scholarly journals Improved salt rejection, hydrophilicity and mechanical properties of novel thermoplastic polymer/chitosan nanofibre membranes

2020 ◽  
Vol 15 ◽  
pp. 155892502092317
Author(s):  
Fahad S Al-Mubaddel ◽  
Hamad S AlRomaih ◽  
Mohammad Rezaul Karim ◽  
Monis Luqman ◽  
Maher M Al-Rashed ◽  
...  

The present study reports on the preparation of novel nanofibre membranes from the thermoplastic polymer polyvinylidene fluoride coated with chitosan to enhance membrane properties such as hydrophilicity, mechanical properties, water flux and salt rejection. Initially, a supporting layer was produced from polyvinylidene fluoride using phase inversion methods, followed by being coated with chitosan using either electrospinning or immersion methods. Two types of fabricated membranes with different coating methods were characterized and tested for physical and chemical performance using field-emission scanning electron microscopy, tensile tests, permeation tests (water flux and salt rejection) and contact angle measurements. It was found that the support membrane (polyvinylidene fluoride) produced by the phase inversion method that was coated with chitosan using electrospinning showed better performance, with a salt rejection up to 70% for MgSO4, a decreased the contact angle (52°) and improved the elongation at the breaking point (~82%).

2013 ◽  
Vol 746 ◽  
pp. 390-393
Author(s):  
Qiong Zhi Gao ◽  
Hong Qiang Li ◽  
Xing Rong Zeng

In this study, polyvinylidene fluoride (PVDF) composite ultrafiltration membranes were prepared by a phase inversion method, N,N-dimethylacetamide (DMAc) was used as solvent and polyvinylpyrrolidone (PVP) was used as dispersant, nanoTiO2 and AgNO3 were used as addictive materials. With different doping content of nanoTiO2 and silver ions, those hybrid films have different functions and structure. The basic performance and photocatalytic properties of those ultrafiltration membranes were studied in detail. The experiment results show that adding nanosized TiO2 particles will make the porosity of PVDF membrane increase, adding silver ion with low content can not improve water flux and porosity of membranes, however, nanoTiO2 and silver ions doping together can effectively improve the photocatalytic degradation rate.


2019 ◽  
Vol 69 (2) ◽  
pp. 122-133 ◽  
Author(s):  
Juan Xiong ◽  
Yexia Gong ◽  
Cong Ma ◽  
Xingtao Zuo ◽  
Jiajie He

Abstract The hydrophilic and antimicrobial polyvinylidene fluoride (PVDF) membrane was fabricated by phase inversion method. The prepared membranes with various concentrations of ZnO nanoparticles (NPs) were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and membrane properties were investigated in terms of hydrophilicity, water flux, BSA solution filtration experiments, etc. Antibacterial testing was also performed to examine the practicability of the PVDF-ZnO membranes in overcoming biofouling. The results of FTIR and XRD confirmed the presence of ZnO NPs in the polymer matrix. The membrane performance demonstrated the significance of hydrophilic nanoparticles towards the enhancement of membrane properties. The optimum amount of ZnO NPs was 1.5 wt% with a lower contact angle as well as highest flux and lowest filtration resistance. The presence of ZnO NPs in the membrane matrix exhibited a strong antibacterial activity increased with the increasing ZnO NPs' content. Incorporation of ZnO NPs into PVDF membranes may have great potential in developing high-performance antifouling membranes for separation process.


2015 ◽  
Vol 35 (4) ◽  
pp. 377-390 ◽  
Author(s):  
Andrzej Ambroziak

Abstract This article describes the laboratory tests necessary to identify the mechanical properties of the polyvinylidene fluoride (PVDF)-coated fabrics named Precontraint 1202S and Precontraint 1302S. First, a short survey of the literature concerning the description of coated woven fabrics is presented. Second, the material parameters for PVDF-coated fabrics are specified on the basis of biaxial tensile tests. A comparison of the 1:1 biaxial and the uniaxial tensile tests results is also given. Additionally, biaxial cyclic tests were performed to observe the change of immediate mechanical properties under cyclic load. The article is aimed as an introduction to a comprehensive investigation of the mechanical properties of coated fabrics.


Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 106 ◽  
Author(s):  
Yehia M. Manawi ◽  
Kui Wang ◽  
Viktor Kochkodan ◽  
Daniel J. Johnson ◽  
Muataz A. Atieh ◽  
...  

In this work, novel polysulphone (PS) porous membranes for water desalination, incorporated with commercial and produced carbon nanotubes (CNT), were fabricated and analyzed. It was demonstrated that changing the main characteristics of CNT (e.g., loading in the dope solutions, aspect ratio, and functionality) significantly affected the membrane properties and performance including porosity, water flux, and mechanical and surface properties. The water flux of the fabricated membranes increased considerably (up to 20 times) along with the increase in CNT loading. Conversely, yield stress and Young’s modulus of the membranes dropped with the increase in the CNT loading mainly due to porosity increase. It was shown that the elongation at fracture for PS/0.25 wt. % CNT membrane was much higher than for pristine PS membrane due to enhanced compatibility of commercial CNTs with PS matrix. More pronounced effect on membrane’s mechanical properties was observed due to compatibility of CNTs with PS matrix when compared to other factors (i.e., changes in the CNT aspect ratio). The water contact angle for PS membranes incorporated with commercial CNT sharply decreased from 73° to 53° (membrane hydrophilization) for membranes with 0.1 and 1.0 wt. % of CNTs, while for the same loading of produced CNTs the water contact angles for the membrane samples increased from 66° to 72°. The obtained results show that complex interplay of various factors such as: loading of CNT in the dope solutions, aspect ratio, and functionality of CNT. These features can be used to engineer membranes with desired properties and performance.


2014 ◽  
Vol 70 (2) ◽  
Author(s):  
Sutthisa Konruang ◽  
Thawat Chittrakarn ◽  
Suksawat Sirijarukul

The effects of ultraviolet (UV) irradiation for surface modification of hydrophobic asymmetric polysulfone membranes have been investigated. The asymmetric polysulfone (PSF) membranes were prepared by phase inversion method using 19%-25% of PSF in two solvents, viz. dimethylacetamide (DMF) and Acetone (Ac) collectively. The surface of asymmetric polysulfone membranes were modified by UV ray with 254 and 312 nm wavelength. Chemical and physical properties of the untreated and the treated membranes were characterized. Scanning electron microscope (SEM) was used to determine asymmetric structure of polysulfone membranes. Contact angle device was used to analyzed the effected of UV ray treatment on hydrophilicity of membranes surface. Polar functional groups introduced by UV irradiation were examined using FTIR. The water flux was measured under a pressure of 500 kPa to 2,500 kPa with a feed temperature of 25°C. It was shown that asymmetric polysulfone membranes were produced and the UV ray treatment significantly alters the hydrophilicity of membranes surface indicated by the reduction of water contact angle with increasing treatment time. The FTIR analysis showed the formations of polar functional groups such as hydroxyl and carbonyl groups. Consequently, the surface of asymmetric polysulfone membranes was changed from hydrophobic to hydrophilic by UV irradiation leading to the enhancement of the water flux.


2018 ◽  
Vol 80 (3-2) ◽  
Author(s):  
Ngan T. B. Dang ◽  
Liza B. Patacsil ◽  
Aileen H. Orbecido ◽  
Ramon Christian P. Eusebio ◽  
Arnel B. Beltran

Water resources are very important to sustain life. However, these resources have been subjected to stress due to population growth, economic and industrial growth, pollution and climate change. With these, the recovery of water from sources such as wastewater, dirty water, floodwater and seawater is a sustainable alternative. The potential of recovering water from these sources could be done by utilizing forward osmosis, a membrane process that exploits the natural osmotic pressure gradient between solutions which requires low energy operation. This study evaluated the potential of forward osmosis (FO) composite membranes fabricated from bacterial cellulose (BC) and modified with sodium alginate. The membranes were evaluated for water flux and salt rejection. The effect of alginate concentrations and impregnation temperatures were evaluated using 0.6 M sodium chloride solution as feed and 2 M glucose solution as the draw solution. The membranes were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Contact Angle Meter (CAM). The use of sodium alginate in BC membrane showed a thicker membrane (38.3 μm to 67.6 μm), denser structure (shown in the SEM images), and more hydrophilic (contact angle ranges from 28.39° to 32.97°) compared to the pristine BC membrane (thickness = 12.8 μm and contact angle = 66.13°). Furthermore, the alginate modification lowered the water flux of the BC membrane from 9.283 L/m2-h (LMH) to value ranging from 2.314 to 4.797 LMH but the improvement in salt rejection was prominent (up to 98.57%).


