Bait, Hook, Destroy: Titanium Nanoparticles Embedded Mat Absorbs Pollutants from Water
While many parts of the world face major challenges due to limited freshwater availability, a significant amount of the limited freshwater resources in the world are contaminated by pollutants from industry, farming, energy generation, and other activities.
Now, researchers at the Rice University have developed a new “mat” that can adsorb and destroy pollutants from water.
The mat comprises titanium dioxide nanoparticles that are embedded into polymer fibers- to capture pollutants and, upon exposure to light, degrade them through oxidation into harmless byproducts.
The mat is made of spun polyvinyl fibers. The researchers made it highly porous by adding small plastic beads that were later dissolved with chemicals. The pores offer plenty of surface area for titanium oxide particles to inhabit and await their prey.
The mat’s hydrophobic (water-avoiding) fibers naturally attract hydrophobic contaminants like the endocrine disruptors used in the tests. Once bound to the mat, exposure to light activates the
photocatalytic titanium dioxide, which produces reactive oxygen species (ROS) that destroy the contaminants.“Current photocatalytic treatment suffers from two limitations,” said Rice environmental engineer and NEWT Center Director Pedro Alvarez. “One is inefficiency because the oxidants produced are scavenged by things that are much more abundant than the target pollutant, so they don’t destroy the pollutant. Second, it costs a lot of money to retain and separate slurry photocatalysts and prevent them from leaking into the treated water,” he said. “In some cases, the energy cost of filtering that slurry is more than what’s needed to power the UV lights.”
“We solved both limitations by immobilizing the catalyst to make it very easy to reuse and retain,” Alvarez said. “We don’t allow it to leach out of the mat and impact the water.”
The mat also would allow treatment plants to perform pollutant removal and destruction in two discrete steps, which isn’t possible with the slurry, Alvarez said. “It can be desirable to do that if the water is murky and light penetration is a challenge. You can fish out the contaminants adsorbed by the mat and transfer it to another reactor with clearer water. There, you can destroy the pollutants, clean out the mat and then return it so it can fish for more.”
