Perfluorooctanoic acid (PFOA), a highly toxic water pollutant caused a number of U.S. communities to close their drinking water supplies. The carcinogen used in Teflon production and other industrial processes as well as its environmental persistence. PFOA contamination is an extensive problem worldwide.
Now researchers report an inexpensive and renewable material that rapidly removes PFOA from water. The novel treatment effectively eliminates the micropollutant to below 10 parts per trillion.
The material extracts the pollutant out of water, said, William Dichtel from Northwestern University. The polymer contains sites that bind PFOA strongly, which strips this pollutant out of water even when presenting at extremely low concentrations. The binding sites are joined together by linkers that further enhance the affinity for PFOA.
Researchers believe the material can support water purification efforts to rid drinking water of PFOA and perhaps other polyfluorinated alkyl substances (PFASs).
The Environmental Protection Agency (EPA) 2016 advisory said, the combined concentration of PFOA and PFOS in drinking water is 70 parts per trillion, which is equal to one teaspoon of PFOA in 14 Olympic-sized swimming pools.
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In studies of PFOA exposure, negative health effects noted at lower concentrations than the EPA advisory limit. Four states, Minnesota, New Hampshire, New Jersey and Vermont have implemented limits of at least half the EPA limit.
The polymer can be regenerated and reused multiple times. Only a modest amount of the material is needed to capture and remove PFOA to less than 10 parts per trillion.
The material has more than 10 times higher affinity for PFOA than activated carbon, a conventional treatment method with several known deficiencies.
The networked polymer joining smaller molecules with tiny pores, and selectivity is programmed into the material through a crosslinked monomer. The main component, beta-cyclodextrin, is a naturally occurring bio-renewable sugar molecule derived from cornstarch.
In many communities PFOA levels exceed the EPA’s advisory limit. In 2016, Hoosick Falls, New York, and Bennington, Vermont, declared states of emergency because of PFOA-contaminated drinking water.
More information: [JACS]