2018 ◽  
Vol 18 (2) ◽  
pp. 257 ◽  
Author(s):  
Nita Kusumawati ◽  
Pirim Setiarso ◽  
Maria Monica Sianita ◽  
Supari Muslim

Asymmetric polysulfone (PSf) membrane is prepared using phase inversion method and blending with polyvinylidene fluoride (PVDF) on the gauze solid support. Casting solution composition optimization has been done to get PSf/PVDF membrane with best characteristics and permeability. The result shows that blending on PSf with PVDF polymer using phase inversion method has been very helpful in creating an asymmetric porous membrane. Increased level of PVDF in casting solution has increased the formation of asymmetry structure and corresponding flux membrane. The result from thermal test using Differential Scanning Calorimetry (DSC)-Thermal Gravimetric Analysis (TGA) shows the resistance of the membrane to temperature 460 °C. Membrane resistance against acid looks from undetectable changes on infrared spectra after immersion process in H2SO4 6–98 v/v%. While membrane color changes from white to brownish and black is detected after the immersion process in sodium hydroxide (NaOH) 0.15–80 w/v%.


2018 ◽  
Vol 197 ◽  
pp. 09007
Author(s):  
Syawaliah Syawaliah ◽  
Nasrul Arahman ◽  
Medyan Riza ◽  
Sri Mulyati

The Polyvinylidene Fluoride (PVDF) membrane has been prepared by phase inversion method using N,N-dimethylacetamide (DMAc) as solvent and Poly Ethylene Glycol (PEG) as additive. The fabricated membrane was modified by Polydopamine (PDA) coating in concentration of 0.5 mg/ml and immersion times of 2 hours, 6 hours, and 24 hours. The characteristics and performance of the PVDF membranes before and after the modification are studied in this paper. The result of the water flux experiment showed that the PDA-coated PVDF membranes showcased a higher flux than that of pure PVDF membrane. Scanning Electron Microscopy (SEM) analysis confirmed that the membrane had an asymmetric structure consisting of two layers. There was no significant influence on the addition of PDA to the morphology of the pore matrix because the modification was done by surface coating. Fourier Transform Infrared Spectroscopy (FTIR) analysis showed that PDA was successfully introduced on the surface of PVDF membrane with the appearance of O-H from cathecol and N-H peaks at wavenumber range of 3300-3600 cm-1. Modification with PDA increased the mechanical strength of the membrane which affirmed by the results of the tensile and elongation at break evaluation.


2018 ◽  
Vol 19 (4) ◽  
pp. 1279-1285
Author(s):  
Q. Y. Zhang ◽  
Q. An ◽  
Y. G. Guo ◽  
J. Zhang ◽  
K. Y. Zhao

Abstract To enhance the anti-fouling and separating properties of polyvinylidene fluoride (PVDF) membranes, an amphiphilic copolymer of methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid, poly(MMA-co-AMPS), was designed and synthesized. Through a phase-inversion process, the poly(MMA-co-AMPS) were fully dispersed in the PVDF membrane. The properties of membrane including the surface and cross-section morphology, surface wettability and fouling resistance under different pH solutions were investigated. Compared to the unmodified PVDF membranes, the contact angles of modified PVDF membranes decreased from 80.6° to 71.6°, and the pure water flux increased from 54 to 71 L·m−2·h−1. In addition, the hybrid PVDF membrane containing 0.5 wt% copolymers demonstrated an larger permeability, better fouling resistance and higher recovery ratio via pure water backlashing, when it was compared with the other blend membranes, and the virgin one in the cyclic test of anti-fouling. The modified membranes with the copolymers possessed an outstanding performance and may be used for further water treatment applications.


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