Improved sorption of perfluorooctanoic acid on carbon nanotubes hybridized by metal oxide nanoparticles
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Multi-walled carbon nanotubes (MWCNTs) are often used as adsorbent because of their strong adsorption capacity. However, due to the nature of MWCNTs, their ability to adsorb perfluorooctanoic acid (PFOA), a highly hydrophobic pollutant, is low. In this study, MWCNTs were modified by three nano metal oxides (nano iron oxide, copper oxide, and zinc oxide). The pristine (as the control) and modified MWCNTs were characterized by BET-N2, TEM, FTIR, XPS, and XRD, which showed that nano metal oxides were well hybridized on the surface of MWCNTs. Radioactive-labeled PFOA (14C-PFOA) was used to quantify it at trace level. Adsorption kinetics showed that intra-particle diffusion was the control step of PFOA adsorbing on metal oxides hybridized MWCNTs (MOHCNTs). Adsorption capacity of PFOA on the MOHCNTs was higher than that on the control due to electrostatic and hydrophobic interactions. In addition, PFOA formed inner-sphere complexes with metal oxide nanoparticles via ligand exchange. The alteration of PFOA adsorption capacity by increasing ionic strength was attributed to the aggregation degree of MWCNTs, electrostatic shielding, and/or salting out effect. The presence of Ca2+ increased the adsorption, owing to not only its higher electrostatic shielding ability than Na+ but also its formation of bridge between PFOA and MOHCNTs. PFOA adsorption on MOHCNTs strongly depended on medium pH value. These results provide an innovative approach for removing trace PFOA from liquid medium.
KeywordsMetal oxide nanoparticles Hybridized Carbon nanotubes Sorption PFOA
This work was financially supported by the National Nature Science Foundation of China (Project No. 21377074) and Collaborative Fund between National Nature Science Foundation of China and Swiss National Science Foundation (Project No. 21661132004). We also thanked Dr. Bin Gao, Florida University to improve English in the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bard AJ, Faulkner LR (2001) Electrochemical methods fundamentals and applications, 2nd ed. Wiley, Hoboken. Chapter 4, pp 140–146Google Scholar
- Ghaedi M, Shokrollahi A, Hossainian H, Kokhdan SN (2011a) Comparison of activated carbon and multiwalled carbon nanotubes for efficient removal of eriochrome cyanine R (ECR): kinetic, isotherm, and thermodynamic study of the removal process. J Chem Eng Data 56:3227–3235. https://doi.org/10.1021/je200331u CrossRefGoogle Scholar
- Hosseini SJ, Kokhdan SN, Ghaedi AM, Moosavian SS (2011) Comparison of multiwalled carbon nanotubes and activated carbon for efficient removal of methyl orange: kinetic and thermodynamic investigation. Fresenius Environ Bull 20:219–234Google Scholar
- Jusoh NWC, Jalil AA, Triwahyono S, Setiabudi HD, Sapawe N, Satar MAH, Karim AH, Kamarudin NHN, Jusoh R, Jaafar NF, Salamun N, Efendi J (2013) Sequential desilication–isomorphous substitution route to prepare mesostructured silica nanoparticles loaded with ZnO and their photocatalytic activity. Appl Catal A 468:276–287. https://doi.org/10.1016/j.apcata.2013.09.005 CrossRefGoogle Scholar
- Li CL, Schäffer A, Séquaris JM, László K, Tóth A, Tombácz E, Vereecken H, Ji R, Klumpp E (2012) Surface-associated metal catalyst enhances the sorption of perfluorooctanoic acid to multi-walled carbon nanotubes. J Colloid Interface Sci 377:342–346. https://doi.org/10.1016/j.jcis.2012.03.038 CrossRefGoogle Scholar
- Liu ZY, Lu YL, Wang TY, Wang P, Li QF, Johnson AC, Sarvajayakesavalu S, Sweetman AJ (2016) Risk assessment and source identification of perfluoroalkyl acids in surface and ground water: spatial distribution around a mega-fluorochemical industrial park, China. Environ Int 91:69–77. https://doi.org/10.1016/j.envint.2016.02.020 CrossRefGoogle Scholar
- Liu D, Du PC, Wei WL, Wang HX, Wang Q, Liu P (2017b) Flexible and robust sandwich-structured S-doped reduced graphene oxide/carbon nanotubes/polyaniline (S-rGO/CNTs/PANI) composite membranes: excellent candidate as free-standing electrodes for high-performance supercapacitors. Electrochim Acta 233:201–209. https://doi.org/10.1016/j.electacta.2017.03.040 CrossRefGoogle Scholar
- Pramanika BK, Pramanikb SK, Suja F (2015) A comparative study of coagulation, granular- and powdered-activated carbon for the removal of perfluorooctane sulfonate and perfluorooctanoate in drinking water treatment. Environ Technol 36:2610–2617. https://doi.org/10.1080/09593330.2015.1040079 CrossRefGoogle Scholar
- Thompson J, Eaglesham G, Reungoat J, Poussade Y, Bartkow M, Lawrence M, Mueller JF (2011) Removal of PFOS, PFOA and other perfluoroalkyl acids at water reclamation plants in south East Queensland Australia. Chemosphere 82:9–17. https://doi.org/10.1016/j.chemosphere.2010.10.040 CrossRefGoogle Scholar
- Yang LZ, Xu Y, Wang XH, Zhu J, Zhang RY, He PG, Fang YZ (2011) The application of β-cyclodextrin derivative functionalized aligned carbon nanotubes for electrochemically DNA sensing via host-guest recognition. Anal Chim Acta 689:39–46. https://doi.org/10.1016/j.aca.2011.01.026 CrossRefGoogle Scholar