Effect of Additive on the Performance of PVDF Membrane via Non-Solvent Induced Phase Separation

2014 ◽  
Vol 789 ◽  
pp. 240-248 ◽  
Author(s):  
Xiao Hui Cao ◽  
Ming Qiu ◽  
Ai Wen Qin ◽  
Chun Ju He ◽  
Hai Feng Wang

Poly (vinylidene fluoride) membranes were prepared from the ternary mixture of PVDF/ 1, 2 - propylene glycol/dimethylacetamidevianon-solvent induced phase separation (NIPS). The effect of the addition of the 1, 2 - propylene glycol content, the Coagulation Bath Temperature and the concentration of PVDF on the performance and structure of the PVDF membranes was studied in the present investigation.The results showed that with increasing polymer concentration, the mechanical strength increased,and the structure of membrane changed from finger-like macro-voids structureto sponge-like structure.It was found that water flux, breaking elongation and tensile strength of the membrane increased with increasing 1, 2 - propylene glycol content, when the content reached 41wt.%, the water flux reaches a maximum.The morphology of PVDF can be improved by the addition of 1, 2 - propylene glycol, which was changed from finger-like structure to sponge-like structure. And the dense skin layer of PVDF membranes became thicker with increasing 1, 2 – propyleneglycol. The tensile strength decreasedfrom 3.3 to 2.1MPa, breaking elongation decreased from 315% to 280% andthe pure water flux increased from 91 to 909 L·m-2·h-1. as the coagulation bath temperature (CBT) decreased from 30°C to 5°C.With this condition, the sponge-like hollow fiber membrane hassuccessfully spun.

Membranes ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 87 ◽  
Author(s):  
Daria Nevstrueva ◽  
Arto Pihlajamäki ◽  
Juha Nikkola ◽  
Mika Mänttäri

Supported cellulose ultrafiltration membranes are cast from a cellulose-ionic liquid solution by the immersion precipitation technique. The effects of coagulation bath temperature and polymer concentration in the casting solution on the membrane morphology, wettability, pure water flux, molecular weight cut-off, and fouling resistance are studied. Scanning electron microscopy, contact angle measurements, atomic force microscopy, and filtration experiments are carried out in order to characterise the obtained ultrafiltration cellulose membranes. The results show the effect of coagulation bath temperature and polymer concentration on the surface morphology and properties of cellulose ultrafiltration membranes. Optimisation of the two parameters leads to the creation of dense membranes with good pure water fluxes and proven fouling resistance towards humic acid water solutions.


e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhao-Hui Jiang ◽  
Chang-Fa Xiao ◽  
Xiao-Yu Hu

AbstractHollow fiber membranes of polyamide-6(PA6) with porous structure were prepared by a thermally induced phase-separation method. N-Ethyl-o/p-toluene sulfonamide was chosen as diluent. On the basis of scanning electron microscopy (SEM) images, porosity, bubble point pore diameter and pure water flux, the influential factors including polymer concentration, coagulation bath temperature, post-stretching were investigated. The results indicate that with the increasing of PA6 concentration ‘slit-shaped’ pores in inner surfaces and cellular structure in cross-sections disappear, correspondingly, the properties of membranes such as porosity and pure water flux become poor. As the coagulation bath temperature varied from 20 °C to 50°C, the pure water flux of membranes is improved from 136 to 244 L·m-2·h-1. Post-stretching make the ‘interfacial micro-pores’ expand due to ‘stress concentration’ phenomenon, thus changing the structure and improving the properties of membranes. PA6 hollow fiber membranes with rational structure and high performance could be obtained by altering polymer concentration, coagulation bath temperature and post-stretching.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Muhammad Azeem U. R. Alvi ◽  
Muhammad Waqas Khalid ◽  
Nasir M. Ahmad ◽  
Muhammad Bilal K. Niazi ◽  
Muhammad Nabeel Anwar ◽  
...  

Microfiltration flat sheet membranes of polyether sulfone (PES) were fabricated by incorporating varying concentrations of polymer and investigated the influence of substituting solvents. The membranes were prepared via immersion precipitation method. Different solvents that included NMP (N-methyl-2-pyrrolidone), DMF (dimethylformamide), and THF (tetrahydrofuran) were used to analyse their effect on the performance and morphology of the prepared membranes. Two different coagulation bath temperatures were used to investigate the kinetics of membrane formation and subsequent effect on membrane performance. The maximum water flux of 141 ml/cm2.h was observed using 21% of PES concentration in NMP + THF cosolvent system. The highest tensile strength of 29.15 MPa was observed using membrane prepared with 21% PES concentration in NMP as solvent and coagulation bath temperature of 25°C. The highest hydraulic membrane resistance was reported for membrane prepared with 21% PES concentration in NMP as solvent. Moreover, the lowest contact angle of 67° was observed for membrane prepared with 15% of PES concentration in NMP as solvent with coagulation bath temperature of 28°C. Furthermore, the Hansen solubility parameter was used to study the effect on the thermodynamics of membrane formation and found to be in good correlation with experimental observation and approach in the present work.


2011 ◽  
Vol 418-420 ◽  
pp. 169-172
Author(s):  
Shan Zhang ◽  
Zhen Liu

The Polysulfone Flat ultrafiltration membranes were prepared with dimethylacetamide (DMAc) as solvent and polyvinypyrrolidone (PVP) as pore forming additive. Performance of PSF membrane such as pure water flux, albumin egg rejection were investigated. In addition, the same investigations were conducted with different coagulation bath temperature and evaporation time. The results show that there were a maximum of pure water flux and a minimum of the retention of Albumin when PVP content reach 14%.


