New "superhydrophobic" graphene material can separate oil from water

Researchers at the Indian Institute of Technology Guwahati claim they have developed a graphene-based "superhydrophobic" material that can separate oil and water. The material could have various uses in industry and healthcare.

Superhydrophobic materials materials with extreme water repellency are considered the best for removing oil from water, but they are generally not scalable, use environmentally toxic products such as fluorinated polymers, or have poor mechanical and chemical stability.

The IIT Guwahati team manipulated graphene to have superhydrophobic properties suitable for separation of oil from water in emulsions. The team developed a method to produce graphene oxide-polymer composite with "hierarchical topography and low surface energy chemistry in the confined space". They further deposited iron oxide nanoparticles on the two dimensional nanosheets, which made the entire material magnetically active.

Our graphene oxide composites were able to separate oil from water in emulsions with high efficiency, said Dr. Manna, adding that this was uniquely done under extremes of pH, salinity and surfactant contaminations as in real-life situations.

This graphene oxide species was capable of selectively soaking up tiny crude-oil droplets in oil-to-water emulsions with high absorption capacity (above 1000 wt%), as well as coalescing larger oil droplets of emulsions from water-in-oil emulsions, the institute claimed.