scholarly journals Hydrophilic modification of poly(vinylidene fluoride) ultrafiltration membranes by surface UV photo-grafting with N,N′-methylene-bisacrylamide as monomer and Ce(IV) as initiator

2015 ◽  
Vol 6 (2) ◽  
pp. 280-289
Author(s):  
Baoli Shi ◽  
Zheng Li ◽  
Xing Su
Keyword(s):  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Ultrafiltration Membranes ◽  
Water Contact ◽  
Pvdf Membrane ◽  
Hydrophilic Modification ◽  
Poly Vinylidene Fluoride ◽  
Modified Membrane ◽  
Porosity Measurements ◽  
Pure Pvdf

A UV photo-grafting method was utilised to enhance the hydrophilicity and anti-fouling property of self-made poly(vinylidene fluoride) (PVDF) ultrafiltration membranes. N,N′-methylene-bisacrylamide (MBAA) was used as monomer and Ce(IV) was used as initiator to obtain balance between grafting treatment consumption and enhanced performance. MBAA could be grafted onto the surface of pure PVDF membranes through a water-phase grafting method under UV photoradiation. When the MBAA concentration was 0.07 mol/L, the Ce(IV) concentration was 0.04 mol/L, and the irradiation duration was 3 min, the membrane surface was grafted with a sufficient amount of monomer under a UV photoradiation intensity of 5.0 mW/cm2. The water contact angle on the surface of the modified membrane decreased by approximately 16°, and flux recovery increased by approximately 40% compared with the pure PVDF membrane when treating river water. For bovine serum albumin rejection and porosity measurements no significant changes were observed between pure PVDF and graft-treated membranes. The enhanced performance of the modified membrane in this work was moderate, but the UV irradiation duration (3 min) was short. The integrative effects of UV modification in this work were satisfactory when both irradiation duration and enhanced performance were considered.

scholarly journals The Modification of PVDF Membrane via Crosslinking with Chitosan and Glutaraldehyde as the Crosslinking Agent

2018 ◽  
Vol 18 (1) ◽  
pp. 1
Author(s):  
Romaya Sitha Silitonga ◽  
Nurul Widiastuti ◽  
Juhana Jaafar ◽  
Ahmad Fauzi Ismail ◽  
Muhammad Nidzhom Zainol Abidin ◽  
...  
Keyword(s):  
Contact Angle ◽  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Crosslinking Agent ◽  
Hydrophobic Properties ◽  
Pvdf Membrane ◽  
Pure Water Flux ◽  
Modified Membrane

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.

Preparation and characterization of anti-fouling PVDF membrane modified by chitin

2017 ◽  
Vol 37 (3) ◽  
pp. 313-321 ◽  
Author(s):  
Manman Xie ◽  
Xia Feng ◽  
Juncheng Hu ◽  
Zhengyi Liu ◽  
Zijian Wang ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Solvent System ◽  
Pvdf Membrane ◽  
Blend Membrane ◽  
Poly Vinylidene Fluoride ◽  
And Performance ◽  
Membrane Structure And Performance ◽  
Precipitation Phase

Abstract Poly(vinylidene fluoride) (PVDF)/chitin (CH) blend membranes were prepared via the method of immersion-precipitation phase transformation with the solvent system N,N-dimethylacetamide (DMAc)/lithium chloride (LiCl) as solvent and water as coagulant. The effect of CH on membrane structure and performance was investigated. Owing to the strong hydrophilicity, CH chains enriched on the blend membrane surface and improved the hydrophilicity of the membrane. The addition of CH also led to the formation of finger-like pores and the increase of pore size and porosity. The flux and the flux recovery ratio (FRR) of the blend membrane were higher than that of pure PVDF membrane. The fouling resistance of the blend membrane was lower than that of PVDF original membrane. In a word, the addition of CH to PVDF membrane improved the hydrophilicity and the anti-fouling ability of PVDF membrane.

