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Abuhasheesh YH, Hegab HM, Wadi VS, Al Marzooqi F, Banat F, Aljundi IH, Hasan SW. Phase inverted hydrophobic polyethersulfone/iron oxide-oleylamine ultrafiltration membranes for efficient water-in-oil emulsion separation. CHEMOSPHERE 2023:139431. [PMID: 37422217 DOI: 10.1016/j.chemosphere.2023.139431] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/06/2023] [Accepted: 07/04/2023] [Indexed: 07/10/2023]
Abstract
Exploration and transportation of oil offshore can result in oil spills that cause a wide range of adverse environmental consequences and destroy aquatic life. Membrane technology outperformed the conventional procedures for oil emulsion separation due to its improved performance, reduced cost, removal capacity, and greater eco-friendly. In this study, a hydrophobic iron oxide-oleylamine (Fe-Ol) nanohybrid was synthesized and incorporated into polyethersulfone (PES) to prepare novel PES/Fe-Ol hydrophobic ultrafiltration (UF) mixed matrix membranes (MMMs). Several characterization techniques were performed to characterize the synthesized nanohybrid and fabricated membranes, including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), contact angle, and zeta potential. The membranes' performance was assessed using a surfactant-stabilized (SS) water-in-hexane emulsion as a feed and a dead-end vacuum filtration setup. The incorporation of the nanohybrid enhanced the hydrophobicity, porosity, and thermal stability of the composite membranes. At 1.5 wt% Fe-Ol nanohybrid, the modified PES/Fe-Ol MMM membranes reported high water rejection efficiency of 97.4% and 1020.4 LMH filtrate flux. The re-usability and antifouling properties of the membrane were examined over five filtration cycles, demonstrating its great potential for use in water-in-oil separation.
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Affiliation(s)
- Yazan H Abuhasheesh
- Center for Membranes and Advanced Water Technology (CMAT), Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
| | - Hanaa M Hegab
- Center for Membranes and Advanced Water Technology (CMAT), Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
| | - Vijay S Wadi
- Center for Membranes and Advanced Water Technology (CMAT), Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
| | - Faisal Al Marzooqi
- Center for Membranes and Advanced Water Technology (CMAT), Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
| | - Fawzi Banat
- Center for Membranes and Advanced Water Technology (CMAT), Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
| | - Isam H Aljundi
- Chemical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran, 31261, Saudi Arabia; Interdisciplinary Research Center for Membranes and Water Security, King Fahd University of Petroleum and Minerals, Saudi Arabia
| | - Shadi W Hasan
- Center for Membranes and Advanced Water Technology (CMAT), Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates.
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Mecha AC, Chollom MN, Babatunde BF, Tetteh EK, Rathilal S. Versatile Silver-Nanoparticle-Impregnated Membranes for Water Treatment: A Review. MEMBRANES 2023; 13:432. [PMID: 37103859 PMCID: PMC10143275 DOI: 10.3390/membranes13040432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
Increased affordability, smaller footprint, and high permeability quality that meets stringent water quality standards have accelerated the uptake of membranes in water treatment. Moreover, low pressure, gravity-based microfiltration (MF) and ultrafiltration (UF) membranes eliminate the use of electricity and pumps. However, MF and UF processes remove contaminants by size exclusion, based on membrane pore size. This limits their application in the removal of smaller matter or even harmful microorganisms. There is a need to enhance the membrane properties to meet needs such as adequate disinfection, flux amelioration, and reduced membrane fouling. To achieve these, the incorporation of nanoparticles with unique properties in membranes has potential. Herein, we review recent developments in the impregnation of polymeric and ceramic microfiltration and ultrafiltration membranes with silver nanoparticles that are applied in water treatment. We critically evaluated the potential of these membranes in enhanced antifouling, increased permeability quality and flux compared to uncoated membranes. Despite the intensive research in this area, most studies have been performed at laboratory scale for short periods of time. There is a need for studies that assess the long-term stability of the nanoparticles and the impact on disinfection and antifouling performance. These challenges are addressed in this study and future directions.
