scholarly journals Construction of Loose Positively Charged NF Membrane by Layer-by-Layer Grafting of Polyphenol and Polyethyleneimine on the PES/Fe Substrate for Dye/Salt Separation

Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 699
Author(s):  
Shuai Liu ◽  
Xiaofeng Fang ◽  
Mengmeng Lou ◽  
Yihan Qi ◽  
Ruo Li ◽  
...  

The effective separation of dyes and inorganic salts is highly desirable for recycling inorganic salts and water resource in printing and dyeing wastewater treatment. In this work, tannic acid (TA) and polyethyleneimine (PEI) were grafted on the PES/Fe ultrafiltration membrane via the coordination assembly and Michael addition strategy to fabricated a loose nanofiltration membrane (LNM). The effect of PEI concentration on membrane morphologies and properties was systematically investigated. The membrane surface becomes more hydrophilic and transforms into positive charge after the PEI grafting. The optimized PES/Fe-TA-PEI membrane possesses high pure water flux (124.6 L·m−2·h−1) and excellent dye rejections (98.5%, 99.8%, 98.4%, and 86.4% for Congo red, Eriochrome black T, Alcian blue 8GX, and Bromophenol blue, respectively) under 2 bar operation pressure. Meanwhile, the LNM showed a high Alcian blue 8GX rejection (>98.4%) and low NaCl rejection (<5.3%) for the dye/salt mixed solutions separation. Moreover, the PES/Fe-TA-PEI LNM exhibited good antifouling performance and long-term performance stability. These results reveal that such LNM shows great potential for effective fractionation of dyes and salts and recycling of textile wastewater.

2018 ◽  
Vol 18 (1) ◽  
pp. 1
Author(s):  
Romaya Sitha Silitonga ◽  
Nurul Widiastuti ◽  
Juhana Jaafar ◽  
Ahmad Fauzi Ismail ◽  
Muhammad Nidzhom Zainol Abidin ◽  
...  

Poly(vinylidene fluoride) (PVDF) has outstanding properties such as high thermal stability, resistance to acid solvents and good mechanical strength. Due to its properties, PVDF is widely used as a membrane matrix. However, PVDF membrane is hydrophobic properties, so as for specific applications, the surface of membrane needs to be modified to become hydrophilic. This research aims to modify PVDF membrane surface with chitosan and glutaraldehyde as a crosslinker agent. The FTIR spectra showed that the modified membrane has a peak at 1655 cm-1, indicating the imine group (–N=C)- that was formed due to the crosslink between amine group from chitosan and aldehyde group from glutaraldehyde. Results showed that the contact angle of the modified membrane decreases to 77.22° indicated that the membrane hydrophilic properties (< 90°) were enhanced. Prior to the modification, the contact angle of the PVDF membrane was 90.24°, which shows hydrophobic properties (> 90°). The results of porosity, Ɛ (%) for unmodified PVDF membrane was 55.39%, while the modified PVDF membrane has a porosity of 81.99%. Similarly, by modifying the PVDF membrane, pure water flux increased from 0.9867 L/m2h to 1.1253 L/m2h. The enhancement of porosity and pure water flux for the modified PVDF membrane was due to the improved surface hydrophilicity of PVDF membrane.


2014 ◽  
Vol 789 ◽  
pp. 201-204
Author(s):  
Ai Wen Qin ◽  
Xiang Li ◽  
Bo Mou Ma ◽  
Xin Zhen Zhao ◽  
Chun Yi Liu ◽  
...  

Poly (vinylidene fluoride) (PVDF) hybrid membranes reinforced by hydrophilic nanoSiO2 particles were fabricated from PVDF/N-dimethylacetamide (DMAc)/γ-butyrolactone (γ-BL) system via thermally induced phase separation (TIPS) process. Surface and cross-sectional morphology of membranes were characterized by scanning electron microscope (SEM). The properties such as permeability, mechanical performances and antifouling property were also determined. The results showed that the pore size of membrane surface became smaller, while cross-sectional morphology was changed from bicontinuous structure to cell structure, the pore size became larger and majorities of closed pores became open with the addition of hydrophilic nanoSiO2 particles in the system. Compared with pure membrane, pure water flux of hybrid membrane increased by 30.3%, i.e. from 290 to 378 L/(m2·h·0.1MPa), antifouling property increased from 63.1% to 80.2%. Meanwhile, tensile strength and elongation at break increased by 70.6% and124%, respectively.


