Hollow fiber composite membrane of ultrathin active layer and preparation method thereof

Abstract

The invention belongs to the field of functional polymer materials, and concretely relates to a hollow fiber composite membrane of an ultrathin active layer and a preparation method thereof. The hollow fiber composite membrane employs a polymer porous membrane whose internal surface and/or external surface is provided with a compact skin as a base membrane, and a hydrophilic material with selecting function is loaded on an external wall of the base membrane as an active separating layer. The thickness of the active separating layer is 0.2-1[mu]m. The invention also provides a preparation method of the composite membrane. The preparation process is simple and easy to operate; the composite membrane has high selectivity; the composite membrane has low preparation cost and is easy to realizeindustrial production. The thickness of the active separating layer on the surface of the composite membrane is ultra thin, usage amount is low, and the method is suitable for industrial production; the active layer of the hollow fiber composite membrane is compact without defects, the preparation method is simple, and the thickness is controllable.

Description

technical field [0001] The invention belongs to the field of functional polymer materials, and in particular relates to a hollow fiber composite membrane with an ultra-thin active layer and a preparation method thereof. Background technique [0002] Gas membrane separation is a process of realizing gas separation by using the different dissolution and diffusion properties of the components in the mixture gas in the dense membrane. In order to improve the permeability of the membrane, it is usually prepared as a composite membrane, that is, the microporous base membrane is covered with an ultra-thin surface layer with nano-pore size, and the separation effect of the composite membrane is mainly or completely determined by the ultra-thin skin layer. The thinnest composite membrane skin can reach several nanometers, so the membrane has high flux. In addition, the surface layer of the composite film is ultra-thin, that is, the amount of materials is very small, and high-molecul...

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Problems solved by technology

The polymer composite hollow fiber microporous membrane prepared by Zenon Corporation of Canada (US Patent No.5,472,607, US2003 / 009827 5A1, WO 00 / 78437 A1) has a thickness of 0.01-0.1mm, and the membrane thickness is thicker than ultra-thin; Although the water flux of the membrane has been significantly improved, the polymer separation membrane is poorly bonded to the base membrane. During the reverse cleaning process of the membrane, the polymer separation membrane is prone to peeling off and has low anti-stripping performance.

U.S. Patent (US Pat.4857080) reported a "three-layer composite membrane using silicon rubber-palladium alloy-polymer microporous support layer" for separating and purifying hydrogen. Although the defects of the palladium alloy were reduced, the penetration of the composite membrane The rate is reduced, so the separation performance of the membrane is low

T.A.Peters et al [T.A.Peters, C.H.S.Poeth, N.E.Benes, H.C.W.M.Buijs, F.F.Vercauteren, J.T.F.Keurentjes.Journal of Membrane Science 276(2006) 42-50] reported the polyvinyl alcohol pervaporation membrane supported by hollow fiber ceramics, using 300nm macroporous inorganic ceramic hollow fiber support, modified 4 times with boehmite solution to form γ-Al 2 o 3 The intermediate transition layer, finally prepared a film layer with a pore size of 4nm and no defects, the production process is too complicated

[0004] Existing gas separation membranes generally have disadvantages such as low permeation, small separation factor and poor mechanical strength.

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