scholarly journals Chemically and Thermally Crosslinked PVA-Based Membranes: Effect on Swelling and Transport Behavior

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1799 ◽  
Author(s):  
Rynkowska ◽  
Fatyeyeva ◽  
Marais ◽  
Kujawa ◽  
Kujawski
Keyword(s):  
Water Sorption ◽  
Polymer Membranes ◽  
Liquid Mixtures ◽  
Poly Vinyl Alcohol ◽  
Esterification Reaction ◽  
The Novel ◽  
Membrane Composition ◽  
Alcohol Dehydration ◽  
Elongation At Break ◽  
Sulfosuccinic Acid

The novel poly(vinyl alcohol) (PVA)-based membranes were prepared using the two-step crosslinking approach: the chemical crosslinking of PVA using sulfosuccinic acid (SSA) (0–50 wt.%) and the thermal treatment (120–160 °C). The membrane composition and crosslinking temperature were optimized in terms of the mechanical and transport properties. The FTIR-ATR analysis revealed that the increase of the SSA concentration and crosslinking temperature resulted in the rise of the ester bond bands intensity due to the esterification reaction between PVA and SSA. As a consequence, the PVA-based membrane with 50 wt % SSA and crosslinked at 140 °C showed the reduced Young’s modulus (from 1266.2 MPa to 1.4 MPa) and elongation at break (from 316% to 66%) in comparison with the pure PVA membrane. The studied swelling behavior of the obtained membranes revealed significantly higher water sorption than that in methanol and propal-2-ol whatever the crosslinking temperature. The performed studies provide a new way of tailoring the membrane physicochemical properties, in particular, the surface hydrophilicity. In addition, the obtained results are crucial for the design and elaboration of the polymer membranes for the pervaporative separation of the liquid-liquid mixtures, in particular, for the alcohol dehydration.

scholarly journals Preparation and Characterizations of Zeolite – Filled Natural Rubber/Poly(vinyl alcohol) Semi–IPN Membranes

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
J. Patthana ◽  
C. Poonsawat ◽  
S. Amnuaypanich
Keyword(s):  
Natural Rubber ◽  
Vinyl Alcohol ◽  
Polymer Network ◽  
Water Concentration ◽  
Liquid Mixtures ◽  
Sem Analysis ◽  
Interpenetrating Polymer Network ◽  
Poly Vinyl Alcohol ◽  
Zeolite Content ◽  
Sulfosuccinic Acid

Semi–interpenetrating polymer network (semi–IPN) of natural rubber (NR) and crosslinked poly(vinyl alcohol) (PVA) was composited with zeolite 4A to form a mixed matrix (MM) membrane. PVA was crosslinked with sulfosuccinic acid (SSA) in the immediate presence of NR and zeolite. FT–IR spectroscopy confirmed the crosslinking of PVA in the MM membrane. Swelling measurements were carried out in both water and absolute ethanol. The degrees of swelling in both water and ethanol increased with increasing PVA content in the membranes, however they were found to decline upon increasing zeolite content more than 10 %w/w. The mechanical properties of the MM membranes were investigated by tensile testing. It was observed that the modulus increased with increasing zeolite content in membranes but the elongation at break was found to decrease. The thermal degradation of the MM membranes was studies using thermal gravimetry (TG). The MM membranes showed higher thermal stability compared with NR/PVA membrane due to the incorporation of zeolite. The dispersion of zeolite particles in the MM membrane was observed by scanning electron microscopy (SEM) analysis which showed a well dispersing of zeolite particles in the semi–IPN matrix. The sorption selectivities of MM membranes were enhanced with zeolite content especially, at low water concentration of ethanol–water mixtures. However the sorption selectivities of MM membranes decreased when water content in the liquid mixtures increased.

