Reinforcement of nanostructured reduced graphene oxide: a facile approach to develop high-performance nanocomposite ultrafiltration membranes minimizing the trade-off between flux and selectivity

Abstract

The salient features of a nanostructured carbonaceous material like graphene or graphene oxide have provided innovative alternatives for the development of nanocomposite membranes with better selectivity without having a compromise in throughput, which as a result have a promising role to play in desalination and water purification. Here, nanostructured reduced graphene oxide (nRGO) is synthesized from graphite powder and characterized. Using non-solvent induced phase inversion technique, a series of nanocomposite ultrafiltration (UF) membranes are developed by in situ impregnation of the as synthesized nRGO in polysulfone (Ps) polymer matrix with variation of nRGO from 1 to 8 w/w%. The physicochemical features and transport properties offered by the membranes are evaluated. Structural characterization of the Ps-nRGO composite UF membranes is done by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The variation in porous morphology of the membranes upon impregnation of nRGO is evaluated by scanning electron microscopy. Variation in skin surface topography is analyzed by atomic force microscopy. The change in surface hydrophilicity is evaluated by contact angle studies. The thermal and mechanical properties of the membranes are assessed by thermogravimetric analysis and tensile strength measurements, respectively. The studies reveal that an optimum loading of nRGO (2 w/w%) in the Ps matrix resulted in membranes with elimination of the trade-off between the flux and selectivity that exists with the conventional UF membranes. In addition, the optimum loading of nRGO resulted in membranes with improved thermal and mechanical stability. Thus, nRGO as an emerging potential nanofiller can lead to the development of an ideal membrane with desirable attributes.

Mixed-matrix membranes with enhanced antifouling activity: probing the surface-tailoring potential of Tiron and chromotropic acid for nano-TiO 2

“…The improvement in the hydrophilic nature corroborates the presence of hydrophilic groups of the tethered organoligands, which could significantly enhance the efficacy of nano-TiO 2 in modifying the intrinsic hydrophobic nature of the Control-Psf UF. The facilitated distribution of organofunctionalized nano-TiO 2 within the Psf matrix implies that the modified nanoadditives not only influence the physico-chemical features of the membrane skin surface but also the skin layer porous pathways [ 53 ], which collectively contribute towards enhancing the hydrophilicity of the MMMs.

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Enhanced both water flux and salt rejection of reverse osmosis membrane through combining isophthaloyl dichloride with biphenyl tetraacyl chloride as organic phase monomer for seawater desalination

“…Compared with MPDA, the cross-linked degree of PA TFC membrane reduces led to water flux increase with a slight decrease in salt rejection. But because the "trade-off" phenomenon [25] exits in the transport process, most studies improve the water flux through decreasing the rigidity and chain cross-linked degree with sacrificing salt rejection or improve the salt rejection with water flux decrease. Therefore, how to keep high salt rejection with excellent water flux is a question deserving to study further.…”

Sustainable Jatropha Oil-Based Membrane with Graphene Oxide for Potential Application in Cu(II) Ion Removal from Aqueous Solution

“…The thermal stabilities of the JPU/GO samples increased and were compatible with the decomposition temperature of TGA thermograms. As reported by Avishek et al [66], the uniform distribution of the nanofillers within the polymer had caused the increment of thermal stability due to the restraining of the flexibility and mobility of the polymer chains. Results from TGA provided the degradation peaks versus temperature with residue weight of the JPU membrane.…”

“…The amphiphilic nature of GO had formed water channel as water molecules were first absorbed onto the hydrophilic sites to allow water diffusion onto the hydrophobic carbon sites [84,90]. Similarly, in the case of polysulfone-nanostructured reduced graphene oxide (Ps-nRGO) composite UF membrane, loading of nRGO in Ps matrix had formed automatically smooth interconnected interlayer that caused higher water flux in Ps-nRGO than pristine Ps NF membrane [66].…”

“…Processes 2020, 8, x FOR PEER REVIEW 17 of 22 amphiphilic nature of GO had formed water channel as water molecules were first absorbed onto the hydrophilic sites to allow water diffusion onto the hydrophobic carbon sites [84,90]. Similarly, in the case of polysulfone-nanostructured reduced graphene oxide (Ps-nRGO) composite UF membrane, loading of nRGO in Ps matrix had formed automatically smooth interconnected interlayer that caused higher water flux in Ps-nRGO than pristine Ps NF membrane [66]. However, as loading of GO in JPU matrix increased to 0.65 wt%, water flux decreased to 260 L/m 2 .h, which is almost similar to pristine JPU at 223.33 L/m 2 h. In contrast to JPU/GO samples with 0.35 wt% and 0.50 wt% GO loading in JPU matrix, higher water flux was recorded at 406.66 L/m 2 .h and 523.33 L/m 2 .h, respectively.…”