Microfluidics-generated graphene oxide microspheres and their application to removal of perfluorooctane sulfonate from polluted water

Abstract

Monodisperse graphene oxide (GO) microspheres were synthesized via microfluidics technology as a novel adsorbent for rapid (in 2 min) and high efficiency (98%) removal of perfluorooctane sulfonate (PFOS) from water. This novel material is a potential solution for treatment of bioaccumulative organic polluted water. To achieve improved performance, Mg 2+ was introduced into GO, and the metal composite exhibited significantly improved PFOS removal efficiency owing to bridging and interaction between Mg 2+ and the PFOS molecules, which was supported by density functional theory and X-ray photoelectron spectroscopy (XPS). This facile strategy may be extended to the synthesis of other spheres with unique structural features for application in water treatment.

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

“…Consequently, FeG and RemB could also potentially be laid down in landfill sites as a barrierlining in multi-liner systems to mitigate the leakage or migration of landfill leachates into the water table. Previous research has demonstrated the applicability of GO for PFOS-sorption (Zhao et al 2016). In this study, we prove that the performance of GO can be improved through strategic mineral-functionalisation, which makes FeG a better adsorbent (for a variety of PFASs, as shown in the section Remediation of a contaminated-site water sample).…”

“…However, there is a lack of studies that investigate the use of GBMs for PFAS-sorption. One study has reported the use of graphene oxide (GO), the most common graphene-derivative, for sorption of perfluorooctanesulfonate (PFOS) in the presence of magnesium ions (Mg 2þ ), owing to the ability of Mg 2þ to form a bridge between PFOS and GO (Zhao et al 2016). Similar demonstrations for PFOA and other PFASs are not available.…”

“…The most common PFASs of concern, including PFOA and PFOS, exist as anions, which can be repelled by negatively-charged adsorbents. It is thus reasonable to assume that despite avenues for hydrophobic or bridging interactions (Zhao et al 2016), GO is not the best candidate for PFAS sorption, and other GBMs may provide opportunities for superior binding. Graphene oxide is remarkably amenable to surface modifications, owing to its oxygen functionalities, and can be strategically functionalised for enhanced contaminant sorption.…”

Superhydrophobic and oleophilic micro‐nano hierarchical Pd‐decorated SiO2 layers

“…Figure B shows an XPS survey of the Pd‐SiO 2 /PFOS layer. As shown in Figure B‐1, C 1s core level can be deconveloted to 4 peaks, C‐C (284.78 eV), C‐O (287.18 eV), CF 2 (293.98 eV), and CF 3 (291.48 eV), where the last 2 peaks show the bonding of carbon with fluorine ions in PFOS. Si 2p core level is shown in Figure B‐2, where a strong peak related to SiO 2 is observed.…”

A review on application of graphene‐based microfluidics

“…Zhao et al presented microfluidics‐generated GO microspheres and their application to removal of perfluorooctane sulfonate from polluted water. This novel material was a potential solution for treatment of bioaccumulative organic polluted water . Bao et al immobilized trypsin in the layer‐by‐layer coating of GO and chitosan on a piece of glass fiber to fabricate microchip bioreactor for efficient proteolysis; Fig.…”