According to foreign media reports, Rice University researchers have invented a new kind of "fiber mat", which is magical in that it can adsorb and destroy pollutants in water. This "purifier" consists of titanium dioxide nanoparticles embedded in polymer fibers. During testing, the research team demonstrated that the material can indeed adsorb pollutants. However, it is not water that is used, but titanium dioxide nanoparticles can be exposed to ultraviolet light to destroy the pollutants. Compared to other systems, this design is faster, safer, and energy efficient.
In fact, titanium dioxide is a relatively high-yield purification material.
When exposed to ultraviolet light, it can act as a photocatalyst, releasing reactive oxygen species (ROS) to break down pollutants. Over the years, this ability has been applied to microfluidic filters, building smoking panels, and fabric coatings that allow us to dry clothes in the sun.
In this example, titanium dioxide nanoparticles are embedded in a high-permeability polyethylene fiberboard to remove and kill interferences. Given the hydrophobic nature (water resistance) of the fibers, this means that they will not absorb moisture but will absorb pollutants.
After these mats adsorb the pollutants and irradiate them with ultraviolet light, the photocatalytic reaction that destroys the pollutants can be triggered. Titanium dioxide has been used in water treatment for a long time, but usually a large amount of raw material needs to be added to the wastewater (to form a slurry).
The fiber mat can be adsorbed before the embedded titanium dioxide nanoparticles begin to destroy the contaminants.
After the photocatalysis step is completed, the treated water needs to be filtered out of the mud again, which is difficult and inefficient. According to Pedro Alvarez, one of the study authors, current photocatalytic treatments have two major limitations in efficiency:
First, the oxidant produced is much richer than the target pollutant, so it cannot destroy the pollutant. Second, it takes a lot of time and money to maintain and separate the slurry-like photocatalyst to prevent it from leaking into the treated water.
In some cases, the energy cost of filtering mud is much more than what is needed for UV light. In view of this, the research team resolved by fixing the catalyst to make it easy to reuse and retain-"We do not allow it to filter out of the mat and affect the water."
Titanium dioxide nanoparticles enter the pores of the textile
In addition to being faster, researchers also claim that the new technology can save more energy, especially when dealing with dirtier water. From distilled water to wastewater from water treatment plants, fiber mats need only double their energy. (By comparison, the slurry requires 11 times)
If the contamination is too thick and it is difficult for UV light to reach the location of the nanoparticles, the new technology also supports a two-step process. According to Alvarez, if the water is turbid, light penetration can be a challenge, which is necessary:
You can remove the pollutants trapped by the mat, then transfer it to another reactor with cleaner water, then destroy the pollutants, clean the mat, and then take it back to use.