Ultrathin membranes for gas separation and pervaporation prepared upon electrostatic self-assembly of polyelectrolytes

Ackern, Frank van; Krasemann, Lutz; Tieke, Bernd

doi:10.1016/s0040-6090(98)00782-2

Cited by 115 publications

(100 citation statements)

References 11 publications

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“…This is because the exposure of membranes to low pH controls the degree of ionization of the polar groups [2][3][4][5][6][7]. After HCl treatment, the more -COO-Na groups converted into the carboxyl acid, which would lead to the poor ionization of hydrolyzed PAN membranes and in turn to weaken the binding ability of PAN support.…”

Section: Effect Of Exposure Of Membranes To Low Phmentioning

confidence: 99%

“…investigated the molecular structure of polyelectrolytes, molecular weight of polyelectrolytes, number of deposited layer pairs, pH value, ionic strength and various other factors influencing the multilayer growth and pervaporationn performances [2][3][4][5][6][7]. The studies of Tieke et al [2][3][4][5][6][7] showed that a significantly large number of depositions of anionic/cationic polyelectrolytes are needed in order to achieve a high selectivity.…”

Section: Introductionmentioning

confidence: 99%

“…The studies of Tieke et al [2][3][4][5][6][7] showed that a significantly large number of depositions of anionic/cationic polyelectrolytes are needed in order to achieve a high selectivity. It was noted that as many as 60 bilayers had to be deposited to obtain membranes with sufficient properties in LBL adsorption process.…”

Section: Introductionmentioning

confidence: 99%

“…Basically, in order to obtain long-term stability of self-assembled pervaporation membrane, the support membranes should be treated by chemical/physical methods to achieve negative or positive charges before deposition. Tieke's group has usually used oxygen plasma to treat the support membranes such as PAN/PET (a polyethyleneterephthalate fleece coated with a thin layer of polyacrylonitrile) [2][3][4][5][6][7]. Zhu et al selected the polyacrylonitrile (PAN) ultrafiltration membrane hydrolyzed with sodium hydroxide as the support membrane.…”

Section: Introductionmentioning

confidence: 99%

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Self-assembly of polyelectrolyte multilayer pervaporation membranes by a dynamic layer-by-layer technique on a hydrolyzed polyacrylonitrile ultrafiltration membrane

Zhang

Yan

et al. 2007

Journal of Membrane Science

141

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This paper is concerned with the self-assembly of polyelectrolyte multilayer membranes (PEMMs) by using dynamic layer-by-layer (LBL) adsorption technique for pervaporation separation of water/alcohol mixtures. The polyacrylonitrile (PAN) ultrafiltration membrane used as a support was firstly hydrolyzed with alkaline solutions followed by alternatively depositing polyethyleneimine (PEI) and polyacrylic acid (PAA) under a pressure of 0.1 MPa. The PEI-ethanol solution and PEI-aqueous solution were used to investigate the effects of solvents on the assembly process. It was found that both separation factor and permeate flux were improved remarkably by replacing PEI aqueous solution with PEI-ethanol solution. Because only a few composite bilayers were needed to achieve a good capability in the dynamic LBL process, the hydrolysis degrees of PAN support membrane would strongly affect the pervaporation membrane performances. It was also noted that the exposure of membranes to low pH after hydrolysis would not benefit for the assembly. Further studies were conducted to investigate the effects of alkali species on the PAN hydrolysis and pervaporation performances of PEMMs. The contribution of alkali species on the pervaporation performance was in the order of KOH > NaOH > LiOH. Finally, the performances of PEI/PAA multilayer membranes assembled on the hydrolyzed PAN support were evaluated with a relatively wide range of feed temperature and concentration. The PEMMs obtained with only 2.5 bilayers had a separation factor of 604 and a permeate flux of 314 g/m 2 h (70 • C) for pervaporation of 95 wt% ethanol-water mixture.

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Section: Effect Of Exposure Of Membranes To Low Phmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Self-assembly of polyelectrolyte multilayer pervaporation membranes by a dynamic layer-by-layer technique on a hydrolyzed polyacrylonitrile ultrafiltration membrane

Zhang

Yan

et al. 2007

Journal of Membrane Science

141

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“…The use of FEM method allows mass conservation in the domain; therefore "numerical loss" of mass in the computational domain is not a major concern. The applicability, validity and robustness of the FEM method for the kind of domain encountered in the present work were proved by a number of previous authors [20][21][22][23][24][25] . The FEM was combined with adaptive meshing and error control using numerical solver of UMFPACK.…”

Section: Numerical Solution Of the Model Equationsmentioning

confidence: 53%

Modeling of Organic Mixtures Separation in Dense Membranes Using Finite Element Method (FEM).

Marjani¹,

Shirazian²

2012

Orientjchem.

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A comprehensive mathematical model was developed to predict separation of organic mixtures using dense polymeric membranes. The organic mixture considered in this study was toluene and n-heptane mixture. The separation process was pervaporation (PV) which utilizes a dense membrane for separation. Conservation equations including continuity and energy transfers were solved numerically. Computational fluid dynamics (CFD) technique was used to solve the model equations. The toluene mole fraction and temperature profile were determined. The simulation results confirmed that the developed model can provide a general simulation for separation of organic mixtures using pervaporation.

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Highly Efficient Composite Membranes for Ethanol-Water Pervaporation

Krasemann

Tieke

2000

Chem. Eng. Technol.

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Composite membranes with ultrathin separation layer were prepared by alternate adsorption of cationic and anionic polyelectrolytes onto porous support membranes. The utility of these membranes for ethanol-water pervaporation was investigated. It was found that the separation capability is highest if polyelectrolytes with high charge density, such as polyethyleneimine (PEI) and polyvinylsulfate (PVS), are used. Under optimum conditions, the PEI/PVS separation layer is highly efficient in water enrichment in the permeate. A separation factor a up to 1000 could be detected, the flux simultaneously being 590 g/m 2 h. Effects of annealing of the membrane and change of the pervaporation temperature are also discussed.

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Ultrathin membranes for gas separation and pervaporation prepared upon electrostatic self-assembly of polyelectrolytes

Cited by 115 publications

References 11 publications

Self-assembly of polyelectrolyte multilayer pervaporation membranes by a dynamic layer-by-layer technique on a hydrolyzed polyacrylonitrile ultrafiltration membrane

Self-assembly of polyelectrolyte multilayer pervaporation membranes by a dynamic layer-by-layer technique on a hydrolyzed polyacrylonitrile ultrafiltration membrane

Modeling of Organic Mixtures Separation in Dense Membranes Using Finite Element Method (FEM).

Highly Efficient Composite Membranes for Ethanol-Water Pervaporation

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