Enhanced removal of perfluorooctane sulfonic acid and perfluorooctanoic acid via polyelectrolyte functionalized ultrafiltration membrane: Effects of membrane modification and water matrix

•PAH/PAA modification resulted in membrane MWCO and porosity reductions.•30 % increase in PFOS and PFOA removal compared to unmodified UF due to size exclusion.•Coexistence of cations and HA caused significantly higher removal of PFOS and PFOA.•Size/charge exclusion of PFOS-cation-PFOS, PFOS-cation-HA, PFOA-cation-HA complexes.