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Affiliation(s)
- Achisa C. Mecha
- Renewable Energy, Environment, Nanomaterials, and Water Research Group, Department of Chemical and Process Engineering, Moi University, P.O. Box 3900, Eldoret 30100, Kenya
| | - Martha N. Chollom
- Environmental Pollution and Remediation Research Group, Department of Chemical Engineering, Mangosuthu University of Technology, P.O. Box 12363, Durban 4026, South Africa
| | - Bakare F. Babatunde
- Environmental Pollution and Remediation Research Group, Department of Chemical Engineering, Mangosuthu University of Technology, P.O. Box 12363, Durban 4026, South Africa
| | - Emmanuel K. Tetteh
- Green Engineering Research Group, Department of Chemical Engineering, Faculty of Engineering and the Built Environment, Durban University of Technology, P.O. Box 1334, Durban 4001, South Africa
| | - Sudesh Rathilal
- Green Engineering Research Group, Department of Chemical Engineering, Faculty of Engineering and the Built Environment, Durban University of Technology, P.O. Box 1334, Durban 4001, South Africa
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Al-Kadhi NS, Adel Pashameah R, Mwafy EA, Al-Ahmadi AN, Ahmed HA, Mostafa AM, Alamro FS, Rezk RA. Spinel lithium titanate anode / polyether sulfone nanocomposite synthesized by pulsed laser ablation method for optoelectronic applications. JOURNAL OF SAUDI CHEMICAL SOCIETY 2023. [DOI: 10.1016/j.jscs.2023.101626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
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Amouamouha M, Gholikandi GB, Walker TW. Experimental investigation of the performance of anaerobic membrane bioreactor with electrolytic regeneration (AMBER) for challenges and options in wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 844:157080. [PMID: 35810911 DOI: 10.1016/j.scitotenv.2022.157080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/20/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Significant changes in wastewater services are necessary for achieving the sustainable development goals (SDGs), by utilizing resource recovery, recycle, and reuse in urban wastewater-treatment plants. Based on recent experiences, to improve the filtration behavior of a membrane bioreactor, a hybrid system including an upgraded anaerobic baffled reactor coupled with an electrolysis process and a nanocomposite-membrane was developed. The system, called an anaerobic membrane bioreactor with electrolytic regeneration (AMBER), is a bio-electrochemical process that is expected to be simultaneously efficient in both biogas augmentation and fouling mitigation. The goals were to enhance the stability and efficiency of the anaerobic membrane bioreactor. The integration of the electrolytic process with the ABR (EABR) using a pair of iron electrodes enhanced the removal of contaminants in the ABR while successfully maintained pH in the optimum range for anaerobic digestion (6.8 to 7.2). Then, the performance of AMBER in pollutant removal, including organic load, suspended solids, and microbial load, were investigated over 240 days. The results showed that configuration considerably enhanced permeate flux, as it reduced the deposition of extracellular polymeric substances (EPS) on the surface of the nanocomposite membrane, leading to a reduction in membrane fouling. EPS was extracted and quantified to compare the effect of biogas backwash on the function of the membrane reactor. After 7 d of operation with a daily biogas backwash, the flux reduction was approximately 13 % for the conventional combination of the anaerobic baffled reactor and the membrane bioreactor (AMBR), while it was limited to 4 % in AMBER. After cleaning by the biogas, EPS formation decreased 63 % in AMBER when compared to the AMBR. The results revealed that AMBER can be considered an environmentally competitive bioenergy technology for wastewater treatment with the purpose of water recovery and reuse, employing optimized operational conditions, application of antifouling membranes, and electrically-based strategies.
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Affiliation(s)
- Maryam Amouamouha
- Chemical and Biological Engineering, South Dakota School of Mines & Technology, Rapid City, SD, USA
| | | | - Travis W Walker
- Chemical and Biological Engineering, South Dakota School of Mines & Technology, Rapid City, SD, USA.
