Capture of Perfluorooctanoic Acid Using Oil-Filled Graphene Oxide–Silica Hybrid Capsules (original) (raw)
Related papers
Environmental Chemistry, 2018
Environmental contextPer- and poly-fluoroalkyl substances (PFASs) are contaminants of emerging concern, creating a need to develop efficient multi-functional adsorbents for improved remediation performance. By exploiting the versatility of graphene technology, we demonstrate that combining mineral and carbonaceous phases greatly increases and strengthens PFAS-binding to the adsorbent. The study highlights the benefits and potential applications of mixed adsorbents in PFAS-remediation. As the degradation of perfluorooctanoic acid (PFOA) and related per- and poly-fluoroalkyl substances (PFASs) is energy-intensive, there is a need to develop in situ remediation strategies to manage PFAS-contamination. The sorption of PFOA by graphene oxide (GO), an iron-oxide-modified reduced-GO composite (FeG) and an activated-carbon(C)/clay/alumina-based adsorbent, RemBindTM (RemB), are evaluated. Sorption by FeG and RemB (>90%) is much greater than GO (60%). While an increase in pH hinders PFOA-s...
Applied Water Science
Perfluorooctane sulfonic acid (PFOS), a perfluoroalkyl substance, has engendered alarm over its presence in water sources due to its intrinsic toxicity. Hence, there is a pressing need to identify efficacious adsorbents capable of removing PFAS derivatives from water. To achieve this, batch adsorption studies under various circumstances were employed to tune amorphous polymer networks regarding their morphological configuration, heat durability, surface area and capacity to adsorb PFOS in water. A facile, one-pot nucleophilic substitution reaction was employed to synthesize amorphous polymer networks using triazine derivatives as building units for monomers. Notably, POP-3 exhibited a superlative adsorption capacity, with a removal efficiency of 97.8%, compared to 90.3% for POP-7. POP-7 exhibited a higher specific surface area (SBET) of 232 m2 g−1 compared to POP-3 with a surface area of 5.2 m2 g−1. Additionally, the study emphasizes the importance of electrostatic forces in PFOS ad...
ACS Omega
Per-and poly-fluoroalkyl substances (PFASs) are man-made chemicals that are toxic and widely detected in the environment, including drinking water sources. A costeffective treatment process for PFASs is currently not available. We developed reusable hydrogel sorbents to remove long-and short-chain perfluoroalkyl acids and 2,3,3,3tetrafluoro-2-(heptafluoropropoxy)propanoic acid (GenX), which is are emerging PFAS. Through fluoridation and amination of poly(ethylene glycol) diacrylate (PEGDA), the newly synthesized sorbents can sorb the five targeted PFASs (perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorobutanesulfonic acid (PFBS), and perfluorobutanoic acid (PFBA) and GenX) to different degrees from aqueous solution. Aminated PEGDA showed the highest sorption capacity for all five PFASs, particularly for PFBA and PFBS. The bifunctionalized PEGDA showed higher capacities for PFOA and PFOS, suggesting that both hydrophobic interactions and charges contribute to the sorption. Both aminated and bifunctionalized sorbents can remove GenX from water, with the highest sorption capacity of 98.7 μmol g aminated PEGDA −1 within 6 h. The absorbed PFASs on the sorbents were observed and characterized by Fourier-transform infrared spectroscopy. The spent sorbents were reusable after readily regenerated with 70% methanol contained 1% NaCl.
