Impact of Carbon Nanotubes on the Polymeric Membrane for Oil – Water Separation (original) (raw)
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Membranes, 2017
Effect of the dispersion method employed during the synthesis of carbon nanotube (CNT)/polysulfone-infused composite membranes on the quality and separation performance of the membranes during oil-water mixture separation is demonstrated. Carbon nanotube/polysulfone composite membranes containing 5% CNT and pure polysulfone membrane (with 0% CNT) were synthesized using phase inversion. Three CNT dispersion methods referred to as Method 1 (M1), Method 2 (M2), and Method 3 (M3) were used to disperse the CNTs. Morphology and surface property of the synthesized membranes were checked with scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy, respectively. Separation performance of the membranes was evaluated by applying the membrane to the separation of oil-water emulsion using a cross-flow filtration setup. The functional groups obtained from the FTIR spectra for the membranes and the CNTs included carboxylic acid groups (O-H) and carbonyl group (C=O) which are responsible for the hydrophilic properties of the membranes. The contact angles for the membranes obtained from Method 1, Method 2, and Method 3 were 76.6 • ± 5.0 • , 77.9 • ± 1.3 • , and 77.3 • ± 4.5 • , respectively, and 88.1 • ± 2.1 • was obtained for the pure polysulfone membrane. The oil rejection (OR) for the synthesized composite membranes from Method 1, Method 2, and Method 3 were 48.71%, 65.86%, and 99.88%, respectively, indicating that Method 3 resulted in membrane of the best quality and separation performance. Membranes 2017, 7, 14 2 of 15
Scientific reports, 2013
A carbon nanotube (CNT) integrated polymer composite membrane with a polyvinyl alcohol barrier layer has been prepared to separate oil from water for treatment of oil-containing waste water. The CNTs were synthesised using chemical vapour deposition, and a phase inversion method was employed for the blending of the CNTs in the polymer composite solution for casting of the membrane. Relative to the baseline polymer, an increase of 119% in the tensile strength, 77% in the Young's modulus and 258% in the toughness is seen for a concentration of 7.5% CNTs in the polymer composite. The permeate through the membrane shows oil concentrations below the acceptable 10 mg/L limit with an excellent throughput and oil rejection of over 95%.
Investigation of Carbon Nanotubes in Mixed Matrix Membranes for Gas Separation: A Review
ChemBioEng Reviews, 2016
Mixed matrix membranes (MMM) consist of a polymeric base with additive fillers. Zeolites, carbon molecular sieves, graphene and carbon nanotubes (CNTs) are most commonly used fillers in the development of MMMs. Among these materials, CNTs have been proposed recently for gas separation application due to their attractive properties. Although CNTs have excellent separation properties, preparation of CNT-MMMs is more complicated. To employ CNTs as effective reinforcement in the polymeric matrix, proper dispersion and suitable interfacial adhesion between the CNTs and the polymer matrix have to be guaranteed. In this paper, recent advances and developments on CNTs dispersion and alignment in the matrix were reviewed. Also, a critical comparison of various CNT functionalization methods and different functional groups are given. Applications of CNT-MMMs in gas separation are also reviewed.
Separation of oil/water emulsion using a new PSf/pebax/F-MWCNT nanocomposite membrane
Journal of the Taiwan Institute of Chemical Engineers, 2017
In this study a new PSf/pebax/F-MWCNTs nanocomposite membrane was prepared, characterized and used for nanofiltration of oil/water emulsion. For this purpose, the porous PSf support was prepared and then a thin layer of pebax as selective layer was coated on it. The effect of adding 0.5, 1 and 2 wt% of functionalized multiwall carbon nanotubes (F-MWCNTs) on the morphology and separation properties of resulting membranes were studied systematically. Prepared membranes were analyzed using SEM, FTIR, contact angel, tensile strength and TGA analyses. FTIR results approved the stabilization of F-MWCNTs in membrane matrix. SEM showed the membrane surface was defect free and F-MWCNTs particles were not agglomerated. Increasing F-MWCNT up to 2 wt%, increased hydrophilicity, tensile strength and thermal stability. Separation of oil/water emulsion was investigated at pressure range of 10-20 bar The highest permeate flux was obtained for 0.5 wt% F-MWCNTs loading while the sample containing 2.0 wt% F-MWCNTs showed the best oil rejection at all studied pressures. Results revealed that oil rejection was decreased with pressure. Finally, flux recovery, irreversible and reversible fouling was analyzed for all the prepared membranes at all pressures.
