A collaborative team of researchers used the wonder material graphene to solve one of the world’s biggest problems: clean water. The team developed a graphene-based coating for use in desalination membranes which could lead to reliable clean water solutions.
Graphene: Fixing Filtration on the Small Scale
The new membrane is far superior and scalable than current nanofiltration membrane technologies. The research could also have applications for protein separation, wastewater treatment and pharmaceutical and food industry applications. Mauricio Terrones, professor of physics, chemistry and materials science and engineering at Penn State said these membranes would be elevated in a way not seen before.
"Our dream is to create a smart membrane that combines high flow rates, high efficiency, long lifetime, self-healing and eliminates bio and inorganic fouling in order to provide clean water solutions for the many parts of the world where clean water is scarce. This work is taking us in that direction," Terrones noted.
The membrane is created using a mixture of graphene oxide and few-layered graphene in liquid sprayed onto a backbone support membrane of polysulfone modified with polyvinyl alcohol. The support membrane increases the sturdiness of the hybrid membrane. The completed product is able to stand up to intense cross-flow, high pressure and chlorine exposure. In its testing mode, the membrane was able to reject 85 percent of salt a level adequate for agricultural purposes but still too saline for drinking. It was able to reject 96 percent of dye molecules. This latter figure will be crucial in the task of cleaning waterways polluted by dyes from textile manufacturing.A common occurrence in some areas of the world.
The 'Wonder Material' Doing More 'Wonder'-ful Things
Graphene was discovered in 2004 and was soon being used in a wide range of applications. At this point, it's become known as the wonder material for the engineering communities. It possesses a unique set of properties, amongst them is the ability to efficiently conduct electricity. In this instance, a membrane of 100 percent graphene is expected to have 100 percent salt rejection, which would make it the perfect desalination tool. However, the material is presently difficult to scale up as it's currently too expensive to use at a manufacturing level.
Other applications for graphene have so far included super fast transistors that could increase the power of your computer more than 100 times. As well as batteries to be printed directly onto fabric for use with wearable technology and 2d magnets that will revolutionize storage capacity. The research was published online on August 28 in Nature Nanotechnology describing their work titled "Effective NaCL and dye rejection of hybrid graphene oxide/graphene layered membranes."
The research was published online on August 28 in Nature Nanotechnology describing their work titled "Effective NaCL and dye rejection of hybrid graphene oxide/graphene layered membranes."
First author Aaron Morelos-Gomez says, "Our membrane overcomes the water solubility of graphene oxide by using polyvinyl alcohol as an adhesive making it resistant against strong water flow and high pressures. By mixing graphene oxide with graphene we could also improve significantly its chemical resistance."
Professor Morinobu Endo concludes that "this is the first step towards more effective and smart membranes that could self-adapt depending on their environment."