Research

14 pages, 2105 KiB

Open AccessArticle

Sustainable and Eco-Friendly Packaging Films Based on Poly (Vinyl Alcohol) and Glass Flakes

by Iftikhar Ahmed Channa, Jaweria Ashfaq, Sadaf Jamal Gilani, Ali Dad Chandio, Sumra Yousuf, Muhammad Atif Makhdoom and May Nasser bin Jumah

Membranes 2022, 12(7), 701; https://doi.org/10.3390/membranes12070701 - 11 Jul 2022

Cited by 12 | Viewed by 3063

Abstract

The majority of food packaging materials are petroleum-based polymers, which are neither easily recyclable nor ecologically friendly. Packaging films should preferably be transparent, light in weight, and easy to process, as well as mechanically flexible, and they should meet the criteria for food [...] Read more.

The majority of food packaging materials are petroleum-based polymers, which are neither easily recyclable nor ecologically friendly. Packaging films should preferably be transparent, light in weight, and easy to process, as well as mechanically flexible, and they should meet the criteria for food encapsulation. In this study, poly (vinyl alcohol) (PVA)-based films were developed by incorporating glass flakes into the films. The selection of PVA was based on its well-known biodegradability, whereas the selection of glass flakes was based on their natural impermeability to oxygen and moisture. The films were processed using the blade coating method and were characterized in terms of transparency, oxygen transmission rate, mechanical strength, and flexibility. We observed that the incorporation of glass flakes into the PVA matrix did not significantly change the transparency of the PVA films, and they exhibited a total transmittance of around 87% (at 550 nm). When the glass flakes were added to the PVA, a significant reduction in moisture permeation was observed. This reduction was also supported and proven by Bhardwaj’s permeability model. In addition, even after the addition of glass flakes to the PVA, the films remained flexible and showed no degradation in terms of the water vapor transmission rate (WVTR), even after bending cycles of 23,000. The PVA film with glass flakes had decent tensile characteristics, i.e., around >50 MPa. Increasing the concentration of glass flakes also increased the hardness of the films. Finally, a piece of bread was packaged in a well-characterized composite film. We observed that the bread packaged in the PVA film with glass flakes did not show any degradation at all, even after 10 days, whereas the bread piece packaged in a commercial polyethylene bag degraded completely. Based on these results, the developed packaging films are the perfect solution to replace commercial non-biodegradable films. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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12 pages, 2737 KiB

Open AccessArticle

Ultra-Low-Pressure Membrane Filtration for Simultaneous Recovery of Detergent and Water from Laundry Wastewater

by Yusran Khery, Sonia Ely Daniar, Normi Izati Mat Nawi, Muhammad Roil Bilad, Yusuf Wibisono, Baiq Asma Nufida, Ahmadi Ahmadi, Juhana Jaafar, Nurul Huda and Rovina Kobun

Membranes 2022, 12(6), 591; https://doi.org/10.3390/membranes12060591 - 01 Jun 2022

Cited by 5 | Viewed by 2685

Abstract

Reusing water and excess detergent from the laundry industry has become an attractive method to combat water shortages. Membrane filtration is considered an advanced technique and highly attractive due to its excellent advantages. However, the conventional membrane filtration method suffers from membrane fouling, [...] Read more.

Reusing water and excess detergent from the laundry industry has become an attractive method to combat water shortages. Membrane filtration is considered an advanced technique and highly attractive due to its excellent advantages. However, the conventional membrane filtration method suffers from membrane fouling, which restricts its performance and diminishes its economic viability. This study assesses the preliminary performance of submerged, gravity-driven membrane filtration—under ultra-low trans-membrane pressure (△P) of <0.1 bar—to combat membrane fouling issues for detergent and water recovery from laundry wastewater. The results show that even under ultra-low pressure, the membrane suffered from compaction that lowered its permeability by 14% under △P of 6 and 10 kPa, with corresponding permeabilities of 2085 ± 259 and 1791 ± 42 L/(m² h bar). Filtration of a detergent solution also led to up to 8% permeability loss due to membrane fouling. During the filtration of laundry wastewater, 80–91% permeability loss was observed, leading to the lowest flux of 15.6 L/(m²·h) at △P of 10 kPa, 38% lower than △P of 6 kPa (of 25.2 L/(m²·h)). High △P led to both the membrane and the foulant compaction inflating the filtration resistance. The system could recover 83.6% of excess residual detergent, while most micelles were rejected (ascribed from 71% of COD removal). The TDS content could not be retained, disallowing maximum resource recovery. A gravity-driven filtration system can be self-sustained with minimum supervision in residential and industrial laundries. Nevertheless, a detailed study on long-term filtration performance and multiple cleaning cycles is still required in the future. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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14 pages, 2829 KiB

