Soaking Up Oil Spills

Aerogels made a splash in the mainstream media a few years back when cleanup crews considered using them to mop up the Deepwater Horizon oil spill in the Gulf of Mexico. Aerogels still haven’t been used to clean up oil spills. But patents show the time may be close.

In 2002, researchers at Lawrence Livermore National Laboratory (LLNL) filed a patent for a method to recover oil from spills using hydrophobic sol-gels and aerogels (U.S. Patent Application No. 20020185444). The hydrophobic aerogels, synthesized from tetramethylorthosilicate and (3,3,3-trifluoropropyl)trimethoxysilane, could absorb significant amounts of oil from mixtures of oil and salt water: The CF₃-functionalized aerogel absorbed oil from mixtures of crude oil and saltwater in ratios as high as 237 parts oil to 1 part aerogel.

In a later patent granted in 2007 to LLNL (U.S. Patent No. 7211605), the same researchers claim that fluorinated silica aerogels are an alternative to the standard granulated activated carbon methods for extracting organic liquids from aqueous solutions. The researchers show that the water-shedding properties of the hydrophobic silica aerogels provide a more efficient separation of organic materials from water. They postulate that this separation occurs by preferential transport of the organic vapors across the liquid-solid boundary at the surface of the hydrophobic aerogel.