Hydrophilic Modification of PVDF Membrane by Using PHEMA-PDMS-PHEMA Amphiphilic Copolymer as Addictive

2015 ◽  
Vol 799-800 ◽  
pp. 16-20
Author(s):  
Dan Li ◽  
Chun Ju He
Keyword(s):  
Vinylidene Fluoride ◽  
Pure Water ◽  
Water Flux ◽  
Amphiphilic Copolymer ◽  
Water Recovery ◽  
Hydroxyethyl Methacrylate ◽  
Water Contact ◽  
Pvdf Membrane ◽  
Hydrophilic Modification ◽  
Copolymer Poly

The hydrophilic modification of poly (vinylidene fluoride) (PVDF) membrane is achieved by using amphiphilic copolymer poly (2-hydroxyethyl methacrylate)-b-polydimethylsiloxane-b-poly (2-hydroxyethyl methacrylate) (PHEMA-b-PDMS-b-PHEMA) as addictive. The copolymer is synthesized via atom transfer radical polymerization (ATRP) and the membranes are prepared by non-solvent induced phase separation. The addition of amphiphlic copolymer has significant influence on membrane hydrophilicity and anti-fouling property. As the addictive content increasing, the water contact angle is decreased from 92° to 65°, water flux and pure water recovery rate are increased from 52.9L/m2h to 263.3 L/m2h and 71 to 95%, respectively.

Surface Modification of Poly(Vinylidene Fluoride) Microporous Membrane by Ferric Hydroxide Sol-Gel

2011 ◽  
Vol 343-344 ◽  
pp. 637-642 ◽  
Author(s):  
Ya Jie Xie ◽  
Wan Peng Hu ◽  
Zhuan Wang ◽  
Song Xu
Keyword(s):  
Surface Modification ◽  
Vinylidene Fluoride ◽  
Ferric Hydroxide ◽  
Contact Angles ◽  
Attenuated Total Reflection ◽  
Water Contact ◽  
Pvdf Membrane ◽  
Water Cleaning ◽  
Poly Vinylidene Fluoride ◽  
Adsorption Amount

Surface modification of poly(vinylidene fluoride) (PVDF) membrane was accomplished by the adsorption of ferric hydroxide sol to impove its hydrophilicity. The adsorption curves of the membranes were analyzed by weight measurements, and the typical results showed a two-platform character in low concentration. The effects of the adsorption time, the ferric hydroxide sol concentration, the test temperature, as well as the water cleaning time on the adsorption amount were observed. Attenuated total reflection-Fourier transform infrared spectroscopy (ATR/ FTIR) analysis showed that the adsorption of ferric hydroxide sol on poly(vinylidene fluoride) microporous membranes (PVDFMM) is effective. The membranes hydrophilic performance was represented by water contact angle measurements. The water contact angles changes from the virgin 128°to the lowest value 81.90° in the range of 0~0.10 mol/L ferric hydroxide aqueous solution. The results indicated that ferric hydroxide sol can be immobilized on the PVDF films by adsorption, and the membrane hydrophilic performence increases with the increase of the adsorption amount of the ferric hydroxide sol onto the PVDF membrane surface.

Enhanced antifouling ability of a poly(vinylidene fluoride) membrane functionalized with a zwitterionic serine-based layer

RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 85612-85620 ◽  
Author(s):  
Jing Zhu ◽  
Dapeng Liu ◽  
Chunju He
Keyword(s):  
Free Radical ◽  
Vinylidene Fluoride ◽  
Membrane Surface ◽  
Cross Linking ◽  
Surface Immobilization ◽  
Pvdf Membrane ◽  
Poly Vinylidene Fluoride ◽  
Antifouling Ability

Antifouling PVDF membrane was fabricated through covalently surface immobilization of zwitterionic serine-based layer via facile free radical cross-linking polymerization of serine methacrylate (SerMA) on membrane surface.