Open AccessEditor’s ChoiceArticle

A Rotary Spacer System for Energy-Efficient Membrane Fouling Control in Oil/Water Emulsion Filtration

by Normi Izati Mat Nawi, Afiq Mohd Lazis, Aulia Rahma, Muthia Elma, Muhammad Roil Bilad, Nik Abdul Hadi Md Nordin, Mohd Dzul Hakim Wirzal, Norazanita Shamsuddin, Hazwani Suhaimi and Norhaniza Yusof

Membranes 2022, 12(6), 554; https://doi.org/10.3390/membranes12060554 - 26 May 2022

Cited by 9 | Viewed by 3145

Abstract

Membrane fouling deteriorates membrane filtration performances. Hence, mitigating membrane fouling is the key factor in sustaining the membrane process, particularly when treating fouling-prone feed, such as oil/water emulsions. The use of spacers has been expanded in the membrane module system, including for membrane [...] Read more.

Membrane fouling deteriorates membrane filtration performances. Hence, mitigating membrane fouling is the key factor in sustaining the membrane process, particularly when treating fouling-prone feed, such as oil/water emulsions. The use of spacers has been expanded in the membrane module system, including for membrane fouling control. This study proposed a rotating spacer system to ameliorate membrane fouling issues when treating an oil/water emulsion. The system’s effectiveness was assessed by investigating the effect of rotating speed and membrane-to-disk gap on the hydraulic performance and the energy input and through computational fluid dynamics (CFD) simulation. The results showed that the newly developed rotary spacer system was effective and energy-efficient for fouling control. The CFD simulation results proved that the spacer rotations induced secondary flow near the membrane surface and imposed shear rate and lift force to exert fouling control. Increasing the rotation speed to an average linear velocity of 0.44 m/s increased the permeability from 126.8 ± 2.1 to 175.5 ± 2.7 Lm⁻²h⁻¹bar⁻¹. The system showed better performance at a lower spacer-to-membrane gap, in which increasing the gap from 0.5 to 2.0 cm lowered the permeability from 175.5 ± 2.7 to 126.7 ± 2.0 Lm⁻²h⁻¹bar⁻¹. Interestingly, the rotary system showed a low energy input of 1.08 to 4.08 × 10⁻³ kWhm⁻³ permeate when run at linear velocities of 0.27 to 0.44 ms⁻¹. Overall, the findings suggest the competitiveness of the rotary spacer system as a method for membrane fouling control. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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20 pages, 4661 KiB

Open AccessArticle

Intermediate Temperature PEFC’s with Nafion^® 211 Membrane Electrolytes: An Experimental and Numerical Study

by Oliver Fernihough, Mohammed S. Ismail and Ahmad El-kharouf

Membranes 2022, 12(4), 430; https://doi.org/10.3390/membranes12040430 - 15 Apr 2022

Cited by 5 | Viewed by 2737

Abstract

This paper evaluates the performance of Nafion 211 at elevated temperatures up to 120 °C using an experimentally validated model. Increasing the fuel cell operating temperature could have many key benefits at the cell and system levels. However, current research excludes this due [...] Read more.