Cellulose Based Electrospun Nanofilters: Perspectives On Tannery Effluent Waste Water Treatment

2021 ◽  
Author(s):  
Senthil Rethinam ◽  
Sardar Batıkan Kavukcu ◽  
Thiagarajan Hemalatha ◽  
A.Wilson Aruni ◽  
Aylin Sendemir
Keyword(s):  
Metal Ions ◽  
Waste Water Treatment ◽  
Toxic Metal ◽  
Poly Vinyl Alcohol ◽  
Tannery Effluent ◽  
Tea Leaves ◽  
Leather Industry ◽  
Elongation At Break ◽  
Hazardous Metal ◽  
Effluent Waste

Abstract Development of nanofilters with the capability to remove toxic metal ions from effluent wastewater will be of immense help to the leather industry. In this study, fibrous nanofilter (FNF) was prepared using micro cellulosic fiber (MCF) and tea leaves microparticles (TLM) blended in poly (vinyl) alcohol (PVA). FNF was analysed for its efficacy to remove hazardous metals from tannery effluent wastewater. The FNF had promising traits of tensile strength (19.24+0.05 Mpa), elongation at break (22.31+0.12 %), flexibility (10.88+0.05 %), water absorption (37.86+0.14 %) and desorption (32.54+0.33 %). The metal adsorption studies clearly reflected the removal of toxic Cr (VI) ions from the effluent water by FNF. The study establishes an economically feasible and highly efficient way to remove hazardous metal ions from effluent wastewater.

scholarly journals Development of poly(vinyl alcohol)-based membranes by the response surface methodology for environmental applications

2020 ◽  
Vol 24 ◽  
pp. e5
Author(s):  
Juliana Zanol Merck ◽  
Camila Suliani Raota ◽  
Jocelei Duarte ◽  
Camila Baldasso ◽  
Janaina Da Silva Crespo ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Citric Acid ◽  
Response Surface ◽  
Acid Concentration ◽  
Vinyl Alcohol ◽  
Membrane Preparation ◽  
Poly Vinyl Alcohol ◽  
Esterification Reaction ◽  
Citric Acid Concentration ◽  
Ft Ir

The pollution of hydric sources by pharmaceuticals is an issue in many countries, particularly in Brazil. The presence of these substances causes deleterious effects on the environment and human health. One of the main sources of this contamination is domestic sewage, due to the expressive amount of medicines released in their unaltered form. Unfortunately, traditional wastewater treatment is not effective for the removal of pharmaceuticals and, for this reason, membrane technology is an attractive alternative to overcome this issue. In this regard, hydrophilic polymers, such as poly(vinyl alcohol) (PVA), are the most suitable. However, their high affinity with water causes intense swelling, leading to severe modifications in the membrane properties. In view of all these facts, the present work evaluated the swelling of PVA-based membranes, with the aim of finding the membrane preparation method that has the lowest swelling, thereby providing the most suitable characteristics for pharmaceutical removal from wastewater. The membranes were prepared by the casting of a polymeric solution, with PVA as a basis polymer, citric acid as a crosslink agent and glycerol and silver nanoparticles as performance additives. The process optimization was performed using a design of experiments with posterior analysis by the response surface methodology (RSM). The RSM assessed the effect on the membrane swelling of the factors, including citric acid concentration and the time and temperature of crosslinking. The membrane characterization was performed by Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy coupled with a field emission gun (SEM-FEG) and water contact angle (WCA) measurements. Overall, the condition that showed the lowest swelling was obtained with 10% of citric acid and crosslinking for 4 h at 130 °C. Under these conditions, the membrane had a mass swelling of 42% and a dimensional swelling of 24%. Additionally, our statistical analysis revealed that the factors with the dominant effects were the citric acid concentration and the temperature of crosslinking. The FT-IR analysis suggested that the crosslinking occurred by an esterification reaction, as showed by the stretching frequencies of C=O at 1710 cm-1 and ester C-O at 1230 cm-1. Moreover, the SEM-FEG images revealed a smooth and flat surface and a dense cross section with a thickness of ~113 μm. Concerning the WCA, the angle was at ~80°, which is characteristic of hydrophilic materials. Finally, the data suggested that it is possible to optimize the membrane preparation process with adequate properties so that it can be subsequently applied to the removal of pharmaceuticals from hospital wastewater.

