Sorption of Perfluorooctane sulfonate (PFOS)including its isomers on hydrargillite as a function of pH,humic substances and Na2SO4

• 作者: Jean-Noel Uwayezu Leo W.Y.Yeung Mattias B(a)ckstr(o)m
• 来源期刊: 环境科学学报（英文版）
• 年，卷（期）: 2022,（1）
• 页码范围: 263-272
• 页数: 10页
• 语种: 英文

摘要

Perfluooroctane sulfonate (PFOS) is a persistent organic pollutant (POP) and emergent con-taminant that are widespread in the environment.Understanding the mechanisms control-ling the distribution of PFOS and its isomers between hydrargillite and the water phase is important in order to study their redistribution and mobility in the environment.This study investigated the effects of pH,humic acid,fulvic acid and Na2SO4 on sorption of PFOS iso-mers to hydrargillite.A mixture of PFOS isomers was spiked into water and hydrargillite was added to the system and shaken for one day;the system was tested with different aqueous composition.Concentrations of PFOS isomers in the aqueous phase were quanti-fied using an ultra-performance liquid chromatograph coupled to a triple quadrupole mass spectrometer.Our results showed that the distribution coefficients of PFOS isomers were found to be 0.76,0.71,0.93 and 0.90 at pH 6.5,for 3-/4-/5-PFOS,6-/2-PFOS,L-PFOS and to-tal PFOS respectively.The distribution coefficients increased at lower pH and decreased at alkaline conditions.The presence of humic substances (HS) increased the sorption slightly at the environmental pH of 6.5,although a competition effect was observed during acidic conditions.A tendency of PFOS distribution to hydrargillite in the presence of Na2SO4 was like its behavior in the presence of HS although the mechanisms behind the sorption were interpreted differently.This study revealed that L-PFOS was readily sorbed when no other chemicals were added or in 20 mg/L FA or 100 mg/L Na2SO4.We suggest that an increase in PFOS sorption in the presence of HS may be due to hydrophobic mechanisms while Na2SO4 contributed to increased sorption through ionic strength effects.