New filtration technologies could absorb ‘forever chemicals’ at ‘ultrafast’ rate
New filtration technologies have been developed that can absorb “forever chemicals” at an “ultra-fast” rate.
The researchers say their findings could greatly improve pollution control, but they face many challenges before the technology can be implemented on a large scale.
In a new paper, scientists outline how a layered double hydroxide (LDH) material made of copper and aluminum can absorb long-chain PFAS at an “ultra-fast” rate.
According to reports, this could be up to 100 times the rate of current filtration systems.
Chemicals called “Forever Chemicals” because they do not degrade have been used in a variety of consumer and commercial applications since the 1950s. They can repel water and oil, withstand high temperatures, and act as “surfactants” by helping different types of liquids mix.
There are approximately 15,000 different PFAS chemicals. Each has a slightly different chemical composition, but all contain at least two carbon-fluorine bonds. These extremely strong bonds mean that PFAS will not break down easily. So the bond that gives PFAS some of their unique properties also causes them to form and persist in our bodies and environments for decades.
Many PFAS are known to be toxic, including their association with altered liver and thyroid function and various cancers.
Granular activated carbon, reverse osmosis and ion exchange are among the available filtration technologies and work by absorbing PFAS in water. However, chemicals captured in the filter must be stored in hazardous waste facilities or destroyed through a thermal process using high heat; this produces toxic byproducts or breaks down PFAS into smaller PFAS.
According to Michael Wong, director of the Rice University Water Institute, a PFAS research center that develops new technologies, the new process works by absorbing and concentrating PFAS at high levels; This means it is non-thermal in that chemicals can be destroyed without the use of high temperatures.
The LDH material is similar to those used before, but some of the aluminum atoms have been replaced by copper atoms, so the positively charged material attracts and absorbs a wide range of negatively charged PFAS.
“It absorbs it 100 times faster than other existing materials,” Mr Wong said. said Guard.
PFAS was considered virtually indestructible due to bonds between carbon and fluoride atoms, but the team found that heating the material to a relatively low temperature of 400 to 500°C broke the bonds, leaving a safe, disposable byproduct.
Additionally, new PFAS elimination systems generally do not work at scale, but the researchers say the LDH material has a strong absorption rate and can be used repeatedly and with existing infrastructure, eliminating a major cost barrier.
“This material will be important in driving research into PFAS degradation in general,” Mr Wong added.
