An
intrinsically porous polymer with a very high internal surface area could be an
ideal material for soaking up spilled oil. Researchers from KAUST have
identified a polymer that can be formed into robust, reusable mats to rapidly
adsorb spilled oil, fuel, or organic solvents from the surface of fresh or salt
water.
"Oil
spills remain a global threat to marine habitats, human health and
livelihoods," says Gyorgy Szekely from KAUST's Advanced Membranes and
Porous Materials Center, who led the research. "Even though most spilled
oil floats on the water surface, a small percentage of the oil is dispersed
naturally in water, affecting the marine ecosystem, including fish and
plankton," Szekely says. "Such ecological disasters have led to a
great need to discover high-performance sorbents for rapid and high-efficiency
cleanup from the sea surface."
To develop
a more effective oil-adsorbent material, the team exploited a polymer called
6FDA-TrMPD, which has two key features important for soaking up spilled oil.
"Our materials—unlike most other materials reported for the cleanup of oil
spills—are intrinsically porous," explains Fuat Topuz, a postdoc in
Szekely's team. The team used a process called electrospinning to convert a
solution of the polymer into robust mats, which incorporated an extensive
network of pores within the polymer's fibrous structure, creating a vast
surface area of 565 square meters per gram of material for adsorbing oil.
Secondly,
the polymer's molecular structure incorporated water-repellent trifluoromethyl
groups, which caused the material's adsorptive properties to reject water while
strongly soaking up nonpolar liquids, such as oil floating on the water's
surface.
In
testing, the material could rapidly and efficiently clean up oil spills on
water. Within a few minutes of their deployment, the mats adsorbed spills with
a capacity of between 25 and 56 grams of oil, or nonpolar solvent, per gram of
polymer. "The sorption performance of the material is much better than
many reported adsorbents, and the materials could be recycled and reused with
similar performance, demonstrating their great potential for cleanup of oil
spills and nonpolar solvents," Topuz says.
"In
our next step, we will process these materials further to create membranes and
fibrous sponges to make easily recoverable adsorbents while preserving their
high performance," Szekely says. The team is also developing adsorbent
materials made from sustainably sourced polymers and expanding the range of
pollutants that the materials can capture to include removing organic micropollutants
and heavy metals from water.