Effect of Loading and Functionalization of Carbon Nanotube on the Performance of Blended Polysulfone/Polyethersulfone Membrane during Treatment of Wastewater Containing Phenol and Benzene

Abstract

In this study, a carbon nanotube (CNT)-infused blended polymer membrane was prepared and evaluated for phenol and benzene removal from petroleum industry wastewater. A 25:75 (by weight %) blended polysulfone/polyethersulfone (PSF/PES) membrane infused with CNTs was prepared and tested. The effect of functionalization of the CNTs on the quality and performance of the membrane was also investigated. The membranes were loaded with CNTs at different loadings: 0.5 wt. %, 1 wt. %, 1.5 wt. % pure CNTs (pCNTs) and 1 wt. % functionalized CNTs (fCNTs), to gain an insight into the effect of the amount of CNT on the quality and performance of the membranes. Physicochemical properties of the as-prepared membranes were obtained using scanning electron microscopy (SEM) for morphology, Raman spectroscopy for purity of the CNTs, Fourier transform infrared (FTIR) for surface chemistry, thermogravimetric analysis (TGA) for thermal stability, atomic force microscopy (AFM) for surface nature and nano-tensile analysis for the mechanical strength of the membranes. The performance of the membrane was tested with synthetic wastewater containing 20 ppm of phenol and 20 ppm of benzene using a dead-end filtration cell at a pressure ranging from 100 to 300 kPa. The results show that embedding CNTs in the blended polymer (PSF/PES) increased both the porosity and water absorption capacity of the membranes, thereby resulting in enhanced water flux up to 309 L/m2h for 1.5 wt. % pCNTs and 326 L/m2h for 1 wt. % functionalized CNT-loaded membrane. Infusing the polysulfone/polyethersulfone (PSF/PES) membrane with CNTs enhanced the thermal stability and mechanical strength. Results from AFM indicate enhanced hydrophilicity of the membranes, translating in the enhancement of anti-fouling properties of the membranes. However, the % rejection of membranes with CNTs decreased with an increase in pCNTs concentration and pressure, while it increased the membrane with fCNTs. The % rejection of benzene in the pCNTs membrane decreased with 13.5% and 7.55% in fCNT membrane while phenol decreased with 55.6% in pCNT membrane and 42.9% in the FCNT membrane. This can be attributed to poor CNT dispersion resulting in increased pore sizes observed when CNT concentration increases. Optimization of membrane synthesis might be required to enhance the separation performance of the membranes.

Effect of Silica Sodalite Functionalization and PVA Coating on Performance of Sodalite Infused PSF Membrane during Treatment of Acid Mine Drainage

“…There is no visible separate layers on the 10% fSSOD/Psf/PVA membrane as shown in Figure 6 c. This shows that there was a good bond formation between the Psf and PVA layers. The results obtained in this study are consistent with what was obtained in the literature [ 38 , 39 ].…”

“…Figure 6 a shows the 10% SSOD/Psf membrane with an area marked A showing agglomeration of nanoparticles on the cross sectional area of the membranes. This has been shown to limit membrane performance due to the increased free void volume [ 38 ]. The 10% fSSOD/Psf membrane in Figure 6 b shows an improved distribution of nanoparticles on the membrane surface.…”

“…The fSSOD-loaded membranes show increased surface roughness when compared to the SSOD-loaded membranes (see Figure 9 ). This was not expected because the infusion of functionalized nanoparticles should reduce the surface roughness of the membrane because of the added carboxylic acid groups on the nanoparticles surface that can reduce the deposition of foulants on the surface of the membrane [ 38 ]. The unexpected reduction in surface roughness of the 10% SSOD/Psf membrane could be attributed to the ineffective dispersion of nanoparticles within the membrane.…”

“…A general trend of increasing pure water flux at increasing pressure was observed for all the membranes (see Figure 10 ). This can be attributed to the increased driving force that facilitated the enhancement of the capillary pressure of the membrane resulting in enhanced water permeation through the membranes [ 38 ]. The infusion of nanoparticles has improved the permeability of the membranes.…”

Hollow fibre membrane bioreactor functionalized with GO‐cryogel 3D matrix promotes liver cell anchoring and their functional maintenance

“…Moreover, it may be noted that functionalized multi‐walled carbon nanotubes (CNTs) as fillers in polymer membranes to improve the biocompatibility and separation performance has also gained the attention as discussed in the literature (Abidin et al, 2017; Kaleekkal et al, 2016; Saliev, 2019; Tan et al, 2014). Apart from biocompatibility improvement, CNTs also help in enhancing the mechanical and separation properties of the biomaterials (Cao et al, 2020; Feng et al, 2015; Manawi et al, 2018; Rameetse et al, 2020).…”