Journal of Applied Polymer Science, 2016
The development of desirable chemical structures and properties in nanocomposite membranes involve steps that need to be carefully designed and controlled. This study investigates the effect of adding multiwalled nanotubes (MWNT) on a Kapton-polysulfone composite membrane on the separation of various gas pairs. Data from Fourier transform infrared spectroscopy and scanning electron microscopy confirm that some studies on the Kapton-polysulfone blends are miscible on the molecular level. In fact, the results indicate that the chemical structure of the blend components, the Kapton-polysulfone blend compositions, and the carbon nanotubes play important roles in the transport properties of the resulting membranes. The results of gas permeability tests for the synthesized membranes specify that using a higher percentage of polysulfone (PSF) in blends resulted in membranes with higher ideal selectivity and permeability. Although the addition of nanotubes can increase the permeability of gases, it decreases gas pair selectivity. Furthermore, these outcomes suggest that Kapton-PSF membranes with higher PSF are special candidates for CO 2 /CH 4 separation compared to CO 2 /N 2 and O 2 /N 2 separation. High CH 4 , CO 2 , N 2 , and O 2 permeabilities of 0.35, 6.2, 0.34, and 1.15 bar, respectively, are obtained for the developed Kapton-PSF membranes (25/75%) with the highest percentage of carbon nanotubes (8%), whose values are the highest among all the resultant membranes.
Nanoscale Research Letters, 2012
The present work reports on the gas transport behavior of mixed matrix membranes (MMM) which were prepared from multi-walled carbon nanotubes (MWCNTs) and dispersed within polymers of intrinsic microporosity (PIM)-1 matrix. The MWCNTs were chemically functionalized with poly(ethylene glycol) (PEG) for a better dispersion in the polymer matrix. MMM-incorporating functionalized MWCNTs (f-MWCNTs) were fabricated by dip-coating method using microporous polyacrylonitrile membrane as a support and were characterized for gas separation performance. Gas permeation measurements show that MMM incorporated with pristine or functionalized MWCNTs exhibited improved gas separation performance compared to pure PIM-1. The f-MWCNTs MMM show better performance in terms of permeance and selectivity in comparison to pristine MWCNTs. The gas permeances of the derived MMM are increased to approximately 50% without sacrificing the selectivity at 2 wt.% of f-MWCNTs' loading. The PEG groups on the MWCNTs have strong interaction with CO 2 which increases the solubility of polar gas and limit the solubility of nonpolar gas, which is advantageous for CO 2 /N 2 selectivity. The addition of f-MWCNTs inside the polymer matrix also improved the long-term gas transport stability of MMM in comparison with PIM-1. The high permeance, selectivity, and long term stability of the fabricated MMM suggest that the reported approach can be utilized in practical gas separation technology.
Journal of Applied Polymer Science, 1999
Asymmetric polysulfone membranes were prepared by the phase inversion technique under different solvent evaporation conditions prior to the gelation step. The membranes were cast from the two component system of polymer and N,N-dimethylacetamide in which the polymer concentration was changed from 25.0 to 30.0%. The solvent evaporation temperature was changed from 70 to 120°C, and the evaporation time was 0 -15 min. Ethanol, water, or 2-propanol was used as the gelation media. The membranes were characterized by the measurement of oxygen/nitrogen permeation with the lamination technique and by observation with scanning electron microscopy. With an increase in the solvent evaporation time, the oxygen permeance decreased and its selectivity over nitrogen increased; although the permeance was in the range of 1-2 GPU, the oxygen selectivity over nitrogen exceeded 8. A correlation between the permeation performance and the operational parameters involved in the solvent evaporation process was obtained.
Polymers
Nowadays, reverse osmosis is the most widely utilized strategy in membrane technology due to its continuous improvement. Recent studies have highlighted the importance of the surface characteristics of support layers in thin-film membranes to improve their reverse osmosis performance. In this study, interfacial polymerization was used to generate the membranes by employing polyamide as a selective layer on top of the polysulfone supporting sheet. Different membranes, varying in terms of the concentrations of unfunctionalized and functionalized multiwalled carbon nanotubes (MWCNTs), as well as ethanol, have been fabricated. The efficiency of the membrane has been increased by increasing its permeability towards water with high salt rejection. Different characterization techniques were applied to examine all of the fabricated membranes. PA-EtOH 30% (v/v), as a selective layer on polysulfone sheets to enhance the membrane’s salt rejection, was shown to be the most efficient of the sugg...
Separations, 2020
Poly(ethylene-co-vinylalcohol) (E-VOH) and carbon nanotube-filled poly (vinyl alcohol-co-ethylene) (E-VOH/CNT) were used as membranes to separate benzene/cyclohexane mixtures by pervaporation technique. To reach this goal, E-VOH and E-VOH/CNT membranes were prepared by solvent casting method and characterized by differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The swelling tests were used to study the mass transfer of the benzene/cyclohexane mixture and their pure components. The separation by pervaporation process was carried out at 25 °C in which the effect of CNTs incorporated into E-VOH matrix and the initial concentration of benzene in the feed on the permeate flux, j, and separation factor, β, performance was investigated. The results obtained were very promising, in which the integration of CNTs through E-VOH chains increased the absorption area and raised the flux to 740 g/m2∙h. The sep...