scholarly journals Separation of Benzene/Cyclohexane Mixtures by Pervaporation Using Poly (Ethylene-Co-Vinylalcohol) and Carbon Nanotube-Filled Poly (Vinyl Alcohol-Co-Ethylene) Membranes

Separations ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 68
Author(s):  
Hala Zahlan ◽  
Waseem Sharaf Saeed ◽  
Saad Alqahtani ◽  
Taieb Aouak
Keyword(s):  
Carbon Nanotube ◽  
Separation Factor ◽  
Vinyl Alcohol ◽  
Azeotropic Mixture ◽  
Poly Vinyl Alcohol ◽  
Permeate Flux ◽  
Scanning Calorimetry ◽  
Absorption Area ◽  
Poly Ethylene ◽  
Pervaporation Separation

Poly(ethylene-co-vinylalcohol) (E-VOH) and carbon nanotube-filled poly (vinyl alcohol-co-ethylene) (E-VOH/CNT) were used as membranes to separate benzene/cyclohexane mixtures by pervaporation technique. To reach this goal, E-VOH and E-VOH/CNT membranes were prepared by solvent casting method and characterized by differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The swelling tests were used to study the mass transfer of the benzene/cyclohexane mixture and their pure components. The separation by pervaporation process was carried out at 25 °C in which the effect of CNTs incorporated into E-VOH matrix and the initial concentration of benzene in the feed on the permeate flux, j, and separation factor, β, performance was investigated. The results obtained were very promising, in which the integration of CNTs through E-VOH chains increased the absorption area and raised the flux to 740 g/m2∙h. The separation factor increased to 9.03 and the pervaporation separation reached an index of 5942.2 g/m2∙h for the azeotropic mixture during 3 h of the separation process. In contrast, for the unfilled E-VOH membrane, it was found that these parameters were a rise of 280 g∙m−2∙h−1, separation factor of 12.90 and pervaporation separation index of 3332.0 g/m2∙h, under the same conditions. Likewise, the calculation of the performance of the E-VOH/CNT membrane with regard to that of the unfilled membrane indicated 2.64 for the total flux and 0.70 for the separation factor. It was also revealed that the best compromise of the filled membrane in terms of total cumulative flux and separation factor is obtained for the feed containing the azeotropic mixture.

scholarly journals Single and binary protein electroultrafiltration using poly(vinyl-alcohol)-carbon nanotube (PVA-CNT) composite membranes

2020 ◽  
Author(s):  
Raymond Yeung ◽  
Xiaobo Zhu ◽  
Terence Gee ◽  
Ben Gheen ◽  
David Jassby ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Membrane Fouling ◽  
Vinyl Alcohol ◽  
Protein Separation ◽  
Composite Membranes ◽  
Poly Vinyl Alcohol ◽  
Permeate Flux ◽  
Nanotube Membranes ◽  
Egg White Lysozyme ◽  
Electrically Conductive Composite

AbstractElectrically conductive composite ultrafiltration membranes composed of carbon nanotubes have exhibited efficient fouling inhibition in wastewater treatment applications. In the current study, poly(vinyl-alcohol)-carbon nanotube membranes were applied to fed batch crossflow electroultrafiltration of dilute (0.1 g/L of each species) single and binary protein solutions of α-lactalbumin and hen egg-white lysozyme at pH 7.4, 4 mM ionic strength, and 1 psi. Electroultrafiltration using the poly(vinyl-alcohol)-carbon nanotube composite membranes yielded temporary enhancements in sieving for single protein filtration and in selectivity for binary protein separation compared to ultrafiltration using the unmodified PS-35 membranes. Assessment of membrane fouling based on permeate flux, zeta potential measurements, and scanning electron microscopy visualization of the conditioned membranes indicated significant resulting protein adsorption and aggregation which limited the duration of improvement during electroultrafiltration with an applied cathodic potential of −4.6 V (vs. Ag/AgCl). These results imply that appropriate optimization of electroultrafiltration using carbon nanotube-deposited polymeric membranes may provide substantial short-term improvements in binary protein separations.

Poly(Vinyl Alcohol) Fiber Reinforced High Density Poly(Ethylene) Composites: Melting and Crystallization Behavior

2018 ◽  
Vol 773 ◽  
pp. 100-105
Author(s):  
Umi Rofiqah ◽  
Achmad Chafidz ◽  
Lilis Kistriyani ◽  
Mujtahid Kaavessina ◽  
Muhammad Rizal ◽  
...  
Keyword(s):  
Vinyl Alcohol ◽  
Crystallization Behavior ◽  
Crystallinity Index ◽  
Fiber Composites ◽  
High Density ◽  
Peak Temperature ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
Poly Ethylene ◽  
Pva Fiber

