Sorption of perfluorooctane sulfonate and perfluorooctanoate on activated sludge

Sorption of perfluoroalkyl substances in sewage sludge

“…The linearity of the sorption isotherms was quantitatively confirmed by fitting parameter N of the Freundlich model, which was close to 1 (Table 3). with previous results (Zhang et al, 2013), in which K d values for PFOA ranged from 13 -68 mL g -1 , while K d values up to one order of magnitude higher were obtained by other authors (Yu et al, 2009;Zhou et al, 2010;Arvaniti et al, 2012;Arvaniti et al, 2014), as already discussed for PFOS. However, our results agreed with the finding that PFOA had a lower sorption affinity for sludge than PFOS.…”

“…The sorption data of PFASs in sludge has scarcely been reported to date, and results indicated that sorption solid-liquid distribution coefficients (K d ) may vary by up to three orders of magnitude, depending on the physicochemical characteristics of the PFASs, the sludge properties (digestion treatment) and the PFAS levels in wastewater. Moreover, the sorption mechanisms were not clearly determined due to the hydrophobic and hydrophilic nature of the PFASs (Ochoa-Herrera and Sierra-Alvarez, 2008; Zhou et al, 2010;Zhang et al, 2013). Other than the limited information about the sorption of PFASs in sludge, to the best of our knowledge, no data are available on the sorption reversibility of PFASs in sludge, although in situ K d data regarding the suspended matter of sludge and wastewater in contact are available (Arvaniti et al, 2012).…”

Occurrence of organic microcontaminants in the wastewater treatment process. A mini review

“…According to Guo et al [90], this could be due to the higher organic carbon-normalised distribution coefficient of perfluoroalkylsulfonate (PFASs) in comparison with the carboxylate analog, a sign of preferential uptake of PFASs by the sludge, which seems to be a key mechanism in the process. Although Zhou et al [92] state that, in terms of electrostatic interaction, PFOS and PFOA would suffer repulsion, making their adsorption impossible on activated sludge, they also consider that some cations present in the sludge (e.g. Ca 2+ and Mg 2+ ) could provide the necessary ion bridges to allow the sorption of the negatively charged PFCs.…”

Assembling structures and dynamics properties of perfluorooctane sulfonate (PFOS) at water–titanium oxide interfaces

“…Different from other POPs, PFOS are highly water-soluble and thus are easy to transport in the aquatic environment [5]. Therefore, the solidwater interfacial process is believed to be a critical factor determining the toxicity and environmental fate of PFOS and has been subjected to intense investigation [6][7][8][9].…”