scholarly journals Reduction of Biofouling of a Microfiltration Membrane Using Amide Functionalities—Hydrophilization without Changes in Morphology

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1379
Author(s):  
Daniel Breite ◽  
Marco Went ◽  
Andrea Prager ◽  
Mathias Kühnert ◽  
Agnes Schulze
Keyword(s):  
Membrane Fouling ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Aqueous Media ◽  
Soxhlet Extraction ◽  
Hydrophobic Membrane ◽  
Average Pore ◽  
Water Contact ◽  
Microfiltration Membrane ◽  
Membrane Performance

A major goal of membrane science is the improvement of the membrane performance and the reduction of fouling effects, which occur during most aqueous filtration applications. Increasing the surface hydrophilicity can improve the membrane performance (in case of aqueous media) and decelerates membrane fouling. In this study, a PES microfiltration membrane (14,600 L m−2 h−1 bar−1) was hydrophilized using a hydrophilic surface coating based on amide functionalities, converting the hydrophobic membrane surface (water contact angle, WCA: ~90°) into an extremely hydrophilic one (WCA: ~30°). The amide layer was created by first immobilizing piperazine to the membrane surface via electron beam irradiation. Subsequently, a reaction with 1,3,5-benzenetricarbonyl trichloride (TMC) was applied to generate an amide structure. The presented approach resulted in a hydrophilic membrane surface, while maintaining permeance of the membrane without pore blocking. All membranes were investigated regarding their permeance, porosity, average pore size, morphology (SEM), chemical composition (XPS), and wettability. Soxhlet extraction was carried out to demonstrate the stability of the applied coating. The improvement of the modified membranes was demonstrated using dead-end filtration of algae solutions. After three fouling cycles, about 60% of the initial permeance remain for the modified membranes, while only ~25% remain for the reference.

scholarly journals Fabrication of Bentonite–Silica Sand/Suspended Waste Palm Leaf Composite Membrane for Water Purification

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 290
Author(s):  
Saad A. Aljlil
Keyword(s):  
Contact Angle ◽  
Pore Size ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Ceramic Membranes ◽  
Suspended Solid ◽  
Silica Sand ◽  
Distribution Analysis ◽  
Average Pore ◽  
Water Contact

In this study, a method for fabricating tubular ceramic membranes via extrusion using economical and locally available bentonite–silica sand and waste palm leaves was developed as a tool for conducting the necessary task of purifying water polluted with oil and suspended solid materials produced via various industrial processes. The developed tubular ceramic membranes were found to be highly efficient at separating the pollutants from water. The properties of the fabricated membrane were evaluated via mechanical testing, pore size distribution analysis, and contact angle measurements. The water contact angle of the fabricated membrane was determined to be 55.5°, which indicates that the membrane surface is hydrophilic, and the average pore size was found to be 66 nm. The membrane was found to demonstrate excellent corrosion resistance under acidic as well as basic conditions, with weight losses of less than 1% in each case. The membrane surface was found to be negatively charged and it could strongly repulse the negatively charged fine bentonite particles and oil droplets suspended in the water, thereby enabling facile purification through backwashing. The obtained ceramic membranes with desirable hydrophilic properties can thus serve as good candidates for use in ultrafiltration processes.

Study of Backwashing Process for Ceramic Micro-Filtration Membranes Used in Pretreatment of DMF Wastewater

2011 ◽  
Vol 418-420 ◽  
pp. 1980-1983
Author(s):  
Peng Wei Xu ◽  
Wei Qiu Huang ◽  
Qi Zhang ◽  
Bao Zhu Yang ◽  
Jing Zhong
Keyword(s):  
Membrane Fouling ◽  
Reverse Flow ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Permeate Flux ◽  
Average Pore ◽  
Filtration Membranes ◽  
Membrane Flux ◽  
In Series ◽  
Flow Through

DMF wastewater from the PU synthetic leather industries was filtrated by ZrO2 micro-filtration membranes with an average pore size of 0.2μm. The membrane fouling mechanism was analyzed by resistance-in series model. The results indicated that the resistance from the particles sedimentation on membrane surface accounting for 76% of the total resistances. The technology of backwashing was a stable, valid and reusable method to recover the membrane flux in the micro-filtration. During backwashing, the reverse flow through the membrane removes the concentration polarization and cake or gel layers from the membrane surface. The effect of the backwashing conditions on the flux was studied. The obtained optimization conditions were as follows: backwashing pressure 0.6 MPa, backwashing time 5s and the backwashing interval 20min. The permeate flux could be raised about 50% compared with that without backwashing.

scholarly journals A Review of Membrane Distillation Process: Before, During and After Testing