Photocatalytic degradation of perfluorooctanoic acid with β-Ga2O3 in anoxic aqueous solution
Journal of Environmental Sciences, 2012
Perfluorooctanoic acid (PFOA, C 7 F 15 COOH) has been recently classified as an emerging persistent organic pollutant (POP) by the United States Environmental Protection Agency (U.S. EPA) [1]. It has been proposed for restriction in the European Chemicals Agency (ECHA) [2] and in October 2015, it has been submitted by the European Union to the Stockholm convention to be included in the list of POP's [3]. It belongs to the class of fully fluorinated hydrocarbons also known as perfluorcarboxylic acids (PFCAs, C n F 2n+1 COOH). PFCA's contain a characteristic carboxylic group at the terminal end of the chain of perfluorinated carbon atoms with varying length that are derived from hydrocarbons by replacing the hydrogen atoms with fluorine atoms [4, 5]. The carbon-fluorine bonds present in these molecules are very strong making PFOA extremely hydrophobic, lipophobic, as well as thermally and chemically stable with an active surface [6, 7]. Due to this characteristics PFOA has been widely utilized in industrial and commercial applications in the past six decades ranging from coatings for clothing, leather and carpets that are water, soil and stain resistant; oil resistant coatings for food packages; aviation hydraulic fluids; fire retardants (fire-fighting foams) until industrial utilization as surfactants; emulsifiers; wetting agents; additives and coatings for production of polytetrafluorethylene (PTFE) and others [8-12]. The same characteristics that makes it an important industrial and commercial constituent also makes PFOA a strong bioaccumulative and persistent compound and therefore it has often been found in the environment around the world, mainly in the water matrix, such as finished drinking water, surface water and groundwater, but also in sludge, soils, sediments, outdoor and indoor dust, polar ice caps and recently also in living organisms [8, 13-15].
Synthesis of a Fluorinated Graphene Oxide-Silica Nanohybrid: Improving Oxygen Affinity
An easy method to achieve a fluorinated graphene oxide-silica nanohybrid (GOSF) is presented. Graphene oxide (GO) was synthesized by Hummers modified method, the GO-silica nanohybrid (GOS) was obtained via Fischer esterification, the fluorinated moiety (3-pentadecafluoroheptyl,5-perfluorophenyl-1,2,4-oxadiazole) was introduced by nucleophilic substitution operated by the hydroxyl functionalities onto the GOS surface. Full characterization of the new materials confirmed the formation of covalent bonds between the graphene oxide /silica hybrid matrix and the fluorinated moieties. The proposed methodology offers an easy way to get fluorinated carbon/silica hybrid nanomaterials avoiding the harsh reaction conditions usually involved in the preparation of fluorinated materials, and allowing to selectively immobilize specific fluorotails. Moreover, performed oxygen uptake and release kinetics showed that the introduction of fluorinated moieties increases the oxygen exchange, making the material interesting for perspective applications in biomedical field, as oxygen delivery system, as filler for biocompatible materials, and in the preparation of membranes for purification of water.
Environmental Science & Technology, 2018
We demonstrate the fabrication of a loose, negatively charged nanofiltration (NF) membrane with tailored selectivity for the removal of perfluoroalkyl substances with reduced scaling potential. A selective polyamide layer was fabricated on top of a poly(ether sulfone) support via interfacial polymerization of trimesoyl chloride and a mixture of piperazine and bipiperidine. Incorporating high molecular weight bipiperidine during the interfacial polymerization enables the formation of a loose, nanoporous selective layer structure. The fabricated NF membrane possessed a negative surface charge and had a pore diameter of ∼1.2 nm, much larger than a widely used commercial NF membrane (i.e., NF270 with pore diameter of ∼0.8 nm). We evaluated the performance of the fabricated NF membrane for the rejection of different salts (i.e., NaCl, CaCl 2 , and Na 2 SO 4) and perfluorooctanoic acid (PFOA). The fabricated NF membrane exhibited a high retention of PFOA (∼90%) while allowing high passage of scale-forming cations (i.e., calcium). We further performed gypsum scaling experiments to demonstrate lower scaling potential of the fabricated loose porous NF membrane compared to NF membranes having a dense selective layer under solution conditions simulating high water recovery. Our results demonstrate that properly designed NF membranes are a critical component of a high recovery NF system, which provide an efficient and sustainable solution for remediation of groundwater contaminated with perfluoroalkyl substances.
Alternative Fluoropolymers to Avoid the Challenges Associated with Perfluorooctanoic Acid
Industrial & Engineering Chemistry Research, 2008
The degradation of stain-resistant coating materials leads to the release of biopersistent perfluorooctanoic acid (PFOA) to the environment. In order to find the environmentally friendly substitutes, we have designed and synthesized a series of nonbiopersistant fluorinated polymers containing perfluorobutyl groups in the side chains. The surface properties of the new coating materials were characterized by static and dynamic contact angle
Journal of Membrane Science, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.