Highly efficient sorption of perfluorooctane sulfonate and perfluorooctanoate on a quaternized cotton prepared by atom transfer radical polymerization

Removal of perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) from wastewater has caused great attention in recent years. In this study, quaternized cotton highly effective for the removal of PFOS and PFOA from aqueous solution was prepared by surface-initiated atom transfer radical polymerization (ATRP). The successful graft of long polymer brushes on the cotton surfaces was verified by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). XPS analysis indicated that the high density of quaternary ammonium cations on the long polymers grafted onto the cotton surface were responsible for the enhanced sorption of PFOS and PFOA. This novel quaternized cotton exhibited fast sorption and high sorption capacity for PFOS and PFOA. The sorption equilibrium of PFOA and PFOS on quaternized cotton was achieved at 4 h and 12 h, respectively, much faster than that on the porous adsorbents reported. The obtained maximum sorption capacities of PFOS and PFOA on quaternized cotton at pH 5.0 were 3.3 and 3.1 mmol/g, respectively. Additionally, solution pH in the range of 3.0–10.0 had little effect on their high sorption. This quaternized cotton has promising application for the removal of perfluorinated compounds from wastewater.