2019 ◽  
Vol 6 (1) ◽  
pp. 62-81
Author(s):  
N.A.S. Muhamad ◽  
Nadzirah Mohd Mokhtar ◽  
R. Naim ◽  
W.J. Lau ◽  
A.F. Ismail
Keyword(s):  
Membrane Fouling ◽  
Treatment Process ◽  
Membrane Distillation ◽  
Separation And Purification ◽  
Hydrophobic Membrane ◽  
Major Drawback ◽  
Membrane Performance ◽  
Membrane Surfaces ◽  
Thermally Driven ◽  
Pass Through

Membrane Distillation (MD) is a promising technology for separation and purification processes. It is a thermally-driven separation process which allow only vapour molecules are to pass through a porous hydrophobic membrane. MD separation is driven by the vapour pressure difference existing between the porous hydrophobic membrane surfaces unlike normal membrane processes which operate on temperature difference. This paper focus on the expectation of MD treatment process primarily for the readers who have no idea about this membrane process A brief overview is given of MD before treatment process which includes membrane materials, membrane preparation techniques, membrane characteristics, module and configuration. Membrane performance during treatment process will be highlighted. Membrane fouling which is one of the major drawback of MD will be also discussed.

scholarly journals Analysis of Superhydrophobic-Superoleophilic Properties on Modification of Polyurethane Sponge for Selective Oil-Water Separation

2021 ◽  
Vol 4 (1) ◽  
pp. 52-62
Author(s):  
Niken Aprilia Eka Putri ◽  
Arif Tjahjono ◽  
Perdamean Sebayang
Keyword(s):  
Separation Efficiency ◽  
Average Pore Size ◽  
Dip Coating ◽  
Absorption Capacity ◽  
Average Pore ◽  
Water Contact ◽  
Water Separation ◽  
Coating Methods ◽  
Oil Water Separation ◽  
Polyurethane Sponge

In this research, a modification of polyurethane (PU) sponge material has been made to obtain superhydrophobic-superoleophilic properties. The PU sponge was coated with several nanomaterials such as ZnO, Fe3O4+TEOS, and stearic acid by dip-coating and drop-coating methods. The tests include selective separation of oil and water with a magnetic response. Several types of oil and organic solvents were tested for absorption capacity. The results showed that the PU@ZnO@Fe3O4@SA sponge has a good absorption capacity, from 4.37 mL to 7.37 mL. The fabricated PU sponge could selectively separate oil from water with a separation efficiency above 99%. The fabricated PU sponge also could be magnetically driven by external magnetic fields. From the characterization using 3D OM, the water contact angle was 153.38°, which indicates that the PU@ZnO@Fe3O4@SA sponge is superhydrophobic. And from surface morphology obtained an average pore size diameter of 167.475 μm.

Novel Membrane Suitable for Membrane Distillation: Effect of Mixed Nanofillers on the Membrane Performance

2019 ◽  
Vol 801 ◽  
pp. 325-330 ◽  
Author(s):  
Mohamed R. El-Marghany ◽  
Ahmed H. El-Shazly ◽  
Mohamed Sameh Abdalghany Salem ◽  
Mohamed Nabil Sabry ◽  
Norhan Nady
Keyword(s):  
Sodium Chloride ◽  
Vinylidene Fluoride ◽  
Chloride Concentration ◽  
Membrane Distillation ◽  
Polymeric Membrane ◽  
Sodium Chloride Concentration ◽  
Electrospinning Technique ◽  
Average Pore ◽  
Water Contact ◽  
Membrane Performance

The aim of the present work is to investigate the performance of a newly fabricated membrane used for the membrane distillation process. Both titanium dioxide nanorods and multi-walled carbon nanotubes together were dispersed inside Poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membrane. Both pure PVDF-HFP and its composite membrane with the two fillers together PVDF-HFP/TiO2-CNTs were fabricated using electrospinning technique and were imaged by using SEM. Both the fiber diameter and the average pore diameter were calculated by using ImageJ software. Static water contact angle, membrane porosity, liquid enter pressure were determined. Moreover, the membrane performance was determined by using membrane distillation (MD) system for desalination. The effect of the feed conditions such as feed temperature, flow rate, and salt concentration, were studied. The obtained results confirm the improvement in the membrane productivity up to 46% at 9000 ppm sodium chloride concentration and by about 13.7% than the pure polymeric membrane at the highest used feed sodium chloride concentration (36000 ppm).

scholarly journals Development of Polysulfone Membrane via Vapor-Induced Phase Separation for Oil/Water Emulsion Filtration

