Per- and polyfluoroalkyl substances (PFAS) is a class of anthropogenic chemicals contained in waterproof coatings, aqueous film-forming foam used in firefighting, and numerous other consumer products. The very properties that make PFAS indispensable in industrial applications—such as their chemical stability and resistance to degradation—are also those that pose significant risks to environmental and human health, as they persist in nature and bioaccumulate in ecosystems and organisms. Current treatment methods to remove PFAS include reverse osmosis (RO), ion exchange resins (IX), and granulated activated carbon (GAC). However, RO and IX methods are costly, and GAC treatment is limited by its single-use nature due to its expensive regeneration process. This study presents the design, validation, and experimentation of a rapid small scale column testing (RSSCT) system to evaluate the removal of long- and short- chained PFAS by modified cellulose sponge sorbents. RSSCT systems are designed to emulate the performance of larger scale water treatment systems at a fraction of the size while using significantly less influent water and sorbent media. Important design factors, such as hydraulic retention time, are controlled by modulating the volumetric flow rate and column dimensions.
Samples of column effluent were taken frequently throughout the multi-day experiments and were analyzed using liquid chromatography-mass spectrometry (LC/MS) to establish breakthrough time of the different modified sponges and GAC. Preliminary results showed that activated sponges with hydroxyl end groups had comparable PFAS removal performance to that of GAC in repeated studies lasting up to 9 days, the equivalent of over 10,000 bed volumes of effluent, without breakthrough. Long-term experimental tests are currently being analyzed to compare the breakthrough times of these two materials. Our current results show that modified cellulose sponges have the potential to be comparably effective to the current industrial standard, GAC.
