Performance and mechanisms for removal of perfluorooctanoate (PFOA) from aqueous solution by activated carbon fiber

Abstract

18 Sorption behaviors of perfluorooctanoate (PFOA) by activated carbon fiber (ACF) in 19 aqueous solution were investigated. The sorption of PFOA on ACF followed 20 pseudo-second-order kinetics and the sorption equilibrium reached at approximately 6 h. The 21 sorption of PFOA on ACF fitted the Freundlich model well. The sorption capacity of PFOA by 22 ACF decreased with the increasing pH, indicating that electrostatic attractive (pH < 7.4) and 23 repulsion (pH > 7.4) existed in the sorption process. Dissolved organic matter (DOM) inhibited 24 the sorption of PFOA on ACF and no obvious sorption was observed when the concentration of 25 DOM was increased to 500 mg L -1 . This was primarily because of the competitive sorption 26 between DOM and PFOA, and the blockage of ACF pore by DOM. The results indicated that 27 electrostatic interactions, hydrogen bonding interaction, and hydrophobic interaction were 28 responsible for the fast sorption, and the formation of hemi-micelles and micelles of PFOA 29 further promoted the sorption of PFOA on ACF.30

Sorptive remediation of perfluorooctanoic acid (PFOA) using mixed mineral and graphene/carbon-based materials

“…A variety of results have been reported for the effect of pH on PFOA-sorption depending on the type of adsorbent. Sorption onto activated carbon fibres and single-walled carbon nanotubes (CNTs) decreased by 12 % and 32 %, respectively (Deng et al 2012;Wang et al 2015), when the pH was increased from 3 to 9 (attributed to increased repulsion), whereas sorption onto powdered activated carbon was relatively unaffected (Deng et al 2012), owing to a stable zeta potential in that pH range. A study comparing sorption of PFASs onto different types of CNTs found that pristine CNTs showed greater sorption compared with hydroxyl and carboxylfunctionalised CNTs (Deng et al 2012), which demonstrated the role of hydrophobic interactions in PFAS-sorption by carbonaceous adsorbents.…”

“…As degradation of these chemicals is an energy-intensive process and presents challenges especially for use in situ, adsorption is a cost-effective strategy to manage PFOA contamination in situ by reducing contaminant mobility. Sorption of PFOA onto surfaces of carbonaceous materials (like chars, activated-C and nanotubes) (Deng et al 2012;Wang et al 2015) have been demonstrated, with granular activated-C used most commonly for the treatment of PFASs in ex situ filtration systems. These rely on hydrophobic interactions at the non-polar C-phase (Kucharzyk et al 2017).…”

Microplastics with adsorbed contaminants: Mechanisms and Treatment

“…The inhibition of PFOA sorption on active carbon fiber by OM was reported in a study where no obvious sorption occurred with increasing OM concentration to 500 mg L −1 ( Wang et al., 2015a ). These results support competitive sorption between OM and PFOA, and the pore blockage of active carbon fiber by OM.…”

“…As indicated in Fig. 2 (a) ( Wang et al., 2015a ; Llorca et al., 2018 ), hydrophobic interaction between MPs and PFAS generally increased the adsorption affinity of MPs on longer-chain compounds. Although the effect of salinity should not be overlooked, adsorption of PFAS on PS in freshwater was higher than on PE and PVC.…”

“…Although hydrophobic OM was found to enhance PFAS retention in granular activated carbon (GAC) adsorption, hydrophilic OM did not appear to significantly affect PFAS adsorption on both GAC and anion exchange (AE) ( Kothawala et al., 2017 ). Nonetheless, several studies indicated that the presence of OM may reduce the sorption of PFAS on active carbon fiber, because OM could compete for active sites or cause pore blockage ( Wang et al., 2015a ; Yang et al., 2013 ).…”