title: Treatment of sites contaminated with perfluorinated compounds using biochar amendment.
abstract: Per- and polyfluorinated compounds (PFCs) have been attracting increasing attention due to their considerable persistence, bioaccumulation, and toxicity. Here, we studied the sorption behavior of three PFCs, viz. perfluorooctanesulfonic acid (PFOS), perfluorooctanecarboxylic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), on one activated carbon (AC) and two biochars from different feedstocks, viz. mixed wood (MW) and paper mill waste (PMW). In addition, we explored the potential of remediating three natively PFC contaminated soils by the addition of AC or biochar. The sorption coefficient i.e. Freundlich coefficients LogKF, (μg/kg)/(μg/L)(n), for the two biochars were 4.61±0.11 and 4.41±0.05 for PFOS, 3.02±0.04 and 3.01±0.01 for PFOA, and 3.21±0.07 and 3.18±0.03 for PFHxS, respectively. The AC sorbed the PFCs so strongly that aqueous concentrations were reduced to below detection limits, implying that the LogKF values were above 5.60. Sorption capacities decreased in the order: AC>MW>PMW, which was consistent with the material's surface area and pore size distribution. PFC sorption to MW biochar was near-linear (Freundlich exponent nF of 0.87-0.90), but non-linear for PMW biochar (0.64-0.73). Addition of the AC to contaminated soils resulted in almost complete removal of PFCs from the water phase and a significant (i.e. 1-3 Log unit) increase in soil-water distribution coefficient LogKd. However, small to no reduction in pore water concentration, and no effect on LogKd was found for the biochars. We conclude that amendment with AC but not biochar can be a useful method for in situ remediation of PFC-contaminated soils.
authors.affiliation: Norwegian Geotechnical Institute, P.O. Box 3930 Ullevål Stadion, 0806 Oslo, Norway.
authors.forename: Darya
authors.initials: D
authors.lastname: Kupryianchyk
authors.affiliation: Norwegian Geotechnical Institute, P.O. Box 3930 Ullevål Stadion, 0806 Oslo, Norway.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Hale
authors.affiliation: Norwegian Geotechnical Institute, P.O. Box 3930 Ullevål Stadion, 0806 Oslo, Norway; Department of Geosciences, University of Oslo, P.O. Box 1047 Blindern, N-0316 Oslo, Norway.
authors.forename: Gijs D
authors.initials: GD
authors.lastname: Breedveld
authors.affiliation: Norwegian Geotechnical Institute, P.O. Box 3930 Ullevål Stadion, 0806 Oslo, Norway; Institute for Environmental Sciences (IMV), Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway; Department of Applied Environmental Sciences (ITM), Stockholm University, 10691 Stockholm, Sweden. Electronic address: Gerard.Cornelissen@ngi.no.
authors.forename: Gerard
authors.initials: G
authors.lastname: Cornelissen
mesh_terms: D002606:Charcoal / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry* / Q000302:isolation & purification; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry* / Q000302:isolation & purification; D014866:Waste Products; D014934:Wood / Q000737:chemistry
chemical_list: D005466:Fluorocarbons; D012987:Soil; D012989:Soil Pollutants; D014866:Waste Products; C540010:biochar; D002606:Charcoal
keywords: Activated carbon; Biochar; PFOS; Perfluorinated compounds; Soil remediation; Sorption