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2519
Author(s):  
Nafiu Umar Barambu ◽  
Muhammad Roil Bilad ◽  
Mohamad Azmi Bustam ◽  
Nurul Huda ◽  
Juhana Jaafar ◽  
...  
Keyword(s):  
Phase Separation ◽  
Surface Chemistry ◽  
Exposure Time ◽  
Membrane Fouling ◽  
Membrane Structure ◽  
Membrane Surface ◽  
Hydrophobic Membrane ◽  
Polysulfone Membrane ◽  
Water Emulsion ◽  
Oil Water

The discharge of improperly treated oil/water emulsion by industries imposes detrimental effects on human health and the environment. The membrane process is a promising technology for oil/water emulsion treatment. However, it faces the challenge of being maintaining due to membrane fouling. It occurs as a result of the strong interaction between the hydrophobic oil droplets and the hydrophobic membrane surface. This issue has attracted research interest in developing the membrane material that possesses high hydraulic and fouling resistance performances. This research explores the vapor-induced phase separation (VIPS) method for the fabrication of a hydrophilic polysulfone (PSF) membrane with the presence of polyethylene glycol (PEG) as the additive for the treatment of oil/water emulsion. Results show that the slow nonsolvent intake in VIPS greatly influences the resulting membrane structure that allows the higher retention of the additive within the membrane matrix. By extending the exposure time of the cast film under humid air, both surface chemistry and morphology of the resulting membrane can be enhanced. By extending the exposure time from 0 to 60 s, the water contact angle decreases from 70.28 ± 0.61° to 57.72 ± 0.61°, and the clean water permeability increases from 328.70 ± 8.27 to 501.89 ± 8.92 (L·m−2·h−1·bar−1). Moreover, the oil rejection also improves from 85.06 ± 1.6 to 98.48 ± 1.2%. The membrane structure was transformed from a porous top layer with a finger-like macrovoid sub-structure to a relatively thick top layer with a sponge-like macrovoid-free sub-structure. Overall results demonstrate the potential of the VIPS process to enhance both surface chemistry and morphology of the PSF membrane.

scholarly journals Effect of Initial Water Flux on the Performance of Anaerobic Membrane Bioreactor: Constant Flux Mode versus Varying Flux Mode

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 203
Author(s):  
Xiawen Yi ◽  
Meng Zhang ◽  
Weilong Song ◽  
Xinhua Wang
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Water Flux ◽  
Operating Time ◽  
Operating Mode ◽  
Initial Water ◽  
Constant Flux ◽  
Membrane Performance ◽  
Fouling Mitigation ◽  
Flux Mode

Anaerobic membrane bioreactors (AnMBRs) have aroused growing interest in wastewater treatment and energy recovery. However, serious membrane fouling remains a critical hindrance to AnMBRs. Here, a novel membrane fouling mitigation via optimizing initial water flux is proposed, and its feasibility was evaluated by comparing the membrane performance in AnMBRs between constant flux and varying flux modes. Results indicated that, compared with the constant flux mode, varying flux mode significantly prolonged the membrane operating time by mitigating membrane fouling. Through the analyses of fouled membranes under two operating modes, the mechanism of membrane fouling mitigation was revealed as follows: A low water flux was applied in stage 1 which slowed down the interaction between foulants and membrane surface, especially reduced the deposition of proteins on the membrane surface and formed a thin and loose fouling layer. Correspondingly, the interaction between foulants was weakened in the following stage 2 with a high water flux and, subsequently, the foulants absorbed on the membrane surface was further reduced. In addition, flux operating mode had no impact on the contaminant removal in an AnMBR. This study provides a new way of improving membrane performance in AnMBRs via a varying flux operating mode.

scholarly journals Effect of the Zwitterion, p(MAO-DMPA), on the Internal Structure, Fouling Characteristics, and Dye Rejection Mechanism of PVDF Membranes

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 323
Author(s):  
Nelisa Ncumisa Gaxela ◽  
Philiswa Nosizo Nomngongo ◽  
Richard Motlhaletsi Moutloali
Keyword(s):  
Internal Structure ◽  
Membrane Fouling ◽  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Proton Nuclear Magnetic Resonance ◽  
Pvdf Membrane ◽  
Membrane Performance ◽  
Dye Rejection

