ISSN 0965-545X, Polymer Science, Series A, 2017, Vol. 59, No. 4, pp. 566–574. © Pleiades Publishing, Ltd., 2017.
POLYMER MEMBRANES
Novel Nanocomposite Membranes Prepared with PVC/ABS and Silica Nanoparticles for C2H6/CH4 Separation1 Mahmoud Salimia,*, Vahid Pirouzfarb, and Ehsan Kianfara a
Department of Chemical Engineering, Arak Branch, Islamic Azad University, Arak, Iran Young Researchers and Elite Club, Central Tehran Branch, Islamic Azad University, Tehran, Iran *e-mail:
[email protected]
b
Received August 31, 2016; Revised Manuscript Received December 23, 2016
Abstract—Composite membranes based on polyvinyl chloride and acrylonitrile butadiene styrene (ABS) copolymer have been prepared and then filled with 2–8 wt.% of silica nanoparticles. Membranes were fabricated by solution casting method using dimethylacetamide. The performance of prepared membranes were studied for methane and ethane at the feed pressure of 1.0, 1.5, 2.0, and 3.0 bar at 35°C. By increasing the percentage of ABS, permeability of methane and ethane increased. In addition, by adding the silica nanoparticles in the membrane, permeability of gas increased in all cases. The highest gas pair selectivity for C2H6/CH4 could be obtained from PVC/ BS (20 wt.%) which loaded with 8 wt.% of silica nanoparticles. The results of this study suggest that high performance gas separation nanocomposite membranes can be attained by adopting a judicious combination of blending technique for polymeric membrane, optimized loading percentage, and feed operating conditions. DOI: 10.1134/S0965545X17040071
INTRODUCTION Over the last few decades, gas separation has involved substantial kindness not only from research subjects but also from industries application by using membranes [1]. Compared with conventional gas transport techniques, such as distillation, absorption, stripping, adsorption and cryogenic methods, which are more attractive by membranes due to higher energy saving and optimizing, environmentally friendly and easy to process for the gases separation [1–4]. Inorganic membranes in comparison with polymeric membranes seems much more promising for separating ethane from methane on an industrial scale [5–8]. Inorganic membranes are fabricated from ceramic or carbon or combination of fillers and polymeric materials, which are named composite membranes or mixed matrix membranes (MMMs). The composite membranes or MMMs with dense structure are appropriate for using in very specific separation process, for example CH4 and C2H6 separation [9–11]. These membranes have been typically modified by incorporating regular fillers such as metal oxide nanoparticles [12–14], metal organic framework (MOF) [15, 16], carbon nanotubes [7, 17, 18], carbon molecular sieve [19], zeolite [20, 21], graphene [22, 23] and silica [24]. 1 The article is published in the original.
Abilities of inorganic nanoparticles such as Al2O3, SiO2, ZrO2, Fe3O4, TiO2, and silica within the polymeric membranes are known as a way to develop the gas separation performance and to improve mechanical and thermal properties of the membranes [25]. Among them, silica nanoparticles are taken more attention because of their good physical and chemical properties, as well as potential availability antifouling 1 [24]. The resultant nanocomposite membranes from combination of polymer and silica nanoparticles can be produced by the depositing and mixing the nanoparticles on the polymeric solution. So, fillerpolymer nanocomposite membranes, developed as nanofillers dispersed at a nanoscale in polymer chain network or matrix, have been studied as an effective approach to improve the both productivity (permeability) and efficiency (selectivity) problems of polymeric membranes in gas separation. Then, the final properties and gas separation performance of nanocomposite membranes can be affected by selection of a suitable polymeric precursor and filler, loading percentage of fillers in polymeric precursors. Several polymers have been used to produce composite membranes including polysulfone [26], polyethersulfone [27], polyetherimide [28], various polyimides [4, 5, 29] and polyvinyl chloride (PVC) [10, 30–32]. Polyvi-
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NOVEL NANOCOMPOSITE MEMBRANES PREPARED Table 1. Physical properties of silica nanoparticles Properties
Silica nanoparticles
Specific surface area (BET)
180 m2/g
Particles size
5–10 nm
Density
2.4 g/cm3
Color Purity (based on metal)
White > 99.9%