This paper evaluates the performance of Nafion 211 at elevated temperatures up to 120 °C using an experimentally validated model. Increasing the fuel cell operating temperature could have many key benefits at the cell and system levels. However, current research excludes this due to issues with membrane durability. Modelling is used to investigate complex systems to gain further information that is challenging to obtain experimentally. Nafion 211 is shown to have some interesting characteristics at elevated temperatures previously unreported, the first of which is that the highest performance reported is at 100 °C and 100% relative humidity. The model was trained on the experimental data and then used to predict the behaviour in the membrane region to understand how the fuel cell performs at varying temperatures and pressures. The model showed that the best membrane performance comes from a 100 °C operating temperature, with much better performance yielded from a higher pressure of 3 bar. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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17 pages, 3704 KiB

Open AccessArticle

A Contrastive Study of Self-Assembly and Physical Blending Mechanism of TiO₂ Blended Polyethersulfone Membranes for Enhanced Humic Acid Removal and Alleviation of Membrane Fouling

by Abdul Latif Ahmad, Nuur Fahanis Che Lah, Nur Amelia Norzli and Wen Yu Pang

Membranes 2022, 12(2), 162; https://doi.org/10.3390/membranes12020162 - 29 Jan 2022

Cited by 4 | Viewed by 2177

Abstract

In this study, membrane fabrication was achieved by two different methods: (i) self-assembly and (ii) physical blending of TiO₂ in PES membrane for humic acid filtration. The TiO₂ nanoparticles were self-assembled by using TBT as the precursor and pluronic F127 as [...] Read more.

In this study, membrane fabrication was achieved by two different methods: (i) self-assembly and (ii) physical blending of TiO₂ in PES membrane for humic acid filtration. The TiO₂ nanoparticles were self-assembled by using TBT as the precursor and pluronic F127 as triblock copolymers around the membrane pores. This was achieved by manipulating the hydrolysis and condensation reaction of TBT precursors during the non-solvent induced phase separation (NIPS) process. On the other hand, the TiO₂ was physically blended as a comparison to the previous method. The characteristic of the membrane was analysed to explore the possibility of enhancing the membrane antifouling mechanism and the membrane flux. The membrane morphology, pore size, porosity, and contact angle were characterised. Both methods proved to be able to enhance the antifouling properties and flux performance. The HA rejection increased up to 95% with membrane flux 55.40 kg m⁻² h⁻¹. The rejection rate was not significantly improved for either method. However, the antifouling characteristic for the self-assembly TiO₂/PES membrane was better than the physically blended membrane. This was found to be due to the high surface hydrophilicity of the MM membrane, which repelled the hydrophobic HA and consequently blocked the HA adsorption onto the surface. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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15 pages, 17012 KiB

Open AccessArticle

Research on Energy and Economics of Self-Made Catalyst-Coated Membrane for Fuel Cell under Different Oxidants

by Qiang Bai, Chuangyu Hsieh and Shaobo Li

Membranes 2022, 12(2), 128; https://doi.org/10.3390/membranes12020128 - 21 Jan 2022

Viewed by 2054

Abstract

In the context of global warming, clean energy represented by fuel cells has ushered in a window period of rapid development; however, most research mainly focuses on the improvement of catalysts and performance, and there is very little research on the performance differences [...] Read more.

In the context of global warming, clean energy represented by fuel cells has ushered in a window period of rapid development; however, most research mainly focuses on the improvement of catalysts and performance, and there is very little research on the performance differences and energy consumption between different oxidants. In this paper, the performance differences of fuel cells with different oxidants (air and oxygen) are studied using a self-made CCM, and the economic aspect is calculated from the perspective of power improvement and energy consumption. Firstly, the CCM and GDL are prepared, and the hydrophilicity and hydrophobicity of GDL are realized by the addition of PTFE and SiO₂, respectively. Secondly, through the experiment, it is found that the fuel cell can achieve the best comprehensive performance at 60 °C, and the use of oxygen can achieve the highest power increase, 117.1%, compared with air. Finally, from the perspective of economics, after excluding the power consumed for preparing oxygen, the use of oxygen as an oxidant still achieved a net power increase of 29.512%. The research in this paper clearly shows that using oxygen instead of air can greatly improve performance and is good economically, which makes it a useful exploration for the research of fuel cells. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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18 pages, 3993 KiB

