Elaboration and characterization of multilayer polymeric membranes: effect of the chemical nature of polymers (original) (raw)
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Jurnal Kimia Valensi
Polymer Inclusion Membranes (PIMs) have been fabricated for diffusive passive sample layers. A study of various concentrations of plasticizers and characterization of PIM performance on phosphate transport has been carried out. The composition of PIM consisted of cellulose triacetate (CTA) as the base polymer, Aliquot 336-Cl as a carrier, and 2-Nitro phenyl octyl ether (2-NPOE) as a plasticizer. The plasticizer concentration varied between 0 and 10% (w/w). The performance of PIM on phosphate transport was studied with a passive sampler filled with 15 mL 0.1 M NaCl as the internal phase. The passive samplers were deployed into the bulk phase of a phosphate solution of 0.6 mg/L for 0-48 hours. The phosphate concentration in the passive sampler was determined using the visible spectrophotometry method at 691 nm (in the bulk phase) and 710 nm (in the internal phase). PIMs were characterized for stress-strain, contact angle, surface morphology, and cross-section. The sampling rate of pho...
Indonesian Journal of Chemistry
Polymer inclusion membrane (PIM) has recently evolved as an alternative separation technique to conventional solvent extraction as it eliminates the use of toxic solvents, reduces separation cost, and simplifies the separation process. PIM is the new generation of a liquid membrane made by casting solution containing liquid phases (extractant and plasticizer/modifier) and base polymers. Despite its better performance and stability in comparison to the previous types of liquid membranes, PIM's robustness for applications on an industrial scale is still considered insufficient mainly due to its limited stability in the long-term separation process. In recent years, different approaches have been devoted to improving the stability of PIM while maintaining its performance. This review aims to summarize and evaluate the current literature on the improvement of the performance of PIMs with particular focus on the use of alternative base polymers, including non-conventional linear homo...
2020
Polymer inclusion membrane (PIM) containing cellulose triacetate (CTA) as a polymer matrix and 2-nitrophenyl octyl ether (NPOE) as a plasticizer was developed. This membrane also contained di(2-ethylhexyl)phosphoric acid (D2EHPA) and tributyl phosphate (TBP) as the carriers of metal ions. The facilitated transport of lanthanum(III) from aqueous nitrate(V) solutions across PIM was studied. It was observed that metal ions were transported from the source phase into 2M H 2 SO 4 as the receiving phase. The transport through PIM with D2EHPA as the ion carrier was found as the more effective method of lanthanum(III) removal from the aqueous solution than transport through PIM with TBP as the ion carrier.
Journal of Membrane Science, 2017
Polymer inclusion membranes (PIMs) have been prepared using cellulose triacetate (CTA) as polymer and derivatives of the commercial ionic liquid (IL) Aliquat 336, trioctyl methylammonium chloride (AlqCl), as extractants. The different ILs were prepared by exchanging chloride anion from AlqCl for other more lipophilic anions, obtaining IL derivatives AlqNO 3 and AlqSCN. PIMs containing these extractants at two different concentrations (30% and 60%) were prepared and characterized using X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), contact angle and impedance spectroscopy to obtain information on the material properties of both the surface and bulk membranes. The IL counter-anion affects the membrane's electrical parameters (dielectric constant and conductivity) as well as its hydrophobic character, which also depends on the IL concentration in the PIM formulation. Passive transport across the different PIMs using HCl and NaCl aqueous solutions was also considered, and the results obtained seem to be directly related to the hydrophilic/hydrophobic character of the studied membranes.
Journal of Membrane Science, 2014
The effect of the base-polymer and carrier concentration on the physical-chemical characteristics of polymer inclusion membranes (PIMs) is investigated. Two typical polymers used to manufacture PIMs have been tested, i.e. poly(vinyl chloride) (PVC) and cellulose triacetate (CTA), and different amounts of the ionic liquid (IL) Aliquat 336, used as extractant, were the PIMs constituents. The resulting PIMs have been characterized using different techniques to provide information on both the surface and bulk material properties. XPS results do not practically show differences in the surfaces of CTA and PVC based membranes with similar Aliquat 336 content, and the total surface coverage for Aliquat 336 concentration higher than 40% (w/w) was obtained, which was also corroborated with the results of contact angle measurements. However, membrane elastic response seems to be strongly dependent on both basepolymer and Aliquat 336 concentration, which affect Young modulus and elongation at break. The IL concentration also increases dielectric constant and the conductivity of the PIMs from both polymers according to impedance spectroscopy results, providing a rather conductive character to both kind of samples for Aliquat 336 content higher than 40% (w/w) (average conductivity around 10 À 3 (Ω m) À 1). CTA and PVC-based PIMs with Aliquat 336 content around 45% have been used in order to compare the influence of the polymer on the transport of As(V).
