An attempt to enhance water flux of hollow fiber polyamide composite nanofiltration membrane by the incorporation of hydrophilic and compatible PPTA/PSF microparticles

2022 ◽  
Vol 280 ◽  
pp. 119821
Author(s):  
Wenying Shi ◽  
Tengfei Li ◽  
Hongbin Li ◽  
Qiyun Du ◽  
Haixia Zhang ◽  
...  
2012 ◽  
Vol 529 ◽  
pp. 569-573 ◽  
Author(s):  
Lei Wen ◽  
Wei Wang

Hollow fiber composite nanofiltration (NF) membranes were prepared by interfacial polymerization method, with polysulfone (PSF) hollow fiber ultrafiltration membrane as base membrane, piperazine (PIP) as the aqueous phase monomer and trimesoyl chloride (TMC) as the organic phase monomer. The effects of aqueous phase composition on composite NF were discussed. The experimental results show that the optimum compositions in aqueous phase: 1wt% PIP, 0.05wt% MPDA, 1wt% TEA, 3wt% sulfamic acid. The best rejection to MgSO4 was 94.7%, and water flux was 66.1L•m-2•h-1.


2012 ◽  
Vol 65 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Jianmian Deng ◽  
Yatao Zhang ◽  
Jindun Liu ◽  
Haoqin Zhang

Three-bore hollow fiber charged nanofiltration (NF) membrane was prepared by interfacial polymerization (IP). The results showed that the flux and rejection of NF membrane prepared in this study increased with the increasing in the operating pressure. The water flux decreased and rejection for obvious dyes increased as the solute concentration increased. The separation factor for mixture of Xylenol orange/NaCl decreased when NaCl concentration in solution increased and could reach to as high as 18. In addition, three-bore hollow fiber charged nanofiltration membrane prepared in this study has excellent stability for strong acid (pH = 3), strong alkali (pH = 11) and high temperature solution (80 °C).


2011 ◽  
Vol 480-481 ◽  
pp. 201-206
Author(s):  
Li Guo Wang ◽  
Xiu Ju Wang ◽  
Ai Min Wang ◽  
Wen Juan Liu ◽  
Shi Qi Guo ◽  
...  

Hydrophilic Polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration membranes were prepared by wet-spinning method. The effects of technical parameters of acrylic acid grafted onto PVDF on the performance of hydrophilic PVDF membranes were investigated via orthogonal test, the technical parameters of preparation of hydrophilic PVDF membranes were determined, and hydrophilic PVDF membranes were prepared. Then hydrophilic PVDF membranes were characterized in terms of breaking strength, breaking elongation, rupture pressure, pure water flux and rejection. The fouling properties and the conditions of acrylic acid grafted onto PVDF were also examined. The results showed that acrylic acid had been grafted onto PVDF, the breaking strength and rupture pressure improved greatly, and the fouling properties were better than PS hollow fiber UF membrane.


2021 ◽  
Vol 118 (37) ◽  
pp. e2019891118
Author(s):  
Yang Lu ◽  
Ruoyu Wang ◽  
Yuzhang Zhu ◽  
Zhenyi Wang ◽  
Wangxi Fang ◽  
...  

In this study, we report the emergence of two-dimensional (2D) branching fractal structures (BFS) in the nanoconfinement between the active and the support layer of a thin-film-composite polyamide (TFC-PA) nanofiltration membrane. These BFS are crystal dendrites of NaCl formed when salts are either added to the piperazine solution during the interfacial polymerization process or introduced to the nascently formed TFC-PA membrane before drying. The NaCl dosing concentration and the curing temperature have an impact on the size of the BFS but not on the fractal dimension (∼1.76). The BFS can be removed from the TFC-PA membranes by simply dissolving the crystal dendrites in deionized water, and the resulting TFC-PA membranes have substantially higher water fluxes (three- to fourfold) without compromised solute rejection. The flux enhancement is believed to be attributable to the distributed reduction in physical binding between the PA active layer and the support layer, caused by the exertion of crystallization pressure when the BFS formed. This reduced physical binding leads to an increase in the effective area for water transport, which, in turn, results in higher water flux. The BFS-templating method, which includes the interesting characteristics of 2D crystal dendrites, represents a facile, low-cost, and highly practical method of enhancing the performance of the TFC-PA nanofiltration membrane without having to alter the existing infrastructure of membrane fabrication.


2020 ◽  
pp. 152808372096707
Author(s):  
Hongbin Li ◽  
Wenying Shi ◽  
Qiyun Du ◽  
Shoufa Huang ◽  
Haixia Zhang ◽  
...  

Although membrane distillation (MD) technology has the outstanding advantages of almost 100% solute retention and mild operation conditions, its further development is limited by low permeate flux. In order to solve the problem, the improvement of membrane hydrophobicity becomes one of the effective solutions. In this study, a loose and porous hydrophobic zeolitic imidazolate frameworks-71 (ZIF-71)/polyvinylidene fluoride (PVDF) coating layer was composited on the outside surface of PVDF hollow fiber support membrane by the dilute solution coating to enhance membrane hydrophobicity. The prepared hollow fiber composite (HFC) membranes were employed to remove high concentration Congo red (CR) through VMD. The effects of different operation conditions including the dye concentration, feed temperature, vacuum pressure and feed flow rate on CR rejection and permeate water flux were investigated. In the variation range of operating conditions, all the CR rejection of the PVDF HFC membranes shows a slight change and remains above 99.9%. Under the optimal operation conditions including dye concentration 600 mg·L−1, vacuum pressure 31.325 kPa, feed temperature 60°C and feed flow rate 50 L·h−1, HFC membrane exhibit a permeate water flux of 13.15 kg·m−2·h−1. HFC membrane suffers dye fouling during the continuous dye filtration for 100 h. The fouling mechanism was proposed and a combined cleaning way including forward washing, back flushing and chemical desorption has been proved to be effective in recovering membrane water flux.


2012 ◽  
Vol 152-154 ◽  
pp. 574-578 ◽  
Author(s):  
Ping Lan ◽  
Wei Wang

Polyethersulfone (PES) hollow fiber membranes have been widely used in many fields, such as ultrafiltration, microfiltration, reverse osmosis, liquid/liquid or liquid/solid separation, gas separation, hemodialysis, and so on. In this paper, the sheet PES hollow fiber membranes were prepared. The morphology and performance of membranes can be controlled. By studying the influence of the compositions and conditions on the morphology and performance of PES hollow fiber membrane, the relationship of morphology and performance of the membrane is acquired. The additives were used such as glycerol, BuOH and PEG. In addition, immerse phase inversion was used as membranes preparation method. The morphology of the membrane was controlled by changing kinds of additive, concentration of additive and so on. It was found that the membrane morphologies were changed by additive obviously. Porosity , pure water flux, scanning electron microscopy(SEM) were used to characterize the morphology and performance of the membranes.


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