Performance of Carbon Nanotube/Polysulfone (CNT/Psf) Composite Membranes during Oil-Water Mixture Separation: Effect of CNT Dispersion Method.

Michael Daramola,Olugbenga Oluwasina,Palesa Hlanyane,Sunny Iyuke,Oluwafolakemi Sadare

doi:10.3390/membranes7010014

Michael Daramola, Olugbenga Oluwasina + Show 3 more

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https://doi.org/10.3390/membranes7010014

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Abstract

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.

Highlights

Application of mixed matrix membranes (MMMs) in wastewater treatment is gaining interest amongst researchers due to the enhanced mechanical strength, permeability, and selectivity of these membranes when compared to those of equivalent pure polymeric membranes [1]
The results obtained in this study indicate the carbon nanotube (CNT)/Psf membranes will be less prone to fouling when compared to the pure Psf membranes
Morphology and the surface functionality of the membranes were checked with scanning electron microscopy (SEM) and Fourier-transformation infrared (FTIR), respectively

Summary

Introduction

Application of mixed matrix membranes (MMMs) in wastewater treatment is gaining interest amongst researchers due to the enhanced mechanical strength, permeability, and selectivity of these membranes when compared to those of equivalent pure polymeric membranes [1]. MMMs are prepared by dispersing porous particles, such as zeolites [2], carbon molecular sieves [3], silica [4], and carbon nanotubes (CNTs) [5,6] within the polymer matrix of polymers such as polysulfone, polyether sulfone, and polyamide [1]. The membranes were prepared via phase inversion technique by blending silica and bentonite nanoparticles separately with polysulfone and N-methyl-2-pyrrolidone solution. The result of effects of silica- and bentonite-loading on pure water flux at different transmembrane pressure (TMP) (100–300 kPa) at an increment of 50 kPa for pure water flux for membrane Psf (pure without nanoparticles), Psf/silica-3 (containing 3 wt % silica), Psf/silica-8 The permeability recorded for these membranes were 0.97 × 1010 m·Pa−1 ·s−1 (for Psf), 1.53 × 1010 m·Pa−1 ·s−1

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