Researchers from Japan have for the first time created a ‘marshmallow-like’ superhydrophobic aerogel that acts effectively as a sponge to soak up hydrocarbons and can then be ‘wrung out’ and reused.
Previous materials of this type have been created with varying success due to shortcomings that would affect large-scale clean up (for example, on the scale of the 2010 BP Deepwater Horizon oil spill in the Gulf of Mexico) including a lack of hydrophobicity, expensive production methods and a one use limit.
The material was first reported in 2011 when the research team was working on developing flexible and transparent aerogels, and unintentionally made the opaque material that has ‘remarkable’ oil-absorbing properties. When testing the separation of hexane from water, the researchers discovered that the material removed all the hexane without changing the amount of water due to its superhydrophobicity. The material has yet to be tested on viscous crude oil as it is not readily available, and was instead tested on a mineral oil similar to medium crude oil, which resulted in a slow but unproblematic absorption.
The marshmallow is made in a simple and inexpensive process using reagents that can be obtained fairly easily, although it is not a continuous process, which would prove problematic when the material is required in bulk in a limited time – such as for a large oil spill. The most important characteristic of the material is its ability to be wrung out and reused. It also boasts a wide temperature stability of around 300°C to -196°C. Its use is also not limited to mopping up oil from oil spills – other instances require the removal of organic compounds from an aqueous medium would also make use of the material (such as the treatmet of waste water from industrial processes), which could be tailored using chemicals for a vast array of applications.
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