scholarly journals The Effect of Adhesive Additives on Silica Gel Water Sorption Properties

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 327
Author(s):  
Karol Sztekler ◽  
Wojciech Kalawa ◽  
Agata Mlonka-Medrala ◽  
Wojciech Nowak ◽  
Łukasz Mika ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Silica Gel ◽  
Water Sorption ◽  
High Reliability ◽  
Electricity Consumption ◽  
Hydroxyethyl Cellulose ◽  
Poly Vinyl Alcohol ◽  
Dynamic Adsorption ◽  
Metal Plates ◽  
The Impact

Adsorption chillers are characterized by low electricity consumption, lack of moving parts, and high reliability. The disadvantage of these chillers is their large weight due to low adsorbent sorption capacity. Therefore, the attention is turned to finding a sorbent with a high water sorption capacity and enhanced thermal conductivity to increase chiller efficiency. The article discusses the impact of selected adhesives used for the production of an adsorption bed in order to improve heat exchange on its surface. Experiments with silica gel with three commercial types of glue on metal plates representing heat exchanger were performed. The structure of samples was observed under a microscope to determine the coverage of adsorbent by glue. To determine the kinetics of the free adsorption, the amounts of moisture adsorbed and the desorption dynamics the prepared samples of coated bed on metal plates were moisturized and dried in a moisture analyzer. Samples made of silica gel mixed with the adhesive 2-hydroxyethyl cellulose, show high adsorption capacity, low dynamic adsorption, and medium dynamic desorption. Samples containing adhesive poly(vinyl alcohol) adsorb less moisture, but free adsorption and desorption were more dynamic. Samples containing the adhesive hydroxyethyl cellulose show lower moisture capacity, relatively dynamic adsorption, and lower dynamic desorption.

Effects of Polyvinylamine and Polyvinyl Alcohol on DOP Migration of PVC Film

2013 ◽  
Vol 411-414 ◽  
pp. 2993-2996
Author(s):  
Yu Pu Deng ◽  
Lin Xue Du ◽  
Xi Hong Li ◽  
Xia Liu ◽  
Hai Jiao Liu
Keyword(s):  
Tensile Strength ◽  
Thermogravimetric Analysis ◽  
Polyvinyl Alcohol ◽  
Tensile Properties ◽  
Migration Rate ◽  
Control Sample ◽  
Mixed Solution ◽  
The Novel ◽  
Elongation At Break ◽  
Pvc Film

The novel packaging was synthesised by coating polyvinyl chloride (PVC) film with Polyvinylamine/Polyvinyl alcohol (PVAm/PVA) mixture which can effectively inhibit the migration of DOP in this paper. The effect of PVAm/PVA mixture on inhibiting DOP migration was detected via extraction tests. The results showed that the novel packaging significantly reduced the migration rate of DOP compared with the control (PVC film). After 24h extracted by hexane 40% PVAm in mixture being coated on PVC had the lowest migration rate (6.20%) among the samples, while 7.60% is the migration rate of control sample. Tensile properties analysis indicated the elongation at break and tensile strength of samples coating PVAm/PVA higher than control sample. The thermogravimetric analysis demonstrated that the PVAm/PVA mixed solution can deduce thermogravimetric rate. Therefore, coating PVC with PVAm/PVA mixture is an effective approach to suppress the migration of DOP.

Development of crosslinked plasma-graft filling polymer membranes for the reverse osmosis of organic liquid mixtures

2005 ◽  
Vol 265 (1-2) ◽  
pp. 101-107 ◽  
Author(s):  
T KAI ◽  
H GOTO ◽  
Y SHIMIZU ◽  
T YAMAGUCHI ◽  
S NAKAO ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Organic Liquid ◽  
Polymer Membranes ◽  
Liquid Mixtures
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