Separation of Emulsified Oil from Oily Wastewater by Functionalized Multiwalled Carbon Nanotubes |
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Authors: | Juan Liu Xiaocheng Li Weihong Jia Mingshan Ding Yan Zhang |
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Institution: | 1. State Key laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, P. R. China;2. University of Chinese Academy of Sciences, Beijing, P. R. China;3. Laboratory of Clean Energy Chemistry and Materials, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, P. R. China |
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Abstract: | Rapid separation of emulsified oil from oily wastewater is one of the most serious challenges faced in the petroleum industry. In this study, a rapid and efficient demulsifier, functionalized multiwalled carbon nanotubes (F-MWCNTs), was prepared and used to separate the emulsified oil from oily wastewater. Demulsification test showed that the oil removal efficiency could attain as high as 99.8% at an optimal condition within a few minutes. The micro-morphology of the oil–water mixture before and after demulsification was observed using a polarizing microscope. It was found that the fine oil droplets experienced a rapid coalescence to form oil phase floating on the water surface. Mechanism of the demulsification process was discussed. The introduction of the functional groups (such as ?OH and ?COOH) on the surfaces of F-MWCNTs enable them good amphiphilicity and therefore easily arriving at the oil/water interface to destroy the interfacial protective film mainly composed of asphaltenes and resins. The findings in this work showed that the F-MWCNT is an efficient nanomaterial to remove emulsified oil from the oily wastewater and might have wide application prospects in the petroleum industry. |
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Keywords: | Crude oil-in-water emulsion demulsification multiwalled carbon nanotubes oil/water separation |
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