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Yu Y, Zhou Z, Huang G, Cheng H, Han L, Zhao S, Chen Y, Meng F. Purifying water with silver nanoparticles (AgNPs)-incorporated membranes: Recent advancements and critical challenges. WATER RESEARCH 2022; 222:118901. [PMID: 35933814 DOI: 10.1016/j.watres.2022.118901] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/19/2022] [Accepted: 07/23/2022] [Indexed: 06/15/2023]
Abstract
In the face of the growing global water crisis, membrane technology is a promising means of purifying water and wastewater. Silver nanoparticles (AgNPs) have been widely used to improve membrane performance, for antibiofouling, and to aid in photocatalytic degradation, thermal response, and electro-conductivity. However, several critical issues such as short antimicrobial periods, trade-off effects and silver inactivation seriously restrict the engineering application of AgNPs-incorporated membranes. In addition, there is controversy around the use of AgNPs given the toxic preparation process and environmental/biological risks. Hence, it is of great significance to summarize and analyze the recent developments and critical challenges in the use of AgNPs-incorporated membranes in water and wastewater treatment, and to propose potential solutions. We reviewed the different properties and functions of AgNPs and their corresponding applications in AgNPs-incorporated membranes. Recently, multifunctional, novel AgNP-incorporated membranes combined with other functional materials have been developed with high-performance. We further clarified the synergistic mechanisms between AgNPs and these novel nanomaterials and/or polymers, and elucidated their functions and roles in membrane separation. Finally, the critical challenges of AgNPs-incorporated membranes and the proposed solutions were outlined: i) Prolonging the antimicrobial cycle through long-term and controlled AgNPs release; ii) Overcoming the trade-off effect and organic fouling of the AgNPs-incorporated membranes; iii) Preparation of sustainable AgNPs-incorporated membranes; iv) Addressing biotoxicity induced by AgNPs; and v) Deactivation of AgNPs-incorporated membrane. Overall, this review provides a comprehensive discussion of the advancements and challenges of AgNPs-incorporated membranes and guides the development of more robust, multi-functional and sustainable AgNPs-incorporated membranes.
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Affiliation(s)
- Yuanyuan Yu
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; Chongqing Engineering Research Center of Rural Cleaner Production, Chongqing, 400715, China
| | - Zhongbo Zhou
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; Chongqing Engineering Research Center of Rural Cleaner Production, Chongqing, 400715, China.
| | - Guocheng Huang
- Department of Environmental Science and Engineering, Fuzhou University, Minhou, Fujian, 350108, China
| | - Hong Cheng
- College of Environment and Ecology, Chongqing University, Chongqing, 400044, China
| | - Le Han
- College of Environment and Ecology, Chongqing University, Chongqing, 400044, China
| | - Shanshan Zhao
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yucheng Chen
- College of Resources and Environment, Southwest University, Chongqing, 400715, China; Chongqing Engineering Research Center of Rural Cleaner Production, Chongqing, 400715, China
| | - Fangang Meng
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510006, China
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Reduced Graphene Oxide Membranes as Potential Self-Assembling Filter for Wastewater Treatment. MINERALS 2020. [DOI: 10.3390/min11010015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This work focuses on the investigation of the capability of reduced graphene oxide (rGO) filters to remove metals from various wastewater. The process to produce rGO membranes is reported and discussed, as well as their ability to capture ions in complex solutions, such as tap or industrial wastewater. Multi-ion solutions, containing Cu2+, Fe3+, Ni2+, and Mn2+ to simulate mine wastewater, or Ca2+ and Mg2+ to mimic drinkable water, were used as models. In mono-ionic solutions, the best capture efficiency values were proved for Ca2+, Fe3+, and Ni2+ ions, while a matrix effect was found for multi-ion solutions. However, interesting capture efficiencies were measured in the range of 30–90%, depending on the specific ion, for both single and multi-ion solutions. An attempt is proposed to correlate ions capture efficiency with ions characteristics, such as ionic radius or charge. Combining a satisfactory capture efficiency with low costs and ease of treatment unit operations, the approach here proposed is considered promising to replace other more complex and expensive filtration techniques.
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Curtin AM, Thibodeau MC, Buckley HL. The Best-Practice Organism for Single-Species Studies of Antimicrobial Efficacy against Biofilms Is Pseudomonas aeruginosa. MEMBRANES 2020; 10:E211. [PMID: 32872560 PMCID: PMC7559251 DOI: 10.3390/membranes10090211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 12/23/2022]
Abstract
As potable water scarcity increases across the globe; it is imperative to identify energy and cost-effective processes for producing drinking-water from non-traditional sources. One established method is desalination of brackish and seawater via reverse osmosis (RO). However, the buildup of microorganisms at the water-membrane interface, known as biofouling, clogs RO membranes over time, increasing energy requirements and cost. To investigate biofouling mitigation methods, studies tend to focus on single-species biofilms; choice of organism is crucial to producing useful results. To determine a best-practice organism for studying antimicrobial treatment of biofilms, with specific interest in biofouling of RO membranes, we answered the following two questions, each via its own semi-systematic review: 1. Which organisms are commonly used to test antimicrobial efficacy against biofilms on RO membranes? 2. Which organisms are commonly identified via genetic analysis in biofilms on RO membranes? We then critically review the results of two semi-systematic reviews to identify pioneer organisms from the listed species. We focus on pioneer organisms because they initiate biofilm formation, therefore, inhibiting these organisms specifically may limit biofilm formation in the first place. Based on the analysis of the results, we recommend utilizing Pseudomonas aeruginosa for future single-species studies focused on biofilm treatment including, but not limited to, biofouling of RO membranes.