Open AccessArticle

Non-Solvent Influence of Hydrophobic Polymeric Layer Deposition on PVDF Hollow Fiber Membrane for CO₂ Gas Absorption

by Abdul Latif Ahmad, Amir Ikmal Hassan and Leo Choe Peng

Membranes 2022, 12(1), 41; https://doi.org/10.3390/membranes12010041 - 28 Dec 2021

Viewed by 1838

Abstract

The implementation of hydrophobicity on membranes is becoming crucial in current membrane technological development, especially in membrane gas absorption (MGA). In order to prevent membrane wetting, a polypropylene (PP) dense layer coating was deposited on a commercial poly(vinylidene fluoride) (PVDF) hollow fiber membrane [...] Read more.

The implementation of hydrophobicity on membranes is becoming crucial in current membrane technological development, especially in membrane gas absorption (MGA). In order to prevent membrane wetting, a polypropylene (PP) dense layer coating was deposited on a commercial poly(vinylidene fluoride) (PVDF) hollow fiber membrane as a method of enhancing surface hydrophobicity. The weight concentration of PP pellets was varied from 10 mg mL⁻¹ to 40 mg mL⁻¹ and dissolved in xylene. A two-step dip coating was implemented where the PVDF membrane was immersed in a non-solvent followed by a polymer coating solution. The effects of the modified membrane with the non-solvent methyl ethyl ketone (MEK) and without the non–solvent was investigated over all weight concentrations of the coating solution. The SEM investigation found that the modified membrane surface transfiguration formed microspherulites that intensified as PP concentration increased with and without MEK. To understand the coating formation further, the solvent–non-solvent compatibility with the polymer was also discussed in this study. The membrane characterizations on the porosity, the contact angle, and the FTIR spectra were also conducted in determining the polymer coating properties. Hydrophobic membrane was achieved up to 119.85° contact angle and peak porosity of 87.62% using MEK as the non-solvent 40 mg mL⁻¹ PP concentration. The objective of the current manuscript was to test the hydrophobicity and wetting degree of the coating layer. Hence, physical absorption via the membrane contactor using CO₂ as the feed gas was carried out. The maximum CO₂ flux of 3.33 × 10⁻⁴ mol m⁻² s⁻¹ was achieved by 25 mg modified membrane at a fixed absorbent flow rate of 100 mL min⁻¹ while 40 mg modified membrane showed better overall flux stability. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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13 pages, 3133 KiB

Open AccessArticle

Graphene Oxide-Doped Polymer Inclusion Membrane for Remediation of Pharmaceutical Contaminant of Emerging Concerns: Ibuprofen

by Abdul Latif Ahmad, Oluwasola Idowu Ebenezer, Noor Fazliani Shoparwe and Suzylawati Ismail

Membranes 2022, 12(1), 24; https://doi.org/10.3390/membranes12010024 - 25 Dec 2021

Cited by 12 | Viewed by 2860

Abstract

The application of polymer inclusion membranes (PIMs) for the aquatic remediation of several heavy metals, dyes, and nutrients has been extensively studied. However, its application in treating organic compounds such as Ibuprofen, an emerging pharmaceutical contaminant that poses potential environmental problems, has not [...] Read more.

The application of polymer inclusion membranes (PIMs) for the aquatic remediation of several heavy metals, dyes, and nutrients has been extensively studied. However, its application in treating organic compounds such as Ibuprofen, an emerging pharmaceutical contaminant that poses potential environmental problems, has not been explored satisfactorily. Therefore, graphene oxide (GO) doped PIMs were fabricated, characterized, and applied to extract aqueous Ibuprofen at varied pH conditions. The doped PIMs were synthesized using a low concentration of Aliquat 336 as carrier and 0, 0.15, 0.45, and 0.75% GO as nanoparticles in polyvinyl chloride (PVC) base polymer without adding any plasticizer. The synthesized PIM was characterized by SEM, FTIR, physical, and chemical stability. The GO doped PIM was well plasticized and had an optimal Ibuprofen extraction efficiency of about 84% at pH of 10 and 0.75% GO concentration. Furthermore, the GO doped PIM’s chemical stability indicates better stability in acidic solution than in the alkaline solution. This study demonstrates that the graphene oxide-doped PIM significantly enhanced the extraction of Ibuprofen at a low concentration. However, further research is required to improve its stability and efficiency for the remediation of the ubiquitous Ibuprofen in the aquatic environment. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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12 pages, 3329 KiB

