title: Influence of cations on the partition behavior of perfluoroheptanoate (PFHpA) and perfluorohexanesulfonate (PFHxS) on wastewater sludge.
abstract: The effects of different cations on the sorption behavior of PFHpA and PFHxS on two types of sludge were investigated in this study. The sodium and potassium ions did not significantly affect PFHpA and PFHxS sorption on different sludge. For calcium and magnesium, the sorption amount of PFAS increased with calcium and magnesium concentration increasing from 1 to 30 mM and then decreased with those increasing from 30 to 100 mM. The sorption level of PFHxS or PFHpA greatly increased with increasing Al3+ and Fe3+ cation concentrations due to the strong sorption and coagulation effects by the formation of aluminum hydroxide (or ferric hydroxide) colloids or precipitates. After the organics in sludge has been removed by thermal treatment, the PFAS sorption on sludge was greatly reduced. Such finding indicated that sorption to organic matter is more important for anionic PFASs than adsorption to mineral surfaces. However, due to the higher content of biological organics, a secondary activated sludge has higher affinity toward PFAS species than chemically enhanced primary treatment sludge. It indicated that the organic types in sludge were also crucial to the sorption levels of PFASs by sludge.
authors.affiliation: School of Environment, Jinan University, Guangzhou, China; Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong. Electronic address: feiwang1984@gmail.com.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.
authors.forename: Kaimin
authors.initials: K
authors.lastname: Shih
authors.affiliation: Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.
authors.forename: Ruowei
authors.initials: R
authors.lastname: Ma
authors.affiliation: Department of Civil Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong.
authors.forename: Xiao-yan
authors.initials: XY
authors.lastname: Li
mesh_terms: D000327:Adsorption; D002412:Cations / Q000737:chemistry*; D005466:Fluorocarbons; D006538:Heptanoic Acids / Q000737:chemistry*; D007477:Ions; D008903:Minerals; D012722:Sewage / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry*
chemical_list: D002412:Cations; D005466:Fluorocarbons; D006538:Heptanoic Acids; D007477:Ions; D008903:Minerals; D012722:Sewage; D013451:Sulfonic Acids; D062065:Wastewater; C471071:perfluorohexanesulfonic acid
keywords: Cation; PFHpA; PFHxS; Partition; Sludge; Sorption