nyl chloride has been the precursor of choice due to its chemical and thermal stability, as well as attractive separation performance. Khosravi et al. [10] prepared membranes from PVC and investigated the permeability and gas pair selectivity values of carbon dioxide, methane, nitrogen and oxygen in the presence of SiO2 nanoparticles. They faced with a dramatic increase in permeability and solubility. In addition, they showed increasing of the permeability of carbon dioxide/nitrogen and carbon dioxide/methane with rise of the SiO2 nanoparticle’s amount. Hassanajili et al. [33] studied the influence of silica nanoparticles in polyester precursors on CO2 and CH4 transport properties. Similar to other research studies, they also found that the pure gas permeability increases along with the rising of silica loading percentage in membranes. In another study, Moghadassi et al. [34] synthesized PVC/SBR blend gas separation membrane filled with zeolite by solution-casting technique. The filler loading effects were investigated on the membrane’s gas transport properties. The experimental results showed that the gas permeability decreased and the selectivity increased by growth of zeolite loading ratio. Results showed that the N2/CH4 selectivity was improved from 1.4 to 2.3 by increasing feed pressure from 2 to 8 bar. Many researchers have verified that the appealing advantages offered by presenting improved polymer blending methodology in the topic of polymeric membranes [4, 34–37]. Precursors blending not only can deliver the opportunity for altering the physicochemical properties of the basic polymers to attain optimized synergistic properties, but also can propose new features that are not found in any one of them. Therefore, blending technology of suitably selected precursors can suggest several advantages such as integration classes of materials with different permeation characteristics and properties and offering a simple and reproducible procedure. Due to the complexities involved in the fabrication of composite membranes and the advantages of blending and dispersing techniques for nanocomposite membranes fabrication, the main objective of this POLYMER SCIENCE, SERIES A
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study was to use best combination of polymeric precursor and selecting effective nanoparticles for optimizing gas transport factors in order to find optimum feed pressure condition and loading percentage of nanoparticle for fabrication of high performance nanocomposite membranes derived from PVC/ABS and silica nanoparticles. To our best knowledge, this is the first study on the synthesis of nanocomposite membranes derived from PVC/ABS/silica nanoparticles. The nanocomposite membranes made at different loading percentages of silica particles are used to obtain an optimum preparation and operation conditions objective of permeability and gas pair selectivity values. Furthermore, the inf luence of feed pressures on the separation performance of the membranes is analyzed. The outcomes of transport and separating CH4 and C2H6 gases are evaluated for different membranes. Therefore, the attained results in this work can shed light for further developments and improvements in the membrane fabrication and application area of further exploitation of nanocomposite materials for various separation purposes. Besides, another novelty of this work is that it enjoys using blend polymeric precursors that provide the advantage of reconciliation of two high performance polymers for membrane preparation. Two various polymeric materials have different behaviors when undergoing mix procedures. The aim of this manuscript is to fabricate another kind of nanocomposite membranes with blending of two high performance polymers (PVC/ABS) as a useful technique for optimization of gas transport properties with effective performance for CH4 and C2H6 separation. EXPERIMENTAL Materials PVC was supplied by LG Chem Company Inc. (Korea). ABS was supplied by Tabriz petrochemical company (Tabriz, IRAN). Dimethylacetamide (DMA) was procured from Merck and applied as the solvent for these polymers. The silica nanoparticles were purchased from US Research Company with size about 5−10 nm; their specification is given in Table 1. Fabrication of Nanocomposite Membrane The solution casting method was used for making polymeric membranes (PVC/ABS). PVC and ABS polymer powder were dried in a vacuum oven before adding to the solvent. Polymeric precursors were fabricated as dense films by using PVC and ABS for four compositions (i.e., 10, 20, 30 and 40 wt %) according to the following technique. In the case of pure polymeric membranes, low concentrations of PVC in a solvent, causes the membrane have a uniform and seamless. For this reason, PVC concentrations of 15% in solvent were used for initial
