon when James Tour came to him with idea that graphene oxide might become a prominent form of carbon nanotechnology. This would mean its widespread use and distribution throughout the environment. Was there any biological way of controlling graphene oxide?
As it turned out the answer was a comfortable ‘yes.’ Bacteria from the common bacteria genus Shewanella easily convert graphic oxide into simple graphene, which then arranges itself into graphite. Graphite is largely inert and harmless in the environment.
Thus graphene oxide, which apparently can be mass produced relatively easily and inexpensively, can find wide application in the knowledge that ‘cleanup’ can be accomplished by common naturally occurring bacteria. It’s a neatly green package. Now it needs to go toward the implementation steps – all of this has been lab work – but the Rice studies were developed in partnership with a Houston based oil drilling company, which has plans for the commercial use of the graphene oxide.