2019 ◽  
Vol 9 (1) ◽  
pp. 3744-3749
Author(s):  
H. Waheed ◽  
A. Hussain

Polyvinyl pyrolidone (PVP) was added as filler in cellulose acetate (CA) to produce mixed matrix membrane (MMM) for hemodialysis operation. Phase separation induced by diffusion (DIPS) was used for fabrication of mixed matrix CA/PVP flat sheet membranes. The effect of adding PVP was investigated on the morphology and permeation efficiencies of CA membranes. The surface arrangement of polymer and additives in pure and blended membrane was studied by FTIR, contact angle and SEM. Results revealed homogenous and significant mixing of PVP content into pure CA matrix. Performance efficiency of blended membranes was investigated by means of pure water flux (PWF), urea clearance and % rejection of bovine serum albumin (BSA). The observable decrease of contact angle from 83° to 69° in CA/PVP MMM membranes of varying composition effectively revealed enhancement in hydrophilicity of MMM membrane surface. For protein rejection, all CA/PVP membranes rejected>90% of BSA relative to 25% for pure CA membrane. Furthermore, urea clearance behavior for CA/PVP membranes was 62.4% in comparison to 52% for pure CA membrane. The incorporation PVP i.e 1% by weight (Mpvp1) significantly improved the hydrophilicity, PWF, BSA rejection and urea clearance percentages of modified CA membrane for dialysis application.


2018 ◽  
Vol 65 ◽  
pp. 05023 ◽  
Author(s):  
Kok Poh Wai ◽  
Chai Hoon Koo ◽  
Yean Ling Pang ◽  
Woon Chan Chong ◽  
Woei Jye Lau

Silver nanoparticles (NP) was successfully immobilized on polydopamine (PDA) supported polyethersulfone (PES) membrane via a redox reaction. Polyvinylpyrrolidone (PVP) was added into membrane dope solution as a pore-forming agent. Four pieces of membranes (M1, M2, M3 and M4) were fabricated with different active layer coatings to compare their morphological and performance properties. The differences between each sample were highlighted as follow: M1 (pristine PES), M2 (PES+PVP), M3 (PDA/PES+PVP) and M4 (Ag/PDA/PES+PVP). All membranes were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction and contact angle analysis. The membrane performance was examined using pure water permeability (PWP) test, antibacterial test and humic acid (HA) rejection test. Pristine M1 membrane showed that PWP of 27.16 LMH/bar and HA rejection of 84 %. In this study, it was found that the addition of PVP as a pore agent into the membrane M2 increased water flux but slightly deteriorated HA rejection. Coating of PDA on M3 and immobilizing silver NP on M4 membrane surface have improved HA rejection but compromised PWP. The results showed that membrane M4 carried excellent antibacterial property and highest HA rejection among all fabricated membranes.


Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 323
Author(s):  
Nelisa Ncumisa Gaxela ◽  
Philiswa Nosizo Nomngongo ◽  
Richard Motlhaletsi Moutloali

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.


2019 ◽  
Vol 797 ◽  
pp. 13-19
Author(s):  
Mok Tze How ◽  
Mazrul Nizam Abu Seman

In this study, FO membrane was fabricated by Layer-by-Layer (LbL) coating technique using Poly (sodium 4-styrene-sulfonate)(PSS) and Poly (diallyl-dimethylammoniumchloride) (PDADMAC) as the active polyelectrolytes. Different concentrations of polyelectrolytes and deposition time of polyelectrolytes were investigated. The success of the coated layer was confirmed using ATR-FTIR and FESEM images. The membrane performance was determined by water flux and reverse solute diffusion (RSD) using pure water and 1.75M Na2SO4 as feed and draw solution, respectively. It was observed that the highest water flux, 6.76 L/ was recorded at the lowest polyelectrolytes concentration and longer deposition time. Meanwhile, the minimum RSD was achieved by the membrane fabricated at the longest deposition time and highest polyelectrolyte concentration.