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solution. A known weight amount of PVC powder was dissolved in hot DMA while mixing. In the next step, the chosen ABS powder was gradually added and mixing was continued for another 24 h to allow perfect homogenization of the blended polymers. The solution was passed through a 0.2 μm filter to remove undissolved polymers and possible dust or particles. After that, the solution was casted on a clean Pyrex plate. For reducing solvent evaporation’s rate, the lid should be placed on it. Then the polymeric films or casted materials were located inside an oven. After 24 h, the solvent evaporates and the membrane are prepared slowly. Then the samples were collected after cooling under the ambient temperature. For fabricating nanocomposite membrane, the solution casting method was used. The PVC/ABS (20 wt %) polymer solution was put in a vacuum oven to evaporate impurity. Then, the silica nanoparticles were added to the solution with different weight percentages and stirred at the room temperature until the homogenous solution was obtained. Then the mixture was sonicated for 20 min to disrupt aggregation of nanoparticles and to ensure and guarantee the uniform dispersion of nanoparticles in the solvent. When adding the polymer, in order to prevent the accumulation of nanoparticles and enhancement of compatibility between polymers and nanoparticles, about 10% of polymer as season, was added before adding entire polymer solution and stirred for several hours. Then the rest of the polymer was added. Garnish was done in this way and a layer of polymer is placed on the surface of silica. This is a good way to avoid empty space between polymer and nanoparticle and creating greater consistency between them. Finally, the solution was casted on a Pyrex plate by the casting knife. The additional nanocomposite membranes were prepared in oven with mentioned procedure and cooled in the ambient conditions. Gas Permeability Test and Calculation Method Permeability and ideal selectivity of the membranes were evaluated for pure gases of C2H6 and CH4. The permeability was measured from the dp/dt (rate of pressure increase) using the following relationship:
P =
( )
dp 2.73.15 × 1010 vl , 760 AT (( p0 × 76)/14.7) dt
(1)
where P is the permeability of the membrane in Barrer (1 Barrer = 1 × 10−10 cm3 (STP) · cm/cm2 · s · cmHg), A is to effective area of the membrane (cm2), T express the operating temperature (K), v refers the volume of the down-stream chamber (cm3), l stands the membrane thickness (cm), and the feed gas pressure in the
up-stream is given by P0 in psia. Also, ideal separation factor or gas pair selectivity is defined as ratio of permeability of pure C2H6 and CH4:
PC2H6 . (2) PCH4 The sorption characteristics of nanocomposite membranes were determined for C2H6 and CH4 gases using sorption cell. The testing temperature was 30°C. The solubility coefficients were then estimated using the following equation: α C2H6/CH4 =
(3) S = C, p where C is the amount of sorption (cm3 (STP) gas)/(cm3) at the corresponding pressure p (10 atm). The diffusion coefficients were calculated using D = P/S, where P and S are the permeability and solubility coefficient, respectively. RESULTS AND DISCUSSION Scanning electron microscopy (SEM, EM3200, made by KYKY, China) measurements were used to characterize and carry out surface analysis comparison of polymeric and nanocomposite membranes. The distribution of nanoparticles in the polymeric matrix were also investigated. The images from the surface of polymeric and nanocomposite membranes are shown in Fig. 1. These images indicate how nanoparticles are distributed in the nanocomposite membranes in comparison with pure polymeric membrane. The images confirm the formation of developed membranes without defecting in such membranes and they demonstrate the adaptability and homogenization of PVC/ABS polymer and silica nanoparticles. With increase of silica nanoparticle content, their distribution in membrane remains uniform. A key concern in this work was to utilize the synergistic properties of PVC and ABS materials through blending technology. The separation performance and gas permeation values prepared for the various polymeric precursors from blends of PVC and ABS are summarized in Table 2. This table confirms that pure PVC has the minimum C2H6 and CH4 permeability, certainly due to it’s high density and rigid network and polymeric structure. The gas permeability values were higher for the other blended polymeric components. From the gas transporting properties point of view, the experimental results showed that the PVC/ABS membrane with higher ABS concentration exhibited the highest selectivity for C2H6/CH4. The attained selectivities of C2H6/CH4 were nearly comparable (in the range of 2.00–2.12) and greater than pure PVC for the PVC/ABS (40 wt %) polymeric membrane films. For example, the C2H6/CH4 selectivity of the PVC/ABS (40 wt %) membrane increased by 1.5- to two-fold
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569
(b)
10 um
10 um
(c)
1 um Fig 1. SEM images of top view of (a) pure PVC/ABS, and MMMs of (b) PVC/ABS (20 wt %)-silica (2 wt %), (c) PVC/ABS (20 wt %)-silica (8 wt %).