The zwitterion poly-(maleic anhydride-alt-1-octadecene-3-(dimethylamino)-1-propylamine) (p(MAO-DMPA)) synthesized using a ring-opening reaction was used as a poly(vinylidene fluoride) (PVDF) membrane modifier/additive during phase inversion process. The zwitterion was characterized using proton nuclear magnetic resonance (1HNMR) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Atomic force microscopy (AFM), field emission scanning electron microscope (SEM), FTIR, and contact angle measurements were taken for the membranes. The effect of the zwitterionization content on membrane performance indicators such as pure water flux, membrane fouling, and dye rejection was investigated. The morphology of the membranes showed that the increase in the zwitterion amount led to a general decrease in pore size with a concomitant increase in the number of membrane surface pores. The surface roughness was not particularly affected by the amount of the additive; however, the internal structure was greatly influenced, leading to varying rejection mechanisms for the larger dye molecule. On the other hand, the wettability of the membranes initially decreased with increasing content to a certain point and then increased as the membrane homogeneity changed at higher zwitterion percentages. Flux and fouling properties were enhanced through the addition of zwitterion compared to the pristine PVDF membrane. The high (>90%) rejection of anionic dye, Congo red, indicated that these membranes behaved as ultrafiltration (UF). In comparison, the cationic dye, rhodamine 6G, was only rejected to <70%, with rejection being predominantly electrostatic-based. This work shows that zwitterion addition imparted good membrane performance to PVDF membranes up to an optimum content whereby membrane homogeneity was compromised, leading to poor performance at its higher loading.

scholarly journals Electrospun Polycaprolactone Nanofibers as a Reaction Membrane for Lateral Flow Assay

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1387 ◽  
Author(s):  
Chee Yew ◽  
Pedram Azari ◽  
Jane Choi ◽  
Farina Muhamad ◽  
Belinda Pingguan-Murphy
Keyword(s):  
Flow Rate ◽  
Point Of Care ◽  
Low Cost ◽  
Average Pore Size ◽  
Lateral Flow ◽  
Detection Sensitivity ◽  
Average Pore ◽  
Water Contact ◽  
Naoh Solution ◽  
Lateral Flow Assays

Electrospun polycaprolactone (PCL) nanofibers have emerged as a promising material in diverse biomedical applications due to their various favorable features. However, their application in the field of biosensors such as point-of-care lateral flow assays (LFA) has not been investigated. The present study demonstrates the use of electrospun PCL nanofibers as a reaction membrane for LFA. Electrospun PCL nanofibers were treated with NaOH solution for different concentrations and durations to achieve a desirable flow rate and optimum detection sensitivity in nucleic acid-based LFA. It was observed that the concentration of NaOH does not affect the physical properties of nanofibers, including average fiber diameter, average pore size and porosity. However, interestingly, a significant reduction of the water contact angle was observed due to the generation of hydroxyl and carboxyl groups on the nanofibers, which increased their hydrophilicity. The optimally treated nanofibers were able to detect synthetic Zika viral DNA (as a model analyte) sensitively with a detection limit of 0.5 nM. Collectively, the benefits such as low-cost of fabrication, ease of modification, porous nanofibrous structures and tunability of flow rate make PCL nanofibers a versatile alternative to nitrocellulose membrane in LFA applications. This material offers tremendous potential for a broad range of point-of-care applications.

scholarly journals Fabrication and Characterization of GO-Fe3O4/PSF Membrane with Phase Inversion Method

2021 ◽  
Vol 6 (2) ◽  
pp. 55-60
Author(s):  
Vivia Maulida Alfianti ◽  
◽  
Munasir Munasir ◽  
Keyword(s):  
Phase Inversion ◽  
Average Pore Size ◽  
Membrane Surface ◽  
Xrd Analysis ◽  
Solid Matrix ◽  
Coagulation Bath ◽  
Inversion Method ◽  
Average Pore ◽  
Polysulfone Membrane ◽  
Phase Inversion Method

Polysulfones are hydrophobic which can reduce membrane permeability. Permeability can be increased through the application of hydrophilic materials such as GO-Fe3O4 to the polysulfone membrane so that the membrane is hydrophilic. The riset purpose to determine the effect of the percentage weight of different material compositions on the hydrophilicity properties of the polysulfone membrane. Membrane fabrication is carried out using the phase inversion method where the polymer solution is molded in a place and immersed in a coagulation bath containing non-solvent. This solvent exchange causes the polymer to form a solid matrix and become a membrane. The results showed that GO particles were successfully doped with Fe3O4 material shown by XRD analysis at a peak of 35.61˚ with a magnetite phase, while FTIR analysis showed that there was an absorption band characteristic of Fe-O streching vibrations. The results of the contact angle test on the GO-Fe3O4/PSF membrane 0.75 wt per cent were around 73.17˚ which showed the smallest hydrophobic value and the membrane surface morphology had an average pore size of 333.61 nm so that the addition of GO-Fe3O4 composites could increase membrane hydrophilicity.

Sign in / Sign up

Export Citation Format

Share Document