Separation of aqueous organic solvents through crosslinked poly(acrylate-co-acrylic acid) membranes by pervaporation.

ABSTRACT:It is desirable to enhance the selectivity of a polydimethylsiloxane (PDMS) membrane for chlorinated hydrocarbons. In this study, the PDMS membranes were improved by graft polymerization of 1H,1H,9H-hexadecafluorononyl methacrylate (HD-FNMA), which has the effect of increasing the selectivity for chlorinated hydrocarbons. The PDMS membrane and HDFNMA were irradiated simultaneously by a 60 Co source. The grafted membranes had a microphase-separated structure, that is, a separated structure of PDMS and grafted HDFNMA. In the grafted PDMS membrane, a great separation performance for a TCE-water mixture was shown due to the introduction of the hydrophobic polymer, poly(HDFNMA). For the permeation of the grafted PDMS membrane, the permeability of molecules in the PDMS phase was significantly great, and that in the poly(HDFNMA) phase was too low to affect the whole permeation of the grafted PDMS membrane directly. However, the permeation of molecules at the interface of poly(HDFNMA) and PDMS played an important role because poly(HDFNMA) had a much stronger affinity for TCE than water. At a low feed concentration of the TCE solution, the diffusivity of TCE molecules must be much lower than that of water due to the larger molecular size of TCE. At a high concentration of TCE solution, TCE was sufficiently sorbed into the membrane so that the diffusion of water was prevented by TCE molecules; in turn, the permselectivity of TCE was increased significantly.

Section: Introductionmentioning

confidence: 99%

Characterization and pervaporation of chlorinated hydrocarbon-water mixtures with fluoroalkyl methacrylate-grafted PDMS membrane

Mishima

Kaneoka

Nakagawa

1999

“…[7][8][9] The ethylacetate solution containing 20 -30 wt % polyurethane was coated on an exfoliatetreated polyethyleneterephthalate (PET) film and then dried at 100°C for 5 min. The polyurethane membrane was laminated with a porous polypropylene sheet, Celgard 2500, and the PET film was displaced with Celgard.…”

Section: Membrane Preparationmentioning

confidence: 99%

“…6 We have also reported on polyacrylate, polymethacrylate, and polyurethane membranes for organic solvent separation from dilute aqueous solutions by pervaporation. [7][8][9] For the organic solvent separation from dilute aqueous solutions, we have focused on the separation of phenol dilute aqueous solution for the following reason: the phenol is a raw material used for the synthesis of phenolic resin, bisphenol-A, and other chemicals. Because a large quantity of wastewater containing phenol has been produced, its effective disposal is needed.…”

Section: Introductionmentioning

confidence: 99%

Separation of aqueous phenol through polyurethane membranes by pervaporation. II. Influence of diisocyanate and diol compounds and crosslinker

Hoshi

Ieshige

Saitoh

et al. 1999

Self Cite

ABSTRACT:The influence of diisocyanate and diol compounds of polyurethane and crosslinking agent on the separation of phenol aqueous solution by pervaporation was investigated. Polyurethanes were prepared by polyaddition of diisocyanate and diol compounds and trimethylolpropane (TMP) using dibutyltindilaulate as a catalyst. The polyurethane membrane was prepared by a casting method and was sandwiched with a porous polypropylene membrane (Celgard 2500). Pervaporation measurement was carried out under vacuum on the permeate side, and the permeant was collected with a liquid nitrogen trap. Little influence of diisocyanate compounds on the phenol permselectivity through diisocyanate-polytetramethyleneglycol [PTMG(1000)] membranes was observed since the influence on the solubility and the diffusivity was small. The phenol permselectivity was increased with an increase in the molecular weight of PTMG and polycaprolactone diol (PCL) for the 1,6-diisocyanato hexane (HMDI)-PTMG and HMDI-PCL membranes. It was considered that the increase in phenol diffusivity can be attributed to an increase in phenol selectivity. The permeability and selectivity of HMDI-[PTMG(2900)-TMP] membrane was relatively constant below the 2% TMP content.

“…[13][14][15] In the previous work using polyacrylate or polymethacrylate, copolymer membranes of acrylic acid (AA), methacrylic acid (MA), and methyl methacrylate (MMA) were employed for water-permselective membranes. 16 -20 The polyacrylate and the polymethacrylate polymers, which contain a short hydrocarbon chain of an ester residue or a hydrophilic functional group, show water permselectivity and have a high glass transition temperature (T g ).…”

Section: Introductionmentioning

confidence: 99%

“…13,14 Consequently, it was expected that there would be an influence of the porous substrate on the permselectivity. For the separation of phenol in a polyurethane membrane, the dependence of the polyurethane layer thickness on the permselectivity was observed.…”

Section: Introductionmentioning

confidence: 99%

Pervaporation separation of 1,1,2-trichloroethane-water mixture through crosslinked acrylate copolymer composite membranes

Hoshi

Saitoh

Yoshioka

et al. 1999

Self Cite

ABSTRACT:The separation of a chlorinated hydrocarbon from a dilute aqueous solution through a crosslinked acrylate copolymer-porous substrate composite membrane by pervaporation was investigated. Poly(n-butyl acrylate-co-acrylic acid) and poly(n-butyl acrylate-co-2-hydroxyethyl acrylate) were synthesized and composite membranes were prepared, which were made from the crosslinked polymer and a porous substrate. Pervaporation measurement was carried out for a dilute aqueous solution of 1,1,2-trichloroethane at 25°C and under a vacuum on the permeate side (below 10 mmHg). The separation factor, overall flux, 1,1,2-trichloroethane concentration in the membrane, and the degree of swelling decreased with increase in the acrylic acid or 2-hydroxyethyl acrylate content of the acrylate copolymer. The influence of the crosslinking agent content on the pervaporation performance was small, and the separation factor and the overall flux showed a convex curve. The structure of the crosslinking agent had no effect on the separation. The influence of the pore size of the substrate and the thickness of the polymer layer on the separation of 1,1,2-trichloroethane was observed.