Separations
An electrochemical characterization of a polymer inclusion membrane (PIM) fabricated with the ionic liquid (IL) Aliquat 336 (26%) and the polymer cellulose triacetate (CTA) (76%) is presented. Considering the use of PIMs in separation systems to remove pollutants from water, the characterization was performed with NaCl solutions by measuring membrane potential, electrochemical impedance spectroscopy, and salt diffusion and results were compared with those obtained from dry membranes. Results showed a significant reduction in the membrane diffusive permeability and electrical conductivity as well as the transport number of cation Na + across the PIM when compared with solution values, which could be mainly related to the dense character of the membrane. Membrane application in the separation of different sulfonamides (sulfathiazole, sulfapyridine, sulfamethazine, and sulfamethoxazole) from water, with 1 M NaCl solution as striping phase, was also considered. These results indicated that the different chemical characteristics of the compounds, as well as the compact structure of the PIM, limited the transport of the organic molecules though it.
First Report on a Solvent-Free Preparation of Polymer Inclusion Membranes with an Ionic Liquid
Molecules, 2019
A novel and environmentally-friendly procedure for the preparation of polymer inclusion membranes (PIMs) containing an ionic liquid is presented for the first time. Traditionally, PIMs are prepared by a solvent casting method with the use of harmful organic solvents. Here we report a new solvent-free procedure based on a thermal-compression technique which involve the melting of the components of the PIM and the application of a high pressure to the melted specimen to form a flat-sheet film. In our study, we have tested different polymers, such as two cellulose derivatives as well as two thermoplastic polymers, polyurethane (TPU) and poli ε-caprolactone (PCL). The ionic liquid (IL) trioctylmethylammonium chloride (Aliquat 336) has been used to produce PIMs with a fixed composition of 70% polymer–30% IL (w/w). Both TPU and PCL polymers provide successful membranes, which have been thoroughly characterized. PIMs based on the polymer PCL showed a high stability. To test whether the pro...
Journal of Membrane Science, 2009
Ultrathin separation membranes were prepared upon alternating electrostatic adsorption of polyvinylamine (PVA) and 1,4,7,10,13,16-hexacarboxymethyl 1,4,7,10,13,16-hexaazacyclo-octadecane (az6ac), or PVA and poly(N-carboxymethyl iminoethylene) (LPEI-ac) on porous polymer supports. Membrane formation was optimum at pH 6 of the dipping solutions.
Cellulose Chemistry and Technology
Polymeric membranes used for selective transport and separation of metallic ions have emerged in recent times. Their expansion depends on the method of preparation and their suitable structure and physico-chemical characteristics. In this paper, a novel category of membranes for ions separation is reported. The membranes were synthesized by the solvent evaporation method, using a mixture of polysulfone (PSL) and cellulose triacetate (CTA) or poly(methyl methacrylate) (PMMA). The synthesized membrane exhibited hydrophobicity and thermal stability at more than 120 °C, as well as a more or less porous structure. The competitive transport of Ni(II), Zn(II) and Pb(II) from aqueous solutions through the polymeric membranes was studied. Competitive transport experiments through the synthesized membranes showed that Ni(II) was selectively and efficiently transported by the three types of membranes, a transport efficiency exceeding well over 45% being achieved by using the PSL based membrane...
Polymers, 2018
Pervaporation is a membrane-separation technique which uses polymeric and/or ceramic membranes. In the case of pervaporation processes applied to dehydration, the membrane should transport water molecules preferentially. Reactive ionic liquid (RIL) (3-(1,3-diethoxy-1,3-dioxopropan-2-yl)-1-methyl-1H-imidazol-3-ium) was used to prepare novel dense cellulose acetate propionate (CAP) based membranes, applying the phase-inversion method. The designed polymer-ionic liquid system contained ionic liquid partially linked to the polymeric structure via the transesterification reaction. The various physicochemical, mechanical, equilibrium and transport properties of CAP-RIL membranes were determined and compared with the properties of CAP membranes modified with plasticizers, i.e., tributyl citrate (TBC) and acetyl tributyl citrate (ATBC). Thermogravimetric analysis (TGA) testified that CAP-RIL membranes as well as CAP membranes modified with TBC and ATBC are thermally stable up to at least 120 • C. Tensile tests of the membranes revealed improved mechanical properties reflected by reduced brittleness and increased elongation at break achieved for CAP-RIL membranes in contrast to pristine CAP membranes. RIL plasticizes the CAP matrix, and CAP-RIL membranes possess preferable mechanical properties in comparison to membranes with other plasticizers investigated. The incorporation of RIL into CAP membranes tuned the surface properties of the membranes, enhancing their hydrophilic character. Moreover, the addition of RIL into CAP resulted in an excellent improvement of the separation factor, in comparison to pristine CAP membranes, in pervaporation dehydration of propan-2-ol. The separation factor β increased from ca. 10 for pristine CAP membrane to ca. 380 for CAP-16.7-RIL membranes contacting an azeotropic composition of water-propan-2-ol mixture (i.e., 12 wt % water).