Author(s):  
A. M. Vijesh ◽  
P. C. Shyma ◽  
V. Prakash ◽  
B. Garudachari

Nanofiltration membranes are gaining more importance in the field of water treatment especially in desalination plants. Hollow fibre membranes have been preferred over other membrane configurations due to their high membrane surface area to module volume, mechanical property and easy handling. In the present work, we prepared new type of polysulfone (PSf) composite hollow fibre membranes by blending PSf with polyvinylpyrrolidinone-nitrobenzene (PVPD) in different compositions. New membranes were fabricated using wet-jet phase inversion technique. The resultant composite membranes were characterized by various analytical techniques such as water contact angle, SEM, DSC, TG. Pure water flux of the membranes was measured using cross-flow filtration techniques. The study revealed that increased composition of PVPD in casting solution resulted in a highly porous membrane structure and the pure water flux of the membranes increases in the same order.


Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2003
Author(s):  
Afrillia Fahrina ◽  
Nasrul Arahman ◽  
Sri Mulyati ◽  
Sri Aprilia ◽  
Normi Izati Mat Nawi ◽  
...  

Biofouling on the membrane surface leads to performance deficiencies in membrane filtration. In this study, the application of ginger extract as a bio-based additive to enhance membrane antibiofouling properties was investigated. The extract was dispersed in a dimethyl acetamide (DMAc) solvent together with polyvinylidene fluoride (PVDF) to enhance biofouling resistance of the resulting membrane due to its antibiotic property. The concentrations of the ginger extract in the dope solution were varied in the range of 0–0.1 wt %. The antibacterial property of the resulting membranes was assessed using the Kirby Bauer disc diffusion method. The results show an inhibition zone formed around the PVDF/ginger membrane against Escherichia coli and Staphylococcus aureus demonstrating the efficacy of the residual ginger extract in the membrane matrix to impose the antibiofouling property. The addition of the ginger extract also enhanced the hydrophilicity in the membrane surface by lowering the contact angle from 93° to 85°, which was in good agreement with the increase in the pure water flux of up to 62%.


2011 ◽  
Vol 121-126 ◽  
pp. 387-391
Author(s):  
Guo Lan Huan ◽  
Jian Li Liu ◽  
Qi Yun Du ◽  
Xiao Yu Hu

Polyvinylidene fluoride/polyurethane (PVDF/PU) blend membranes were made via immersion precipitation process, the surface morphologies and the micro-porous structures of the blend membranes were analyzed using scanning electronic microscope (SEM) and fractal theory, the water flux change with the operation pressure of the blend membranes was investigated, and the relationship between blend membrane morphology and water flux was discussed. The results showed that, the water flux of the resulting blend membranes was increased, and the contribution of different structures to water flux was in the following order: cross-section finger-shaped porous defects > cross-section through holes > blend membrane surface pores. In addition, water flux of the blend membranes was also related to the deformability of PU.


2021 ◽  
Vol 45 (1) ◽  
pp. 1-10
Author(s):  
Davood Ghanbari ◽  
Samaneh BandehAli ◽  
Abdolreza Moghadassi

Abstract In this study, three types of ferrites nanoparticles including CoFe2O4, NiFe2O4, and ZnFe2O4 were synthesized by microwave-assisted hydrothermal method. The X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM) were employed to analyze synthesized nanoparticles and fabricated membranes. The morphology of membrane surface was investigated by surface images. The ability of ferrite nanoparticles was evaluated to the separation of sodium salt and heavy metals such as Cr2+, Pb2+, and Cu2+ from aqueous solutions. The modified membrane showed the enhancement of membrane surface hydrophilicity, porosity, and mean pore size. The results revealed a significant increase in pure water flux: 152.27, 178, and 172.68 L·m−2·h−1 for PES/0.001 wt% of CoFe2O4, PES/0.001 wt% NiFe2O4, and PES/0.001 wt% ZnFe2O4 NPs, respectively. Moreover, Na2SO4 rejection was reached 78% at 0.1 wt% of CoFe2O4 NPs. The highest Cr (II) rejection obtained 72% for PES/0.001 wt% of NiFe2O4 NPs while it was 46% for the neat PES membrane. The Pb(II) rejection reached above 75% at 0.1 wt% of CoFe2O4 NPs. The Cu(II) rejection was obtained 75% at 0.1 wt% of CoFe2O4 NPs. The ferrite NPs revealed the high potential of heavy metal removal in the filtration membranes.


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