Open AccessArticle

Preparation of Hydrophobic PET Track-Etched Membranes for Separation of Oil–Water Emulsion

by Ilya V. Korolkov, Asiya R. Narmukhamedova, Galina B. Melnikova, Indira B. Muslimova, Arman B. Yeszhanov, Zh K. Zhatkanbayeva, Sergei A. Chizhik and Maxim V. Zdorovets

Membranes 2021, 11(8), 637; https://doi.org/10.3390/membranes11080637 - 17 Aug 2021

Cited by 20 | Viewed by 3449

Abstract

The paper describes the separation of an oil–water emulsion by filtration using poly(ethylene terephthalate) track-etched membranes (PET TeMs) with regular pore geometry and narrow pore size distribution. PET TeMs were modified with trichloro(octyl)silane to increase their hydrophobic properties. Conditions for the modification of [...] Read more.

The paper describes the separation of an oil–water emulsion by filtration using poly(ethylene terephthalate) track-etched membranes (PET TeMs) with regular pore geometry and narrow pore size distribution. PET TeMs were modified with trichloro(octyl)silane to increase their hydrophobic properties. Conditions for the modification of PET TeMs with trichloro(octyl)silane were investigated. The results of changes in the pore diameters and the contact angle depend on the concentration of trichloro(octyl)silane and the soaking time are presented. The obtained samples were characterized by FTIR, AFM, SEM-EDX and gas-permeability test. Chloroform–water and cetane–water emulsions have been used as a test liquid for oil–water separation. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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18 pages, 8965 KiB

Open AccessArticle

γ-Valerolactone as Bio-Based Solvent for Nanofiltration Membrane Preparation

by Muhammad Azam Rasool and Ivo F. J. Vankelecom

Membranes 2021, 11(6), 418; https://doi.org/10.3390/membranes11060418 - 31 May 2021

Cited by 13 | Viewed by 4330

Abstract

γ-Valerolactone (GVL) was selected as a renewable green solvent to prepare membranes via the process of phase inversion. Water and ethanol were screened as sustainable non-solvents to prepare membranes for nanofiltration (NF). Scanning electron microscopy was applied to check the membrane morphology, while [...] Read more.

γ-Valerolactone (GVL) was selected as a renewable green solvent to prepare membranes via the process of phase inversion. Water and ethanol were screened as sustainable non-solvents to prepare membranes for nanofiltration (NF). Scanning electron microscopy was applied to check the membrane morphology, while aqueous rose Bengal (RB) and magnesium sulphate (MgSO₄) feed solutions were used to screen performance. Cellulose acetate (CA), polyimide (PI), cellulose triacetate (CTA), polyethersulfone (PES) and polysulfone (PSU) membranes were fine-tuned as materials for preparation of NF-membranes, either by selecting a suitable non-solvent for phase inversion or by increasing the polymer concentration in the casting solution. The best membranes were prepared with CTA in GVL using water as non-solvent: with increasing CTA concentration (10 wt% to 17.5 wt%) in the casting solution, permeance decreased from 15.9 to 5.5 L/m²·h·bar while RB rejection remained higher than 94%. The polymer solubilities in GVL were rationalized using Hansen solubility parameters, while membrane performances and morphologies were linked to viscosity measurements and cloudpoint determination of the casting solutions to better understand the kinetic and thermodynamic aspects of the phase inversion process. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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14 pages, 2595 KiB

