Sorption of perfluorinated compounds from contaminated water to activated carbon

• Perfluorinated compounds (PFC) are toxic and bioaccumulative compounds that are ubiquitous in the environment. It is important to develop effective techniques to remove PFC from water. This study is the first to investigate sorption of PFC to activated carbon (AC) at environmentally relevant nanogram per liter concentrations. Batch AC sorption isotherms were measured for water from a contaminated groundwater well, for three perfluorosulfonates and five perfluoroacetic acids. For perfluorooctane sulfonate and perfluorooctanoic acid Freundlich sorption coefficients, log K (iF), for powdered activated carbon (PAC) were 4.0 and 3.8 (ng/g)(ng/L)(-n) , respectively, and for granular activated carbon (GAC) were 2.7 and 2.3 (ng/g)(ng/L)(-n) , respectively. Sorption was nonlinear, with Freundlich n coefficients generally around 0.5. The K (iF) on both GAC and PAC were PFC chain-length dependant, with increasing number of carbon yielding increasing K (iF). This chain-length dependence appeared stronger for perfluorosulfonates than for perfluoroacetic acids. Tests with short (10 min) adsorption times still yielded substantial PFC removal (20-40% for GAC, 60-90% for PAC) and revealed that AC is probably suitable for PFC removal in flow-through systems. A perfluorinated polymer, Teflon, was also tested as a PFC removal agent but proved not to be effective for PFC-contaminated water purification.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Keyword

Activated carbon

Contaminated water

Isotherms

Perfluorinated compounds

Earth sciences

Geovetenskap

Applied Environmental Science

tillämpad miljövetenskap

Publication and Content Type

ref (subject category)

art (subject category)