compared to the PVC membrane and reached 2.03 and 1.19, respectively. The data from this Table also show a very negligible increase in gas permeability and gas pair selectivity of the polymeric membranes when ABS blended with PVC in higher than 20 wt %. Generally, a minor improvement was observed in the gas pair selectivity of this polymeric membrane blend; noting that there is only a little difference in the kinetic diameter of C2H6 and CH4. As is clear from the Table 3 and Fig. 2, by increasing percentages of 10 to 40% by weight of ABS polymer as the base polymer polyvinyl chloride, in all cases, permeability of methane and ethane increases and selectivity slightly increased in the majority of cases. The increased permeability is due to the fact that PVC due to the low mobility of the polymer chain segments has low permeability which by adding ABS to polyvinyl chloride, inactivity of polymer chain reduce by the acrylonitrile of copolymer, that causes an increase in permeability of gases which is higher for methane than ethane and in some cases the permeability remained constant, most likely due to the phenylene rings (styrenic block) in the copolymer chain, which reduces the chain mobility. POLYMER SCIENCE, SERIES A
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The gas transport data are consistent with the results of permeability values used to characterize membrane manufactured from PVC by Moghadassi and coworkers [34]. For example, they report that the CH4 permeability value is 0.11 Barrer through pure PVC membranes at 2 bar feed pressure. While, for pure PVC membrane, the permeability value of 0.14 Barrer is calculated in this work. This difference is normal and probably related to different crystallinity. The results of gas separation performance for nanocomposite membranes derived from PVC/ABS (20 wt %)-silica nanoparticles with different loading percentage levels of silica which are indicated in Table 3 and Fig. 3. As it is clear from the results in this Table, at all cases, methane’s and ethane’s permeability increases by increasing the percentage levels of silica nanoparticles from 2 to 8 wt.% in PVC/ABS (20 wt %) precursor (Fig. 4). This increase is because of increasing permeability of silica nanoparticles in the polymer network and lack of compatibility of nanoparticle with the polymer which is caused changes in the intensity of polymer chains and caused the interface between organic polymers and nanoparticles with large surface areas, and in the holes caused by the interface which in general, contribute to an increase in free volume and the area,
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Table 2. Permeability and ideal gas selectivity of the PVC/ABS membranes for various compositions of ABS in PVC Variable ABS concentration, wt %
Permeability, Barrer
Selectivity
Feed pressure, bar
PC2H6
PCH4
α C2H6/CH4
1
0.12
0.10
1.19
2
1.5
0.18
0.12
1.51
3
2
0.20
0.14
1.47
4
3
0.21
0.16
1.30
1
0.30
0.19
1.60
6
1.5
0.33
0.19
1.77
7
2
0.35
0.20
1.79
8
3
0.38
0.22
1.72
1
0.54
0.27
1.98
10
1.5
0.59
0.28
2.10
11
2
0.63
0.31
2.00
12
3
0.66
0.37
1.78
1
0.65
0.33
1.97
14
1.5
0.68
0.34
2.00
15
2
0.72
0.35
2.04
16
3
0.76
0.37
2.04
1
0.69
0.34
2.03
18
1.5
0.74
0.35
2.11
19
2
0.80
0.38
2.12
20
3
0.80
0.40
2.02
1
5
9
13
17
PVC
PVC/ABS, 10 wt %
PVC/ABS, 20 wt %
PVC/ABS, 30 wt %
PVC/ABS, 40 wt %
1 Barrer = 10–10 (cm3 (STP) · cm/cm2 · s · cmHg) = 7.5 × 10–14 (cm3(STP) · cm/cm2 · s · pa)