2012 ◽  
Vol 18 (3) ◽  
pp. 385-398 ◽  
Author(s):  
Reza Abedini ◽  
Mahmoud Mousavi ◽  
Reza Aminzadeh

In this study, asymmetric pure CA and CA/ TiO2 composite membranes were prepared via phase inversion by dispersing TiO2 nanopaticles in the CA casting solutions induced by immersion precipitation in water coagulation bath. TiO2 nanoparticles, which were synthesized by the sonochemical method, were added into the casting solution with different concentrations. Effects of TiO2 nanoparticles concentration (0 wt. %, 5wt.%, 10wt.%, 15wt.%, 20wt.% and 25wt.%) and coagulation bath temperature (CBT= 25?C, 50?C and 75?C) on morphology, thermal stability and pure water flux (PWF) of the prepared membranes were studied and discussed. Increasing TiO2 concentration in the casting solution film along with higher CBT resulted in increasing the membrane thickness, water content (WC), membrane porosity and pure water flux (PWF), also these changes facilitate macrovoids formation. Thermal gravimetric analysis (TGA) shows that thermal stability of the composite membranes were improved by the addition of TiO2 nanopaticles. Also TGA results indicated that increasing CBT in each TiO2 concentration leads to the decreasing of decomposition temperature (Td) of hybrid membranes.


2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaoming Zhang ◽  
Qingchen Lu ◽  
Nana Li

Abstract Membrane separation technology is widely used in wastewater purification, but the issue of membrane fouling could not be ignored. Hydrophilic modification is an effective method to reduce membrane fouling. Therefore, in this work, a hydrophilic modified polyvinylidene fluoride (PVDF) ultrafiltration membrane was prepared by polymer/non-solvent co-induced phase separation, and the effect of coagulation bath temperature on the membrane structure and performance was systematically investigated based on the previous study. With the increased of the coagulation bath temperature, the phase separation process changed from delayed to instantaneous, and the membrane surface changed from porous to dense, while the macropore structures and sponge-like pores appeared on the cross-section. Meanwhile, the pure water flux decreased from 229.3 L/(m2·h) to 2.08 L/(m2·h), the protein rejection rate increased from 83.87% to 100%, and the surface water contact angle increased from 63° to 90°. Thus, excessively high coagulation bath temperature adversely affected the permeate and separation performance, as well as antifouling performance of the membrane. This study enriched the research for preparing separation membranes by polymer/non-solvent co-induced phase separation and provided a practical and theoretical reference for controlling the membrane structure and properties by changing the coagulation bath temperature.


2015 ◽  
Vol 713-715 ◽  
pp. 2723-2726
Author(s):  
Yue Rong Shi ◽  
Gui Fang Zhang ◽  
Xing Tian Liu ◽  
Xue Tao Tian ◽  
Yi Ping Zhao ◽  
...  

In this study, poly (vinylidene fluoride) (PVDF) hybrid membranes were prepared from polymeric blend of PVDF/tannic acid (TA)-Attapulgite (ATP)/PEG system via phase inversion induced by immersion precipitation in water coagulation bath. The membrane formation mechanism of PVDF/TA-ATP/PEG casting solutions in water bath thermodynamics at different temperatures and the process of membrane formation were investigated via cloud point determination and ultrasonic time-domain reflectometry (UTDR). The structures and properties of the membrane were characterized by scanning electron microscopy (SEM), and water permeation experiment, respectively. It was found that the rate of precipitation controlled by the Coagulation-Bath thermodynamics. With the coagulation temperature increasing, the gelation line was moved to non-solvent axis and the pure water flux were decreased.


Author(s):  
Rizki Firsta Wahyuliswari ◽  
Siswanto ◽  
Prihartini Widiyanti

Polysulfone is synthetic polymer widely used as basic material for dialyzer membrane and hydrophobic so it tends to cause fouling. Cellulose acetate is non-synthetic, hydrophilic polymer which has low tendency of fouling and has good thermal stability and permeability so it is considered as alternative material for hollow fiber dialyzer. A proper hollow fiber can be achieved by setting a proper temperature of coagulation bath along the spinning process. This research aims to understand the effect of coagulation bath temperature variations on the physical characteristic such as pore size, tensile strength, swelling rate and creatinine clearance of cellulose acetate – D-glucose monohydrate hollow fibers. Hollow fibers were fabricated using spinneret at temperature variations 5°C, 10°C, 15°C dan 20°C. Physical characteristics were estimated by doing morphology test using SEM, tensile test, swelling test towards Simulated Body Fluid (SBF) and filtration test towards creatinine. Result revealed that the hollow fibers from 5°C coagulation bath temperature gives the best characteristic and performance with tensile strength 27,421 N mm-2, pore size 0,0295–0,0858 nm, swelling rate 4,18%, elongation rate 4,4 %, flux rate 1,6032–1,7956 mL cm-2 min-1 and creatinine clearance rate 40,14–48,30% so it is potential to be applied as dialyzer membrane.


2013 ◽  
Vol 457-458 ◽  
pp. 309-312 ◽  
Author(s):  
Yang Bai ◽  
Zhen Liu ◽  
Dao Bao Sun

Polysulfone (PSF) hollow fiber ultrafiltration membranes were successfully prepared by dry-wet spinning technology. Dimethylacetamide (DMAC) was used as a solvent, water was used as bore liquid and coagulation bath, polyvinylpyrrolidone (PVP) was used as polymeric additive. The effects of spinning conditions on membrane structures and properties were investigated in present study. The results indicated that with the increase of PVP concentration, pure water flux increased and developed finger-like pores were formed. High coagulation bath temperature restricted pure water flux, 30°C was the best for the preparation of high-performance ultrafiltration membranes. When the air length was 11cm, the membrane comprehensive performance was the best.


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