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Affiliation(s)
| | | | - Heather L. Buckley
- Green Safe Water Lab, Civil Engineering Department, University of Victoria, Victoria, BC V8P 5C2, Canada; (A.M.C.); (M.C.T.)
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Xu F, Zhao C, Lee CH, Wang W, Xu Q. Anti-Biofouling Performance of an Immobilized Indigenous Quorum Quenching Bacterium Bacillus cereus HG10 and Its Influence on the Microbial Community in a Bioreactor. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16193777. [PMID: 31597309 PMCID: PMC6802356 DOI: 10.3390/ijerph16193777] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 10/04/2019] [Accepted: 10/04/2019] [Indexed: 11/16/2022]
Abstract
Quorum quenching-membrane bioreactors (QQ-MBRs) have been studied widely in recent decades. However, limited information is known about the influence of QQ on the microbial community. In this study, the indigenous QQ bacterium Bacillus cereus HG10 was immobilized and used to control biofouling in a bioreactor. QQ beads caused extracellular polymeric substance reduction and significantly hindered biofilm formation on a submerged membrane. Community profiling of 16S rRNA gene amplicons revealed that QQ beads dramatically altered the bacterial community structure in activated sludge but not in biofilm. Bacterial structure in the presence of QQ beads showed a clear divergence from that of the control groups at phylum, class, order, family, and genus taxonomic ranks. A significant enrichment of several bacterial genera, including Acinetobacter, Aeromonas, Delftia, Bacillus, and Pseudomonas, and depletion of over 12 bacterial genera were observed. These findings would contribute to a better understanding of why and how immobilized QQ bacteria impair membrane biofouling in QQ-MBRs.
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Affiliation(s)
- Fangfang Xu
- College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China.
| | - Chang Zhao
- Shenzhen Engineering Laboratory for Recycled Eco-efficient Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Xili University Town, Shenzhen 518055, China.
| | - Chuang Hak Lee
- Fairylands Environmental Sci-Tech (Shenzhen) Crop. Ltd., Shenzhen 518055, China.
| | - Wenzhao Wang
- Shenzhen Engineering Laboratory for Recycled Eco-efficient Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Xili University Town, Shenzhen 518055, China.
- Fairylands Environmental Sci-Tech (Shenzhen) Crop. Ltd., Shenzhen 518055, China.
| | - Qiyong Xu
- Shenzhen Engineering Laboratory for Recycled Eco-efficient Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Xili University Town, Shenzhen 518055, China.
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Le HQ, Sowe A, Chen SS, Duong CC, Ray SS, Cao TND, Nguyen NC. Exploring Nanosilver-Coated Hollow Fiber Microfiltration to Mitigate Biofouling for High Loading Membrane Bioreactor. Molecules 2019; 24:E2345. [PMID: 31242707 PMCID: PMC6631756 DOI: 10.3390/molecules24122345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 06/21/2019] [Accepted: 06/24/2019] [Indexed: 11/16/2022] Open
Abstract
For the first time, a nanosilver-coated hollow fiber microfiltration (MF) was fabricated by a simple chemical reduction method, then tested for membrane biofouling mitigation study under extreme high mixed liquor suspended solid (MLSS) concentration for long term. This study presents a simple and novel technique to modify a commercially available MF membrane using silver nanoparticles (AgNPs) followed by an investigation of mitigating membrane biofouling potentials using this modified membrane to compare with an unmodified membrane for 60-day operation period. The modified membranes showed that AgNPs was attached to the MF-membrane successfully with a high density of 119.85 ± 5.42 mg/m2. After long-term testing of 60 days in membrane bioreactor with a MLSS concentration of 11,000 mg/L, specific flux of the AgNPs coated MF (AgNPs-MF) decreased 59.7%, while the specific flux of the unmodified membrane dropped 81.8%, resulted from the increase of transmembrane vacuum pressure for the AgNPs-MF was lower than that of the unmodified one. The resistance-in-series model was used to calculate the resistance coefficients of membrane modules, and the result showed that the cake layer resistance coefficient of the unmodified membrane was 2.7 times higher than that of the AgNPs-MF after the 60-day operation, confirming that AgNPs displayed great antimicrobial properties to mitigate membrane biofouling under such high MLSS.