and this hole areas are suitable places to absorb and transport of gas molecules through the polymer network. Subsequent diffusion coefficient and permeability increases. These empty spaces are visible in photos, which are taken with SEM (Fig. 1). Increasing nanoparticle in polymer causes an increase in membrane’s porosity in. These pores are suitable places for interaction between gases and provide polymer network, which helps to increase the influence and gas solubility, and thereby increases permeability. This may denote the dominant contribution of molecular sieving mechanism compared to other that usually complicated in gas molecules transport in nanocomposite membranes in comparison with polymeric membrane. The increase in CH4 and C2H6 permeability is due to an increase in both diffusivity and solubility of CH4 and C2H6 in this polymeric and composite
membrane (Table 4). The CH4 diffusivity and solubility of PVC/ABS-silica (8 wt %) composite membrane increases by 50 and 30%, respectively compared to the pure PVC/ABS. The increase and decrease in CH4 and C2H6 solubility can be due to imperfect adhesion between the polymer matrix and the nanoparticles, which results in a decrease and increase of CO2/CH4 selectivity, respectively. Gas separation data from different investigators shows good agreement on the enhancement of permeability due to the presence of filler in the polymer chain network. However, the reported results on the filler and polymer precursors are different. For instance, Moghadassi and coworkers [34] fabricated PVC/SBR blend gas separation membrane filled with zeolite. Their results showed that the gas permeability decreased and the gas pair selectivity increased, by
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Table 3. The effect of the feed pressure and silica concentration on the gas transport properties Variable
Permeability, Barrer
Selectivity
Feed pressure, bar
PC2H6
PCH4
α C2H6/CH4
1 PVC/ABS (20 wt %)
1
0.54
0.27
1.98
2
1.5
0.59
0.28
2.10
3
2
0.63
0.31
2.00
4
3
0.66
0.37
1.78
5 PVC/ABS (20 wt %)-silica (2 wt %)
1
1.03
0.47
2.21
6
1.5
1.13
0.48
2.35
7
2
1.19
0.53
2.23
8
3
1.25
0.63
1.99
9 PVC/ABS (20 wt %)-silica (4 wt %)
1
1.22
0.54
2.25
10
1.5
1.32
0.55
2.40
11
2
1.40
0.59
2.39
12
3
1.63
0.72
2.25
13 PVC/ABS (20 wt %)-silica (6 wt %)
1
1.25
0.55
2.28
14
1.5
1.52
0.59
2.55
15
2
1.57
0.61
2.55
16
3
1.84
0.79
2.35
17 PVC/ABS (20 wt.%)-silica (8 wt.%)
1
1.49
0.62
2.39
18
1.5
1.74
0.63
2.79
19
2
1.88
0.66
2.87
20
3
2.08
0.74
2.82
Nanoparticle percentage, wt %
Table 4. Diffusivity D and solubility S of measured gases in composite membranes Samples
Diffusivity D
Nanoparticle percentage, DC2H6 × 10−9, cm2/s DCH4 × 10−9, cm2/s wt %
Solubility S SC2H6, cc(STP)/cc-atm
SCH4, cc(STP)/cc-atm
1
PVC/ABS (20 wt %)
5.68 ± 0.1
2.86 ± 0.1
0.12 ± 0.01
0.013 ± 0.001
2
PVC/ABS (20 wt %)-silica (2 wt.%)
7.29 ± 0.2
3.19 ± 0.1
0.17 ± 0.01
0.020 ± 0.001
3
PVC/ABS (20 wt %)-silica (4 wt.%)
9.39 ± 0.2
3.40 ± 0.1
0.17 ± 0.01
0.021 ± 0.001
4
PVC/ABS (20 wt %)-silica (6 wt.%)
10.00 ± 0.2
3.54 ± 0.1
0.18 ± 0.01
0.022 ± 0.001
5
PVC/ABS (20 wt %)-silica (8 wt%)
14.59 ± 0.2
4.28 ± 0.1
0.14 ± 0.01
0.017 ± 0.001
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Permeability of CH4, barrer 0.45 (a)
Permeability of C2H6, barrer 0.9 (b)
5 4 3
0.30
5 4 3
0.6 2
0 0.5
2
1
0.15
0.3 1
1.5
2.5
3.5 Pressure, bar
0 0.5
2.5
1.5
3.5 Pressure, bar
Selectivity (C2H6/CH4) 2.6 (c) 2.2
4
1.8
5 3 2
1.4 1.0 0.5
1 1.5
2.5 Pressure, bar
Fig 2. (Color online) Effect of feed pressure and ABS concentration on (a) CH4 and (b) C2H6 permeability, and (c) C2H6/CH4 selectivity. (1) pure PVC/ABS, (2) PVC/ABS (10 wt %), (3) PVC/ABS (20 wt %), (4) PVC/ABS (30 wt %), and (5) PVC/ABS (40 wt %).
