Enhanced selective removal of PFAS at trace level using quaternized cellulose-functionalized polymer resin: Performance and mechanism

Abstract

The effective protocol for treating per- and polyfluoroalkyl substances (PFAS) in water at environmentally relevant concentrations (∼ ng L⁻¹) has received unprecedented attention due to the stringent drinking water standards. In order to ensure safe water treatment, sorption using quaternary ammonium functionalized strong-base anion exchange resins (SB-AERs) is considered a viable option for treating PFAS when compared to commercialized activated carbon, as SB-AERs can be in situ regenerated with long-term operation capabilities. However, the harsh conditions required for traditional direct synthesis of SB-AERs (such as prolonged reaction times, complex processes, and environmental pollution caused by the organic reagents used) limit their applications. In this study, we present a novel indirect synthesis method that can effectively pre-functionalizes cellulose for quaternization. This modified cellulose is subsequently loaded onto chloromethylated polystyrene to produce a quaternized cellulose-functionalized polymer resin (QC-CMPS). The process is straightforward to implement, reduces the use of toxic chemicals, and effectively mitigates water safety risks associated with hazardous reagent leaks. As results, the prepared QC-CMPS demonstrates exceptional selective capability for PFAS removal in real environmental water matrices, achieving over 99 % removal efficiency at an initial concentration of 1000 ng L⁻¹. Additionally, QC-CMPS demonstrates low sensitivity to pH and background ions, effectively removing PFAS from both tap water and lake water with efficiency rates exceeding 95 %. The exhausted QC-CMPS can be readily rejuvenated by rinsing with 1 % NaCl and MeOH (V/V=3/7) mixture, as demonstrated by five successful consecutive cycles. The fixed-bed column test confirmed that ∼ 11,000 bed volumes (∼ 292.70 L) of the feed streams (∼250 ng L⁻¹) can be effectively treated with the enrichment factor of 26.42, 25.16, 27.77 and 21.17 for PFOA, PFOS, PFBS, and GenX, respectively, highlighting significant potential for practical applications.