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Affiliation(s)
- Huy Quang Le
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd. Taipei 10608, Taiwan; (H.Q.L.); (A.S.); (C.C.D.); (S.S.R.); (T.N.-D.C.)
- Faculty of Environment and Natural Resources, Dalat University, 01 Phu Dong Thien Vuong Street, Da Lat City 66000, Vietnam;
| | - Alieu Sowe
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd. Taipei 10608, Taiwan; (H.Q.L.); (A.S.); (C.C.D.); (S.S.R.); (T.N.-D.C.)
| | - Shiao-Shing Chen
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd. Taipei 10608, Taiwan; (H.Q.L.); (A.S.); (C.C.D.); (S.S.R.); (T.N.-D.C.)
| | - Chinh Cong Duong
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd. Taipei 10608, Taiwan; (H.Q.L.); (A.S.); (C.C.D.); (S.S.R.); (T.N.-D.C.)
- Southern Institute of Water Resources Research, 658 Vo Van Kiet Street, District 5, Ho Chi Minh City 700000, Vietnam
| | - Saikat Sinha Ray
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd. Taipei 10608, Taiwan; (H.Q.L.); (A.S.); (C.C.D.); (S.S.R.); (T.N.-D.C.)
| | - Thanh Ngoc-Dan Cao
- Institute of Environmental Engineering and Management, National Taipei University of Technology, No.1, Sec. 3, Zhongxiao E. Rd. Taipei 10608, Taiwan; (H.Q.L.); (A.S.); (C.C.D.); (S.S.R.); (T.N.-D.C.)
- Nguyen Tat Thanh University, 300A Nguyen Tat Thanh Street, District 4, Ho Chi Minh City 700000, Vietnam
| | - Nguyen Cong Nguyen
- Faculty of Environment and Natural Resources, Dalat University, 01 Phu Dong Thien Vuong Street, Da Lat City 66000, Vietnam;
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Synthesis and Characterization of a High Flux Nanocellulose-Cellulose Acetate Nanocomposite Membrane. MEMBRANES 2019; 9:membranes9060070. [PMID: 31174312 PMCID: PMC6630560 DOI: 10.3390/membranes9060070] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/01/2019] [Accepted: 06/04/2019] [Indexed: 11/16/2022]
Abstract
Despite the advantages of membrane processes, their high energy requirement remains a major challenge. Fabrication of nanocomposite membranes by incorporating various nanomaterials in the polymer matrix has shown promise for enhancing membrane flux. In this study, we embed functionalized cellulose nanofibers (CNFs) with high aspect ratios in the polymer matrix to create hydrophilic nanochannels that reduce membrane resistance and facilitate the facile transport of water molecules through the membrane. The results showed that the incorporation of 0.1 wt % CNF into the polymer matrix did not change the membrane flux (~15 L · m - 2 · h - 1 ) and Bovine Serum Albumin (BSA) Fraction V rejection, while increasing the CNF content to 0.3 wt % significantly enhanced the flux by seven times to ~100 L · m - 2 · h - 1 , but the rejection was decreased to 60-70%. Such a change in membrane performance was due to the formation of hydrophilic nanochannels by the incorporation of CNF (corroborated by the SEM images), decreasing the membrane resistance, and thus enhancing the flux. When the concentration of the CNF in the membrane matrix was further increased to 0.6 wt %, no further increase in the membrane flux was observed, however, the BSA rejection was found to increase to 85%. Such an increase in the rejection was related to the electrostatic repulsion between the negatively-charged CNF-loaded nanochannels and the BSA, as demonstrated by zeta potential measurements. SEM images showed the bridging effect of the CNF in the nanochannels with high CNF contents.
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