Modification of polyethersulfone with partially reduced graphene oxide and its water purification application

Nanofiltration is mostly used to treat surface water and wastewater to remove contaminants like heavy metals, small organics, calcium, magnesium and reduce the water hardness. Enhancing membrane properties such as surface characteristics and pore structure can lead to improved separation performance...

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Main Authors: Teboho R. Motlokoa, Winny K. Maboya, Charity Mbileni-Morema, Sekomeng J. Modise, Bamidele J. Okoli
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Desalination and Water Treatment
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Online Access:http://www.sciencedirect.com/science/article/pii/S1944398625003571
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author Teboho R. Motlokoa
Winny K. Maboya
Charity Mbileni-Morema
Sekomeng J. Modise
Bamidele J. Okoli
author_facet Teboho R. Motlokoa
Winny K. Maboya
Charity Mbileni-Morema
Sekomeng J. Modise
Bamidele J. Okoli
author_sort Teboho R. Motlokoa
collection DOAJ
description Nanofiltration is mostly used to treat surface water and wastewater to remove contaminants like heavy metals, small organics, calcium, magnesium and reduce the water hardness. Enhancing membrane properties such as surface characteristics and pore structure can lead to improved separation performance, greater wettability, and a longer lifespan. The study introduces a novel approach for enhancing magnesium ion rejection using a polyether sulphone (PES) membrane embedded with a nanocomposite of partially reduced graphene oxide (rGO). The effect of varying concentration of rGO nanocomposite ranging from 1 to 5 wt% in the fabricated membrane was evaluated in terms of pure water permeation, salt rejection, morphology, and hydrophilicity. EDX analysis of rGO confirmed its partial reduction, evidenced by a decrease in oxygen content from 34.8 % to 27.6 %. The composite membrane demonstrates that incorporating PES and partially rGO improved the wettability, water flux and effective solute rejection due to reduction of the hydrophilic groups. PES with 5 wt% of rGO nanocomposite obtained the highest PWP at 38 L/m2h, whereas the highest rejections of monovalent and divalent salts were obtained by PES with 1 wt% rGO with 77 %, 81 % and 87 % salt rejections for Mg2 + , Na+ and Ca2+, respectively and with the PWP of 30 L/m2h. The decline in salt rejections at higher rGO concentrations suggests that aggregation and increased viscosity inhibited free space formation, negatively affecting permeability. The study shows that partial reduction of GO and its utilization as an additive in the PES casting solution can enhance the salt rejection due to reduced hydrophilicity.
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spelling doaj-art-321eb71a155e4f7c96166c08ad05bcb42025-08-20T03:56:42ZengElsevierDesalination and Water Treatment1944-39862025-07-0132310134110.1016/j.dwt.2025.101341Modification of polyethersulfone with partially reduced graphene oxide and its water purification applicationTeboho R. Motlokoa0Winny K. Maboya1Charity Mbileni-Morema2Sekomeng J. Modise3Bamidele J. Okoli4Vaal University of Technology, Faculty of Applied & Computer Sciences, Department of Natural Sciences, P. Bag x021, Vanderbijlpark 1911, South Africa; Corresponding authors.University of South Africa, School of Science, Engineering and Technology, Institute for Catalysis and Energy Solutions, Florida, P. Bag x6, Roodepoort 1710, South AfricaN.M. EnviroTech Solutions, CSIR, Meiring Naudé Rd, Brummeria, Pretoria 0184, South AfricaVaal University of Technology, Faculty of Applied & Computer Sciences, Department of Natural Sciences, P. Bag x021, Vanderbijlpark 1911, South Africa; Corresponding authors.Vaal University of Technology, Faculty of Applied & Computer Sciences, Department of Natural Sciences, P. Bag x021, Vanderbijlpark 1911, South Africa; Bingham University, Department of Chemical Sciences, Faculty of Science and Technology, Karu P.M.B 005, Nigeria; Corresponding author at: Vaal University of Technology, Faculty of Applied & Computer Sciences, Department of Natural Sciences, P. Bag x021, Vanderbijlpark 1911, South Africa.Nanofiltration is mostly used to treat surface water and wastewater to remove contaminants like heavy metals, small organics, calcium, magnesium and reduce the water hardness. Enhancing membrane properties such as surface characteristics and pore structure can lead to improved separation performance, greater wettability, and a longer lifespan. The study introduces a novel approach for enhancing magnesium ion rejection using a polyether sulphone (PES) membrane embedded with a nanocomposite of partially reduced graphene oxide (rGO). The effect of varying concentration of rGO nanocomposite ranging from 1 to 5 wt% in the fabricated membrane was evaluated in terms of pure water permeation, salt rejection, morphology, and hydrophilicity. EDX analysis of rGO confirmed its partial reduction, evidenced by a decrease in oxygen content from 34.8 % to 27.6 %. The composite membrane demonstrates that incorporating PES and partially rGO improved the wettability, water flux and effective solute rejection due to reduction of the hydrophilic groups. PES with 5 wt% of rGO nanocomposite obtained the highest PWP at 38 L/m2h, whereas the highest rejections of monovalent and divalent salts were obtained by PES with 1 wt% rGO with 77 %, 81 % and 87 % salt rejections for Mg2 + , Na+ and Ca2+, respectively and with the PWP of 30 L/m2h. The decline in salt rejections at higher rGO concentrations suggests that aggregation and increased viscosity inhibited free space formation, negatively affecting permeability. The study shows that partial reduction of GO and its utilization as an additive in the PES casting solution can enhance the salt rejection due to reduced hydrophilicity.http://www.sciencedirect.com/science/article/pii/S1944398625003571PolyethersulfoneGraphene oxideReduced graphene oxideAscorbic acidNanofiltration
spellingShingle Teboho R. Motlokoa
Winny K. Maboya
Charity Mbileni-Morema
Sekomeng J. Modise
Bamidele J. Okoli
Modification of polyethersulfone with partially reduced graphene oxide and its water purification application
Desalination and Water Treatment
Polyethersulfone
Graphene oxide
Reduced graphene oxide
Ascorbic acid
Nanofiltration
title Modification of polyethersulfone with partially reduced graphene oxide and its water purification application
title_full Modification of polyethersulfone with partially reduced graphene oxide and its water purification application
title_fullStr Modification of polyethersulfone with partially reduced graphene oxide and its water purification application
title_full_unstemmed Modification of polyethersulfone with partially reduced graphene oxide and its water purification application
title_short Modification of polyethersulfone with partially reduced graphene oxide and its water purification application
title_sort modification of polyethersulfone with partially reduced graphene oxide and its water purification application
topic Polyethersulfone
Graphene oxide
Reduced graphene oxide
Ascorbic acid
Nanofiltration
url http://www.sciencedirect.com/science/article/pii/S1944398625003571
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AT charitymbilenimorema modificationofpolyethersulfonewithpartiallyreducedgrapheneoxideanditswaterpurificationapplication
AT sekomengjmodise modificationofpolyethersulfonewithpartiallyreducedgrapheneoxideanditswaterpurificationapplication
AT bamidelejokoli modificationofpolyethersulfonewithpartiallyreducedgrapheneoxideanditswaterpurificationapplication