Separation Behavior of Composite Polyamide Membranes from Mixed Amines: Effects of Interfacial Reaction Condition and Chemical Post-Treatment
TL;DR: In this paper, composite polyamide membranes are prepared using in-situ interfacial polymerization using mixed amine system comprising 1,4-phenylene diamine and pipperazine.
Abstract: Composite polyamide membranes are prepared using in-situ interfacial polymerization using mixed amine system comprising 1,4-phenylene diamine and pipperazine. Separation performance of the membranes are studied as a function of the concentration of amine and acid chloride, the concentration ratio of the amines, nature of the acid chloride, and the presence of surfactant and acid acceptor in the aqueous reagent. The effect of esterification and hydrazide reactions involving residual carboxylic acid groups in the polymeric membranes on the co-polymeric composite membrane performance is also studied. The membrane performance can be tailored easily by conversion of the residual reactive functional groups in post-treatment.
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1,167 citations
TL;DR: An overview of the chemistry that is used in interfacial polymerization, discusses the (dis)advantages of derived material types, and assesses the future prospects for synthesis of ultrathin functional materials via interfacial polymers.
Abstract: Interfacial polymerization is an enabling technique for the large-scale production of ultrathin layers, hollow nanospheres and nanofibers. The availability of a wide range of suitable monomer reactants allows for the synthesis of an impressive collection of polymers, including polyamides, polyurethanes, polyureas, polyanilines, polyimides, and polycarbonates. In addition, the technique has been used to prepare defect-free, ultrathin films of metal organic frameworks, organic-inorganic hybrids, and bio-hybrids. This review provides an overview of the chemistry that is used in interfacial polymerization, discusses the (dis)advantages of derived material types, and assesses the future prospects for synthesis of ultrathin functional materials via interfacial polymerization.
252 citations
Patent•
28 Mar 2011TL;DR: In this paper, a composite semipermeable membrane is proposed, which comprises a separation functional layer on a microporous support, and in which the functional layer is made of a condensation product of a polymer that has acidic groups and a trialkoxysilane groups having an imidazolium structure in side chains.
Abstract: Disclosed is a composite semipermeable membrane, which comprises a separation functional layer on a microporous support, and in which the separation functional layer is made of a condensation product of a polymer that has acidic groups and a trialkoxysilane groups having an imidazolium structure in side chains. The composite semipermeable membrane has excellent selective separation performance for divalent ions over monovalent ions, while exhibiting excellent long-term durability. Also disclosed is a method for producing the composite semipermeable membrane. The composite semipermeable membrane is suitable for uses in various water treatment fields such as the desalination of seawater and the production of drinking water. In addition, the composite semipermeable membrane does not deteriorate as much as conventional composite semipermeable membrane even in cases where the membrane is sterilized by having chlorine-containing raw water permeate therethrough continuously or intermittently.
71 citations
52 citations
TL;DR: In this paper, hyperbranched polyester (HPE) was selected as the nano-sized macromonomer and successfully incorporated into the skin layers on PVC hollow fiber substrates via interfacial polymerization between trimesoyl chloride and the mixtures of hydroxyl-terminated HPE/piperazine (PIP).
Abstract: To prepare thin film composite (TFC) nanofiltration (NF) membranes with improved flux and rejection performance at low pressure, hyperbranched polyester (HPE) was selected as the nano-sized macromonomer and successfully incorporated into the skin layers on PVC hollow fiber substrates via interfacial polymerization between trimesoyl chloride and the mixtures of hydroxyl-terminated HPE/piperazine (PIP). The resultant NF membranes were characterized using ATR-FTIR, FESEM, AFM and surface zeta potential, while their performance was evaluated in terms of permeate flux and rejection rates of different inorganic salts and neutral solutes. When the HPE content was lower than 60 wt% in HPE/PIP mixtures, the increased membrane surface roughness and the HPE embedded in skin layer effectively enhanced the permeate flux without sacrificing salt rejection for the prepared TFC NF membranes. Further increasing HPE content in HPE/PIP mixtures yielded looser polyamide skin layer, which led to the decline of solute rejection. Due to the larger size and good interfacial compatibility with cross-linked polyamide matrix, the incorporated HPE could exist stably in the skin layer. And thus, the prepared TFC NF membranes showed good flux and rejection stability in a long-term filtration process.