In the present study, high density poly(ethylene) (HDPE)/poly(vinyl alcohol) (PVA) fiber composites were prepared via melt blending technique using a co-rotating twin screw extruder (TSE). The effect of four different PVA fiber concentrations (i.e. 0, 5, 10, 20 wt%) on the melt and crystallization behavior of the HDPE/PVA fiber composites were investigated. The surface morphology of the composites was analyzed by a scanning electron microscopy (SEM). Whereas, the melt and crystallization behavior of the composites were analyzed by a differential scanning calorimetry (DSC). The SEM analysis on the cryo-fractured surface of the HDPE/PVA fiber composites exhibited that the PVA fibers were well blended/distributed in the HDPE matrix. Additionally, the DSC test results showed that the addition of PVA fiber in the HDPE matrix did not significantly change the melting peak temperature (Tm) of the composites. Furthermore, a slight decrease of the crystallization peak temperature (Tc) can be observed when the PVA fiber was incorporated in the HDPE matrix, which indicated a weak nucleation ability of the PVA fibers in the HDPE crystallization process. The same trend was also observed for the crystallinity index (Xc). The crystallinity index of the composites decreased with increasing PVA fiber loadings.

scholarly journals Separation of Aqueous Isopropanol Through Chitosan/Poly (Vinyl Alcohol) Blended Membranes by Pervaporation

1970 ◽  
Vol 2 (2) ◽  
Author(s):  
S. H. Tan, A. L. Ahmad ◽  
M. G. Mohd. Nawawi and H. Hassan
Keyword(s):  
Separation Factor ◽  
Vinyl Alcohol ◽  
Operating Conditions ◽  
Poly Vinyl Alcohol ◽  
Feed Concentration ◽  
Casting Method ◽  
Blend Ratio ◽  
Solution Casting Method ◽  
Pervaporation Separation ◽  
Aqueous Isopropanol

Blend membranes consisting of chitosan/poly (vinyl alcohol) (CS/PVA) were prepared from a solution casting method and characterized via the pervaporation separation of isopropanol-water mixtures.  The solution of pure chitosan was blended with poly(vinyl alcohol) at different compositions. The miscibility of the blended polymers was determined.  Criteria for miscibility was based on the clarity of the blend and the transparency of the membrane obtained.  The effects of feed concentration and chitosan content in membrane on the permeation flux and separation factor were also investigated. For the dehydration of 90 wt.% of isopropanol-water mixtures the performance of the blend ratio of 30:70 (CS:PVA) exhibited the highest separation factor. It was shown that under the same operating conditions, the pervaporation separation index (PSI) for homogeneous membranes were higher than that of blended membranes for the entire feed concentrations.Key Words: Blend, Chitosan, Poly (vinyl alcohol), Miscibility, Pervaporation.

Effect of Cobalt Stearate and Vegetable Oil on Uv and Biodegradation of Linear Low-Density Poly(Ethylene)-Poly(Vinyl Alcohol) Blends

2011 ◽  
Vol 2 (4) ◽  
pp. 131-148 ◽  
Author(s):  
Francis Vidya ◽  
Subin S. Raghul ◽  
Sarita G Bhat ◽  
Eby Thomas Thachil
Keyword(s):  
Vegetable Oil ◽  
Vinyl Alcohol ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Low Density ◽  
Compression Moulding ◽  
Melt Mixing ◽  
Degradation Behaviour ◽  
Moulding Process ◽  
Poly Ethylene

The main objective of this study was to enhance the rate of UV and biodegradation of polyethylene by incorporating biodegradable materials and prooxidants. Prooxidants such as transition metal complexes are capable of initiating photooxidation and polymer chain cleavage, rendering the product more susceptible to biodegradation. In this work, the effect of (1) a metallic photoinitiator, cobalt stearate, and (2) different combinations of cobalt stearate and vegetable oil on the photooxidative degradation of linear low-density poly(ethylene)-poly(vinyl alcohol) (LLDPE/PVA) blend films has been investigated. For this, film-grade LLDPE was blended with different proportions of PVA. PVA is widely used in the industrial field, and recently it has attracted increasing attention as a water-soluble biodegradable polymer. Cobalt stearate and vegetable oil were added to the blends as prooxidants. The blends were prepared by melt mixing in a Thermo HAAKE Polylab system. Thin films containing these additives were prepared by a subsequent compression moulding process. The effect of UV exposure on LLDPE/PVA films in the presence as well as absence of these additives was investigated. Tensile properties, FTIR spectra, and scanning electron microscopy (SEM) were employed to investigate the degradation behaviour. It was found

Miscible blends of poly(ethylene oxide) with brush copolymers of poly(vinyl alcohol)-graft -poly(l -lactide)

2016 ◽  
Vol 54 (13) ◽  
pp. 1217-1226 ◽  
Author(s):  
Ainhoa Lejardi ◽  
Jose-Ramon Sarasua ◽  
Agustin Etxeberria ◽  
Emilio Meaurio
Keyword(s):  
Ethylene Oxide ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
Miscible Blends ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene
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