scholarly journals Fast and Versatile Pathway in Fabrication of Polyelectrolyte Multilayer Nanofiltration Membrane with Tunable Properties

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Ahmad M. Alghamdi

Thin film composite nanofiltration (NF) membranes are relatively new membranes compared to other types of pressure-driven membranes. However, they attract interest from researchers due to their versatility to be used in various applications. In this work, a new class of NF membrane was successfully fabricated through spin-assisted layer-by-layer assembly by depositing alternate layers of branched polyethylenimine (PEI) and poly(sodium 4-styrenesulfonate) (PSS) on ultrafiltration polysulfone (PSF) membrane. The suitability of the fabricated membranes for removal of divalent ions was investigated. It was found that the membrane consisting of (PEI/PSS)10–0.05 M NaCl showed MgCl2 rejection rate of 93.95% and permeation flux of 0.9 L/m2·h bar during tests performed using a crossflow permeation cell at a crossflow velocity of 0.65 m/s, MgCl2 feed concentration of 6530 ppm, pressure of 10 bar, temperature of 32.5°C, and pH of 6.5. This result suggests that this new fabrication method is suitable for producing polyelectrolyte multilayered (PEM) NF membranes that exhibit comparable membrane performance to commercial ones.


2020 ◽  
Vol 5 (1) ◽  
pp. 10-15
Author(s):  
Ahmad Alghamdi ◽  
Farid Fadhillah

Thin Film Composite (TFC) Polyelectrolyte Multilayer (PEM) Nanofiltration (NF) membrane consisting of multilayer of Poly(diallyl dimethyl ammonium chloride) (PDAC) and Poly(sodium 4-styrenesulfonate) (PSS) deposited on  polyethersulfone (PES) support  was prepared using spin-assisted layer by layer assembly (SA-LbL). This work is an effort to discover new material having better characteristics and performance than commercial polyamide (PA) NF membrane. Two main operating conditions namely temperature and salt concentration were investigated and the effect of both on membrane performance was studied. Solution-diffusion Film Model (SDFM) membrane employing two fitting parameters i.e. membrane salt permeability (PS) and stagnant layer salt permeability PS(d), was used to explain membrane transport across the membrane. The result showed an good agreement between experimental and observed rejection rate suggests PEM membrane behaves similar to typical solution diffusion-type  composite membrane and SDFM can be used to predict the membrane performance and behavior.



Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 137
Author(s):  
Hongyi Han ◽  
Ruobin Dai ◽  
Zhiwei Wang

Widespread applications of nanofiltration (NF) and reverse osmosis (RO)-based processes for water purification and desalination call for high-performance thin-film composite (TFC) membranes. In this work, a novel and facile modification method was proposed to fabricate high-performance thin-film composite nanofiltration membrane by introducing Ca2+ in the heat post-treatment. The introduction of Ca2+ induced in situ Ca2+-carboxyl intra-bridging, leading to the embedment of Ca2+ in the polyamide (PA) layer. This post modification enhanced the hydrophilicity and surface charge of NF membranes compared to the pristine membrane. More interestingly, the modified membrane had more nodules and exhibited rougher morphology. Such changes brought by the addition of Ca2+ enabled the significant increase of water permeability (increasing from 17.9 L·m−2·h−1·bar−1 to 29.8 L·m−2·h−1·bar−1) while maintaining a high selectivity (Na2SO4 rejection rate of 98.0%). Furthermore, the intra-bridging between calcium and carboxyl imparted the NF membranes with evident antifouling properties, exhibiting milder permeability decline of 4.2% (compared to 16.7% of NF-control) during filtration of sodium alginate solution. The results highlight the potential of using Ca2+-carboxyl intra-bridging post-treatment to fabricate high-performance TFC membranes for water purification and desalination.



2017 ◽  
Vol 79 (1-2) ◽  
Author(s):  
Nur Syazwana Hasmadi ◽  
Nora Jullok ◽  
Al Nazifah Mat Razi ◽  
M. Hanif Harif Fadzilah

Reverse osmosis (RO) often used for desalination, in producing the ultrapure water for electronics, pharmaceuticals and power generation industries and also it was used in small niche process such as food processing and pollution control. Analysis of membrane performance required multiple of experimental run. Experimental work can be time consuming and costly. Hence, this work aims to model a small scale RO system by using a solution-diffusion model to minimize the experimental work. The model was verified by comparing the data obtained from the model and experimental data. Other studies, which include, the influence of solute feed concentration on the RO system was also been investigated. A commercial RO Trisep flat sheet membrane  was used. The solute permeate concentrations, solvent permeate flux, final solute feed concentrations and rejection rate of sodium chloride (NaCl) was analyzed to observe the membrane performance. Result shows that some experimental data has almost similar trend with the simulated data. Both solute feed concentration and rejection rate of NaCl over time show almost similar trends with percentage errors are 8.89% and 0.76% respectively. As solute feed concentration increased, the solute permeate concentration increased. In contrast to the solute permeate concentration, when the solute feed increases the solvent permeate flux decreases and rejection rate will also decrease. 



Soft Matter ◽  
2021 ◽  
Author(s):  
Suprakash Samanta ◽  
Rashmi Ranjan Sahoo

Present study demonstrates a simple and multistep approach for the preparation of covalent functionalization of chemically prepared graphene oxide (GO) by branched polyethylenimine (PEI) through nucleophilic addition reaction to prepare...





2017 ◽  
Vol 407 ◽  
pp. 260-275 ◽  
Author(s):  
Hongbin Li ◽  
Wenying Shi ◽  
Qiyun Du ◽  
Rong Zhou ◽  
Haixia Zhang ◽  
...  


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