Enhancement of the Donnan effect through capacitive ion increase using an electroconductive rGO-CNT nanofiltration membrane

2018 ◽  
Vol 6 (11) ◽  
pp. 4737-4745 ◽  
Author(s):  
Chengzhi Hu ◽  
Zhongtao Liu ◽  
Xinglin Lu ◽  
Jingqiu Sun ◽  
Huijuan Liu ◽  
...  
Keyword(s):  
Nanofiltration Membrane ◽  
Salt Rejection ◽  
Donnan Effect ◽  
Electrochemical Assistance

Enhanced Donnan repulsion through increase in capacitive ions contributes to the remarkable salt rejection ability of the GCM under electrochemical assistance.

Transport coefficients and cadmium salt rejection in nanofiltration membrane

Desalination ◽  
2004 ◽  
Vol 167 ◽  
pp. 369-376 ◽  
Author(s):  
Guy Tiama Ballet ◽  
Lassaad Gzara ◽  
Amor Hafiane ◽  
M. Dhahbi
Keyword(s):  
Transport Coefficients ◽  
Nanofiltration Membrane ◽  
Salt Rejection ◽  
Cadmium Salt

scholarly journals Development of polyethersulfone (PES)/reduced graphene oxide nanocomposite nanofiltration membrane

2020 ◽  
Vol 16 (4) ◽  
pp. 418-421
Author(s):  
Norzakiah Hamzah ◽  
Fasihah Johary ◽  
Rosiah Rohani ◽  
Syazrin Syima Sharifuddin ◽  
Mohd Hafez Mohd Isa
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Pure Water ◽  
Inversion Method ◽  
Nanofiltration Membrane ◽  
Membrane Pore ◽  
Water Permeation ◽  
Salt Rejection ◽  
Casting Solution ◽  
Reduced Graphene

Polyethersulfone (PES) is a polymeric material that is commonly used due to its chemical resistance, high mechanical strength, and thermal stability. The improvement of PES hydrophilicity and anti-fouling properties can be facilitated by mixing additives into the polymer casting solution. This study involved the preparation and characterization of PES/pluronic F108/chitosan/reduced graphene oxide (rGO) nanocomposite nanofiltration membrane. The modified PES membrane was developed by employing the phase inversion method via immersion precipitation. The effect of varying concentration of rGO nanocomposite ranging from 0.05 to 0.20 wt% in the fabricated membrane was evaluated in terms of membrane pure water permeation (PWP), salt rejection, morphology, and hydrophilicity. Images obtained from scanning electron microscopy (SEM) showed increasing rGO nanocomposite concentration in the casting solution, resulted in the increase in membrane sub layer thickness, hydrophilicity, salt rejection, and improvement in the membrane pore structure. Fourier transform-infrared (FTIR) spectroscopy confirmed the presence of the hydrophilic functional group and chemical compound in the prepared membrane. PES with 0.20 wt% of rGO nanocomposite obtained the highest PWP at 28.64 (L/m2h) at 5 bar pressure, whereas the highest rejections of monovalent and multivalent salt were obtained by PES with 0.15 wt% rGO nanocomposite with 75% and 89% rejections, respectively at 5 bar pressure. This study shows that the utilization of rGO nanocomposite as an additive in the PES casting solution can enhance nanofiltration membrane performance and morphological structure.

scholarly journals Enhancing H2O2 Tolerance and Separation Performance through the Modification of the Polyamide Layer of a Thin-Film Composite Nanofiltration Membrane by Using Graphene

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 592
Author(s):  
Yi-Li Lin ◽  
Nai-Yun Zheng ◽  
Yu-Shen Chen
Keyword(s):  
Thin Film ◽  
Water Permeability ◽  
Interfacial Polymerization ◽  
Membrane Surface ◽  
Separation Performance ◽  
Nanofiltration Membrane ◽  
Permeate Flux ◽  
Film Composite ◽  
Salt Rejection ◽  
Thin Film Composite