increasing zeolite-loading ratio. In addition, it is stated that feed pressure’s increase led to an increase in permeability. Results showed that the N2/CH4 selectivity was improved from 1.4 to 2.3 by increase of feed pressure from 2 to 8 bar. As it is clear from the results from Figs. 2 and 3, by increasing the pressure of feed gas on the PVC/ABS membranes and nanocomposite membranes derived from PVC/ABS-silica nanoparticles, permeability of methane and ethane increased mostly. But selectivity is variable. The increased permeability due to increasing solubility of two gases that have good condensability and According to Fick’s law, by increasing concentration diffusion, pressure of gas in the membrane is increased and permeability became more. As the results in these tables, increasing inlet gas pressure on the nanocomposites PVC/ABS-silica nanocomposite membrane, permeability is slightly enhanced and selectivity reduced or reminded constant except in the case of lower operating pressure and higher weight percent of silica which selectivity increased (lower than 2 bar and in 8 wt.% of silica). The mechanism of membrane permeability due to decreased absorption
binomial model in increased pressure causes compression of the polymer membrane due to a decrease free volume in the polymer network and thus reducing permeability. CONCLUSIONS The organic-inorganic or nanocomposite membranes were successively prepared based on PVC/ABS and silica nanoparticles, via blending and dispersion technique. In addition, the effect of adding ABS polymer and silica nanoparticles with various percentages and feed conditions on gas separation performance of PVC polymer was investigated. These developed membranes showed higher permeability than the PVC polymeric membrane. By increasing ABS polymer content, permeability of gases increased. Also, by increasing feed pressure, in all cases, accompanied with increase in permeability. Nevertheless, increased pressure of nanocomposites with nanoparticles of silica membrane, in all cases, associated with an increase in permeability and in most cases, allied with an increase in gas pair selectivity. On the other hand, the
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Permeability of CH4, barrer 0.87 (a)
573
Permeability of C2H6, barrer
0.67
4 5 3
2.3
2
1.7
(b) 5 4 3 2
0.47
1.1 1 1
0.27 0.5
0.5 0.5
2.5 Pressure, bar
1.5
1.5
2.5
3.5 Pressure, bar
Selectivity (CO2/N2) (c) 3.5 5 2.5
4 3 2 1
1.5 0.5
1.5
2.5 Pressure, bar
Fig. 3. (Color online) Effect of feed pressure and loading percentage of silica in PVC/ABS (20 wt %)-silica membrane on (a) CH4 and (b) C2H6 permeability, and (c) C2H6/CH4 selectivity. (1) PVC/ABS (20 wt %), (2) PVC/ABS (20 wt %)-silica (2 wt %), (3) PVC/ABS (20 wt %)-silica (4 wt %), (4) PVC/ABS (20 wt %)-silica (6 wt %), and (5) PVC/ABS (20 wt %)-silica (8 wt %).
