Researchers at the University of Bath have discovered a re
newable, bio-based polymer membrane capable of efficiently
capturing toxic ‘forever chemicals’ from water and offering a
potential new route to more sustainable water treatment.
Perfluorooctanoic acid (PFOA), a member of the per- and
polyfluoroalkyl substances (PFAS) family and once commonly
used in non-stick coatings, has now been widely detected in
water sources worldwide. High levels of exposure have been
linked to cancers, hormone disruption and immune system
suppression, with governments around the world taking action to
protect people and the environment.
Unlike many conventional water treatment materials that
require frequent replacement or generate secondary waste, the
new bio-based membrane can trap and hold over 94% of PFOA
from water. It can later be treated with heat to remove the
trapped pollutants, allowing the polymer to be reused and
reprocessed into a new membrane.
The novel membrane is made from a network of nanofibres that
when placed in water, absorb moisture and swell, acting like a
tightening net to trap and hold the pollutants.
“What really surprised us was how this material responds when
it meets water,” says Dr Xiang Ding, of the Innovation Centre for Applied Sustainable Technologies (iCAST) at the University of
Bath, the study’s post-doctoral researcher and lead author.
“Traditional nylon materials, like nylon 6 or nylon 6.6 barely
change, but our bio-based nanofibres structurally reorganise
themselves and tighten. This feature gives them a remarkable
ability to trap stubborn PFAS right inside the polymer network –
and quickly.”‘Forever chemical’ pollution is notoriously hard to
treat. Current clean-up methods that use electricity, sunlight or
microbes to break down PFOA can be expensive and difficult to
use at scale. More conventional treatment methods, such as
activated carbon or ion-exchange resins, can remove PFAS but
often require frequent replacement or complex regeneration
processes. This water-activated trapping mechanism works
rapidly, capturing up to half of the PFOA present in an hour and
retaining it even after washing. The researchers also discovered
that the membrane can be regenerated through a heating and
respinning process, unlocking a reprocess-recycling ability that
recovers up to 93% of its original adsorption capacity.
“By using renewable, furan-based building blocks instead of
fossil-derived materials, we’ve shown that high-performance
PFAS removal can be combined with more sustainable polymer
design,” Dr Ding adds