title: Comparative sorption and desorption behaviors of PFHxS and PFOS on sequentially extracted humic substances.
abstract: The sorption and desorption behaviors of two perfluoroalkane sulfonates (PFSAs), including perfluorohexane sulfonate (PFHxS) and perfluorooctane sulfonate (PFOS) on two humic acids (HAs) and humin (HM), which were extracted from a peat soil, were investigated. The sorption kinetics and isotherms showed that the sorption of PFOS on the humic substances (HSs) was much higher than PFHxS. For the same PFSA compound, the sorption on HSs followed the order of HM>HA2>HA1. These suggest that hydrophobic interaction plays a key role in the sorption of PFSAs on HSs. The sorption capacities of PFSAs on HSs were significantly related to their aliphaticity, but negatively correlated to aromatic carbons, indicating the importance of aliphatic groups in the sorption of PFSAs. Compared to PFOS, PFHxS displayed distinct desorption hysteresis, probably due to irreversible pore deformation after sorption of PFHxS. The sorption of the two PFSAs on HSs decreased with an increase in pH in the solution. This is ascribed to the electrostatic interaction and hydrogen bonding at lower pH. Hydrophobic interaction might also be stronger at lower pH due to the aggregation of HSs.
authors.affiliation: Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China. Electronic address: zhaolixia1982@163.com.
authors.forename: Lixia
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China.
authors.forename: Shuhong
authors.initials: S
authors.lastname: Fang
authors.affiliation: Key Laboratory of Pollution Processes and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China. Electronic address: zhuly@nankai.edu.cn.
authors.forename: Lingyan
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Zhengtao
authors.initials: Z
authors.lastname: Liu
mesh_terms: D000327:Adsorption; D017738:Alkanesulfonic Acids / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry*; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012989:Soil Pollutants / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D017738:Alkanesulfonic Acids; D005466:Fluorocarbons; D006812:Humic Substances; D012989:Soil Pollutants; D013451:Sulfonic Acids; C471071:perfluorohexanesulfonic acid; C076994:perfluorooctane sulfonic acid
keywords: Desorption; Humic substances (HSs); Perfluorohexane sulfonate (PFHxS); Perfluorooctane sulfonate (PFOS); Sorption