51 citations
References
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TL;DR: A review of the field of thin film composite reverse osmosis membranes, with emphasis on the chemistry and composition of these membranes, is given in this article, with particular attention given to composite membranes that have found commercial use, whether in the present or past.
Abstract: This is a review of the field of thin film composite reverse osmosis membranes, with emphasis on the chemistry and composition of these membranes. Particular attention is given to composite membranes that have found commercial use, whether in the present or past. Applications of composite reverse osmosis membranes in actual separation is only briefly treated
1,627 citations
"Separation Behavior of Composite Po..." refers background in this paper
...It is reported (1) that the interfacial reaction occurs in the organic layer, particularly when monomeric diamines are used....
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...Peterson (1) gave a detailed review of composite Reverse Osmosis (RO) and Nanofiltration (NF) membranes....
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...accelerate the metaphenylene diamine (MPD)–trimesoyl chloride (TMC) reaction by removing hydrogen halides formed during amide bond formation (1)....
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...Sodium hydroxide, sodium tertiary phosphate, dimethyl piperazine, triethylamine (TEA), and other acylation catalysts accelerate the MPD– TMC reaction by removing hydrogen halides formed during amide bond formation (1)....
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TL;DR: In this paper, the impacts of organic solvent properties, reaction conditions, and curing conditions on polyamide composite reverse osmosis membrane separation performance, film structure, and interfacial properties are reported.
Abstract: Here we report on the impacts of organic solvent properties, reaction conditions, and curing conditions on polyamide composite reverse osmosis membrane separation performance, film structure, and interfacial properties. We provide direct experimental evidence that: (1) MPD diffusivity in the organic phase governs MPD–TMC thin film water permeability, (2) MPD diffusivity and solubility influence MPD–TMC thin film crosslinking in competing ways, (3) water permeability correlates most strongly with MPD–TMC film structure (i.e., crosslinking), and (4) salt rejection correlates most strongly with MPD–TMC film thickness and morphology. Overall, higher flux membranes with good salt rejection appear to comprise thinner, more heavily crosslinked film structures. Such high performance RO membranes are obtained by (1) selecting high surface tension, low viscosity solvents, (2) controlling protonation of MPD and hydrolysis of TMC during interfacial polymerization, and (3) optimizing curing temperature and time based on organic solvent volatility. Finally, although more research is necessary, our results suggest the rugose morphology and relative hydrophobicity of high performance MPD–TMC membranes might enhance concentration polarization and exacerbate surface fouling.
736 citations
"Separation Behavior of Composite Po..." refers background in this paper
...Recently it has been reported that on addition of triethyl amine (TEA) and organic acids like camphor sulfonic acid (CSA) in an aqueous solution of MPD, pure water permeability dramatically increases, salt rejection is practically unchanged, the contact angle is slightly reduced, and roughness is significantly reduced in TFC membranes (16)....
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Patent•
22 Feb 1979
TL;DR: Good salt rejection and flux characteristics can be obtained with reverse osmosis membranes made from crosslinked, interfacially polymerized aromatic polyamides, particularly poly(arylenepolyamine aromatic polycarboxylamides) such as poly(phenylenediamine trimesamide) as discussed by the authors.