Through interfacial polymerization (IP), a polyamide (PA) layer was synthesized on the top of a commercialized polysulfone substrate to form a thin-film composite (TFC) nanofiltration membrane. Graphene oxide (GO) was dosed during the IP process to modify the NF membrane, termed TFC-GO, to enhance oxidant resistance and membrane performance. TFC-GO exhibited increased surface hydrophilicity, water permeability, salt rejection, removal efficiency of pharmaceutical and personal care products (PPCPs), and H2O2 resistance compared with TFC. When H2O2 exposure was 0–96000 ppm-h, the surfaces of the TFC and TFC-GO membranes were damaged, and swelling was observed using scanning electron microscopy. However, the permeate flux of TFC-GO remained stable, with significantly higher NaCl, MgSO4, and PPCP rejection with increasing H2O2 exposure intensity than TFC, which exhibited a 3.5-fold flux increase with an approximate 50% decrease in salt and PPCP rejection. GO incorporated into a PA layer could react with oxidants to mitigate membrane surface damage and increase the negative charge on the membrane surface, resulting in the enhancement of the electrostatic repulsion of negatively charged PPCPs. This hypothesis was confirmed by the significant decrease in PPCP adsorption onto the surface of TFC-GO compared with TFC. Therefore, TFC-GO membranes exhibited superior water permeability, salt rejection, and PPCP rejection and satisfactory resistance to H2O2, indicating its great potential for practical applications.

CHARACTERIZATION STUDIES OF A NEW CERAMIC NANOFILTRATION MEMBRANE WITH FOULING RESISTANT PROPERTIES FOR EFFICIENT WATER TREATMENT

2016 ◽  
Vol 15 (7) ◽  
pp. 1629-1634
Author(s):  
Mihaela-Elena Dascalu ◽  
David Amaya Vias ◽  
Valentin Nedeff ◽  
Juan Antonio Lopez-Ramirez
Keyword(s):  
Water Treatment ◽  
Nanofiltration Membrane ◽  
Characterization Studies

scholarly journals Electrospun Nanostructured Membrane Engineering Using Reverse Osmosis Recycled Modules: Membrane Distillation Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1601
Author(s):  
Jorge Contreras-Martínez ◽  
Carmen García-Payo ◽  
Mohamed Khayet
Keyword(s):  
Reverse Osmosis ◽  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Electrospinning Technique ◽  
Salt Rejection ◽  
Rejection Factor ◽  
Nanofibrous Membranes ◽  
Membrane Engineering ◽  
Desalination Plants

As a consequence of the increase in reverse osmosis (RO) desalination plants, the number of discarded RO modules for 2020 was estimated to be 14.8 million annually. Currently, these discarded modules are disposed of in nearby landfills generating high volumes of waste. In order to extend their useful life, in this research study, we propose recycling and reusing the internal components of the discarded RO modules, membranes and spacers, in membrane engineering for membrane distillation (MD) technology. After passive cleaning with a sodium hypochlorite aqueous solution, these recycled components were reused as support for polyvinylidene fluoride nanofibrous membranes prepared by electrospinning technique. The prepared membranes were characterized by different techniques and, finally, tested in desalination of high saline solutions (brines) by direct contact membrane distillation (DCMD). The effect of the electrospinning time, which is the same as the thickness of the nanofibrous layer, was studied in order to optimize the permeate flux together with the salt rejection factor and to obtain robust membranes with stable DCMD desalination performance. When the recycled RO membrane or the permeate spacer were used as supports with 60 min electrospinning time, good permeate fluxes were achieved, 43.2 and 18.1 kg m−2 h−1, respectively; with very high salt rejection factors, greater than 99.99%. These results are reasonably competitive compared to other supported and unsupported MD nanofibrous membranes. In contrast, when using the feed spacer as support, inhomogeneous structures were observed on the electrospun nanofibrous layer due to the special characteristics of this spacer resulting in low salt rejection factors and mechanical properties of the electrospun nanofibrous membrane.

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