Fast and simple fabrication of SiO2/poly(vinylidene fluoride) coated cotton fabrics with asymmetric wettability via a facile spray-coating route

2018 ◽  
Vol 89 (6) ◽  
pp. 1013-1026 ◽  
Author(s):  
Rongrong Yu ◽  
Mingwei Tian ◽  
Lijun Qu ◽  
Shifeng Zhu ◽  
Jianhua Ran ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Vinylidene Fluoride ◽  
Spray Coating ◽  
Cotton Fabrics ◽  
Water Repellent ◽  
Water Contact ◽  
Repellent Property ◽  
Poly Vinylidene Fluoride

Cotton fabrics with hydrophilic-to-hydrophobic asymmetric surfaces are attractive as potential utilizable structures for functional garments. The spray-coating route could be deemed as a fast and simple way to achieve asymmetric surfaces. In this paper, SiO2 nanoparticles with size ∼ 205 nm were synthesized via the modified sol-gel method, and then modified with poly(vinylidene fluoride) (PVDF) to form a hydrophobic surface. The SiO2 nanoparticles modified with PVDF were uniformly deposited on the outer surface of cotton fabric aided with the robust air flow force from the sprayer. The morphology and chemical structures were characterized by scanning electron microscopy, mapping, atomic force microscopy, X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy. The results indicated that SiO2 nanoparticles were evenly deposited on the surface of cotton fibers and stable interfacial interaction occurred between SiO2 and PVDF molecular chains. The existence of SiO2 could increase the roughness of the fabric surface, which could enhance the water-repellent property of the coated fabrics. Furthermore, the water-repellent property and thermal insulation properties were evaluated via the water contact angle and thermal conductivity tests, respectively, and the results showed that 20 wt.% SiO2/PVDF fabric achieved a desirable level of contact angle, 136.6°, which was the largest water contact angle among all the samples, and the lowest thermal conductivity of 0.033 W/mK, resulting from the existence of SiO2 nanoparticles. Such a fast and simple spray-coating strategy could be widely introduced into asymmetric fabric modification, and such asymmetric fabrics with reasonable water-repellent and thermal insulating outer surfaces could act as candidates in the field of functional garments.

scholarly journals Fabrication of Tween-20 coated PVDF membranes for wastewater treatment: optimization of preparation parameters, removal and membrane fouling control performance

RSC Advances ◽  
2019 ◽  
Vol 9 (35) ◽  
pp. 20035-20043 ◽  
Author(s):  
Daoji Wu ◽  
Weiwei Zhou ◽  
Xiaoxiang Cheng ◽  
Congwei Luo ◽  
Peijie Li ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Vinylidene Fluoride ◽  
Tween 20 ◽  
Treatment Optimization ◽  
Sorbitan Monolaurate ◽  
Coating Agent ◽  
Hydrophilic Modification ◽  
Fouling Control ◽  
Poly Vinylidene Fluoride ◽  
Microfiltration Membranes

In the present study, polyoxyethylene (20) sorbitan monolaurate (Tween-20) was employed as a surface coating agent for hydrophilic modification of poly(vinylidene fluoride) microfiltration membranes.

scholarly journals Fabrication of a PVDF membrane with tailored morphology and properties via exploring and computing its ternary phase diagram for wastewater treatment and gas separation applications

RSC Advances ◽  
2020 ◽  
Vol 10 (66) ◽  
pp. 40373-40383
Author(s):  
S. Ashtiani ◽  
M. Khoshnamvand ◽  
P. Číhal ◽  
M. Dendisová ◽  
A. Randová ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Wastewater Treatment ◽  
Phase Separation ◽  
Ternary Phase ◽  
Vinylidene Fluoride ◽  
Ternary Phase Diagram ◽  
Simple Approach ◽  
Hydrophobic Properties ◽  
Pvdf Membrane ◽  
Poly Vinylidene Fluoride

We report a simple approach for tailoring the morphology of poly(vinylidene fluoride) (PVDF) membranes fabricated using a nonsolvent induced phase separation (NIPS) method that sustains both the hydrophilic and hydrophobic properties.

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