Abstract: Good salt rejection and flux characteristics can be obtained with reverse osmosis membranes made from crosslinked, interfacially polymerized aromatic polyamides, particularly poly(arylenepolyamine aromaticpolycarboxylamides) such as poly(phenylenediamine trimesamide). The aromatic polyamides are preferably synthesized directly from an essentially monomeric polyacyl halide (at least tri- or higher in acyl functionality) and an essentially monomeric arylene polyamine with a measurable water solubility. As compared to closely analogous linear polymers, these interfacially polymerized, crosslinked polyamides have a lower % elongation and lower solubility (e.g. in amide solvents). Chlorine resistance characteristics of these polyamides are also good and can be improved by treatment with a chlorinating agent. In the preferred practice of the method for making a reverse osmosis membrane, a porous support layer is coated with the polyamine component (e.g. an aqueous solution of phenylene diamine); the thus-coated support is contacted with the polyacyl halide component (e.g. trimesoyl chloride), thereby initiating the interfacial polymerization in situ on the support; and the resulting product is dried to provide a composite membrane comprising the polyamide laminated to the porous support.
537 citations
TL;DR: The combined results of AFM, XPS, and solid-state NMR provided a robust explanation for the mechanism of flux enhancement of the aromatic polyamide T FC membranes with the addition of DMSO, which would contribute to not only a fundamental understanding of the process but also an advanced designing of the so-called "tailor-fit" TFC membranes.
Abstract: The present paper explores the role of dimethyl sulfoxide (DMSO) used as an additive to modify the morphological as well as the molecular nature of aromatic polyamide during the formation of thin-film-composite (TFC) membranes. In addition, it elucidates the mechanism of enhancing the reverse osmosis (RO) permeation of the resulting membranes in proportion to the addition of DMSO. Morphological studies by atomic force microscopy (AFM) observed that as the concentration of DMSO increased, the surface roughness and the surface area of the aromatic polyamide TFC membranes became higher and larger, compared to FT-30 membrane for which DMSO was not added during interfacial reaction. Such morphological changes were brought about from fluctuating interface through reducing the immiscibility between aqueous/organic phases by DMSO and provided more opportunities to have contact with water molecules on the surface, participating in the enhancement of the water permeability. Chemical composition studies by X-ray photoelectron spectroscopy (XPS) revealed that there was a considerable increase of the cross-linked amide linkages relative to the linear pendant carboxylic acid groups in the TFC membranes of more DMSO addition. The increase of such amide linkages as hydrogen bonding sites facilitated the diffusion of water molecules through the thin films and played a favorable role in elevating water flux without considerable loss of salt rejection. Relaxation and motion analyses by 1H solid-state nuclear magnetic resonance (NMR) spectroscopy also confirmed the XPS revelation on the basis of measurements of the spin-lattice relaxation time in the rotating frame, T1rho, and determination of the correlation time, tau(c), for the aromatic polyamides forming thin films. The trend of longer tau(c)'s with the increase of DMSO concentration reflected the thin-film aromatic polyamides of less locally mobile chains, accompanied by the higher degree of cross-linking and, hence, the greater number of amide groups. The combined results of AFM, XPS, and solid-state NMR provided a robust explanation for the mechanism of flux enhancement of the aromatic polyamide TFC membranes with the addition of DMSO, which would contribute to not only a fundamental understanding of the process but also an advanced designing of the so-called "tailor-fit" TFC membranes.
212 citations
"Separation Behavior of Composite Po..." refers methods in this paper
...For example, adding dimethyl sulfoxide (DMSO) to the aqueous amine solution improves water flux by formation of a thinner and rough polyamide film (15)....
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Patent•
09 Apr 2001TL;DR: In this paper, a composite membrane and method for making the same, comprising a porous support and a polyamide surface, is presented, which is easily adapted to commercial scale manufacturing processes and is particularly suited for making nanofiltration and reverse osmosis composite membranes.
Abstract: A composite membrane and method for making the same, comprising a porous support and a polyamide surface. The subject membrane provides improved flux and/or rejection rates. The subject membrane is further capable of operating at lower operating pressures. The subject method includes reacting a polyfunctional amine with a polyfunctional acyl halide to form a polyamide. The method includes the step of contacting a complexing agent with the polyfunctional acyl halide prior subtantial reaction between the polyfunctional acyl halide and a polyfunctional amine. The subject process is easily adapted to commercial scale manufacturing processes and is particularly suited for making nanofiltration and reverse osmosis composite membranes.
198 citations