C2H6/CH4 ideal selectivity 10.00 Nano composite membranes derived from PVC/ABS (20 wt. %)Silica nano particles
r ABS Highe tage n e perc
1.00
polymeric membranes with different ABS concentration
g din
loa ica ge l i S nta er gh perce Hi
Polymeric membrane PVC/ABS (20 wt. %)
0.10 0.1
1.0
1 2 3 4 5 3 6 7 8 9
10.0 CH4 permeability, barrers
Fig. 4. (Color online) Performance of polymeric membranes with various compositions of PVC and ABS and nanocomposite membranes with respect to trade-off line for C2H6/CH4 gas pairs separation. (1) pure PVC/ABS, (2) PVC/ABS (10 wt %), (3) PVC/ABS (20 wt %), (4) PVC/ABS (30 wt %), (5) PVC/ABS (40 wt %), (6) PVC/ABS (20 wt %)-silica (2 wt %), (7) PVC/ABS (20 wt %)-silica (4 wt %), (8) PVC/ABS (20 wt %)-silica (6 wt %), and (9) PVC/ABS (20 wt %)-silica (8 wt %). POLYMER SCIENCE, SERIES A
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C2H6/CH4 selectivity obtained for the PVC/ABS (40 wt %) polymeric membrane films were nearly comparable (in the range of 2.00–2.12) and greater than pure PVC. For example, the selectivity of the PVC/ ABS (40 wt %) membrane increased by 1.5- to 2-fold compared to the PVC membrane and reached 2.03 and 1.19, respectively. The nanocomposite membrane to improve the selectivity of pair of C2H6 and CH4 gases, considering to raise the permeability of both gases, is effective in lower feed pressure. Nevertheless, the composite membrane has been few successful in improving permeability. The novel nanocomposite membranes developed in this study can be exploited as appropriate C2H6/CH4 separation membranes with effective performance for several applications. REFERENCES 1. V. Pirouzfar, High Performance Gas Separation Carbon Molecular Sieve Membranes (Lambert Publ., USA, 2016). 2. V. Pirouzfar, S. S. Hosseini, M. R. Omidkhah, and A. Z. Moghaddam, J. Ind. Eng. Chem. 20 (3), 1061 (2014). 3. V. Pirouzfar, S. S. Hosseini, M. R. Omidkhah, and A. Z. Moghaddam, Polym. Eng. Sci. 54 (1), 147(2014). 4. S. S. Hosseini, M. R. Omidkhah, A. Z. Moghaddam, and V. Pirouzfar, Sep. Pufir. Technol. 122, 278 (2014). 5. V. Pirouzfar and M. R. Omidkhah, Iran. Polym. J. 25 (3), 203 (2016). 6. S. Heydari and V. Pirouzfar, RSC Adv. 6, 14149 (2016). 7. S. F. Soleymanipour, A. H. Saeedi Dehaghani, V. Pirouzfar, and A. Alihosseini, J. Appl. Polym. Sci. 133 (34), 43839 (2016). 8. L. Cao, X. Wang, G. Wang, and J. Wang, Polym. Int. 64 (3), 383 (2015). 9. A. Kathuria, M. G. Abiad, and R. Auras, Polym. Int. 62 (8), 1144 (2013). 10. A. Khosravi, M. Sadeghi, H. Zare Banadkohi, and M. M. Talakesh, Ind. Eng. Chem. Res. 53, 2011 (2014). 11. I. Pinnau and Z. He, J. Membr. Sci. 244, 227 (2004). 12. V. R. Pereira, A. M. Isloor, U. K. Bhat, A. F. Ismail, A. Obaid, and H.-K. Fun, RSC Adv. 5, 53874 (2015). 13. F. Moghadam, M. R. Omidkhah, E. Vasheghani-Farahani, M. Z. Pedram, and F. Dorosti, Sep. Purif. Technol. 77, 128 (2011). 14. B. Yu, H. Conga, and X. Zhao, Prog. Nat. Sci. 22(6), 661 (2012).
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SPELL: 1. antifouling
POLYMER SCIENCE, SERIES A
Vol. 59
No. 4
2017