Open AccessArticle

[EMIM][Tf2N]-Modified Silica as Filler in Mixed Matrix Membrane for Carbon Dioxide Separation

by Siti Nur Alwani Shafie, Nik Abdul Hadi Md Nordin, Muhammad Roil Bilad, Nurasyikin Misdan, Norazlianie Sazali, Zulfan Adi Putra, Mohd Dzul Hakim Wirzal, Alamin Idris, Juhana Jaafar and Zakaria Man

Membranes 2021, 11(5), 371; https://doi.org/10.3390/membranes11050371 - 19 May 2021

Cited by 10 | Viewed by 2635

Abstract

This study focuses on the effect of modified silica fillers by [EMIN][Tf₂N] via physical adsorption on the CO₂ separation performance of a mixed matrix membrane (MMM). The IL-modified silica was successfully synthesized as the presence of fluorine element was observed [...] Read more.

This study focuses on the effect of modified silica fillers by [EMIN][Tf₂N] via physical adsorption on the CO₂ separation performance of a mixed matrix membrane (MMM). The IL-modified silica was successfully synthesized as the presence of fluorine element was observed in both Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometer (XPS) analyses. The prepared MMMs with different loadings of the IL-modified silica were then compared with an unmodified silica counterpart and neat membrane. The morphology of IL-modified MMMs was observed to have insignificant changes, while polymer chains of were found to be slightly more flexible compared to their counterpart. At 2 bar of operating pressure, a significant increase in performance was observed with the incorporation of 3 wt% Sil-IL fillers compared to that of pure polycarbonate (PC). The permeability increased from 353 to 1151 Barrer while the CO₂/CH₄ selectivity increased from 20 to 76. The aforementioned increment also exceeded the Robeson upper bound. This indicates that the incorporation of fillers surface-modified with ionic liquid in an organic membrane is worth exploring for CO₂ separation. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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13 pages, 2110 KiB

Open AccessArticle

Effect of Membrane Materials and Operational Parameters on Performance and Energy Consumption of Oil/Water Emulsion Filtration

by Nafiu Umar Barambu, Muhammad Roil Bilad, Nurul Huda, Nik Abdul Hadi Md Nordin, Mohamad Azmi Bustam, Aris Doyan and Jumardi Roslan

Membranes 2021, 11(5), 370; https://doi.org/10.3390/membranes11050370 - 19 May 2021

Cited by 12 | Viewed by 2536

Abstract

Membrane technology is one of reliable options for treatment of oil/water emulsion. It is highly attractive because of its effectiveness in separating fine oil droplets of <2 µm sizes, which is highly challenging for other processes. However, the progress for its widespread implementations [...] Read more.

Membrane technology is one of reliable options for treatment of oil/water emulsion. It is highly attractive because of its effectiveness in separating fine oil droplets of <2 µm sizes, which is highly challenging for other processes. However, the progress for its widespread implementations is still highly restricted by membrane fouling. Most of the earlier studies have demonstrated the promise of achieving more sustained filtration via membrane material developments. This study addresses issues beyond membrane development by assessing the impact of membrane material (blend of polysulfone, PSF and polyethylene glycol, PEG), operational pressure, and crude oil concentration on the filtration performance of oil/water emulsion. The filtration data were then used to project the pumping energy for a full-scale system. Results show that fouling resistant membrane offered high oil/water emulsion permeability, which translated into a low energy consumption. The oil/water emulsion permeability was improved by three-fold from 45 ± 0 to 139 ± 1 L/(m² h bar) for PSF/PEG-0 membrane in comparison to the most optimum one of PSF/PEG-60. It corresponded to an energy saving of up to ~66%. The pumping energy could further be reduced from 27.0 to 7.6 Wh/m³ by operation under ultra-low pressure from 0.2 to 0.05 bar. Sustainable permeability could be achieved when treating 1000 ppm oil/water emulsion, but severe membrane fouling was observed when treating emulsion containing crude oils of >3000 ppm to a point of no flux. Full article

(This article belongs to the Special Issue Advanced Polymeric Membranes for Energy & Environment)

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