Preparation method of ultra-low pressure contamination-resistance composite reverse osmosis membrane

Abstract

The invention discloses a method for preparing an ultralow pressure fouling resistant composite reverse osmosis membrane. A layer of hydrophilic matter is coated onto an ultralow pressure polyamide membrane. The method comprises the following steps: preparing and mixing a polyvinyl alcohol solution, a polyethylene imine solution and a crosslinking agent solution; spreading the mixture onto a polyamide carrier membrane; and obtaining the ultralow pressure fouling resistant composite reverse osmosis membrane after drying. The reverse osmosis membrane has high water flux, a high salt rejection capability and good fouling resistance under the ultralow pressure operation.

Description

technical field [0001] The invention belongs to the field of membrane water treatment, and in particular relates to a production method of a composite reverse osmosis membrane with anti-pollution performance that can be applied under ultra-low pressure. Background technique [0002] At present, the common reverse osmosis composite membrane is to form a layer of polyamide separation layer through interfacial polymerization on the non-woven polysulfone support layer (for example, Chinese Patent No. CN1724130A, Chinese Patent No. CN1370796A, etc.). [0003] Although the above-mentioned polyamide composite membrane has good separation performance and permeation performance, it cannot avoid the current membrane fouling problem, such as the decrease of the permeation flow due to the adsorption or attachment of suspended or dissolved substances on the membrane surface, due to Membrane fouling is a problem. In order to obtain a certain flow rate of permeate, the pressure must be adj...

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Problems solved by technology

[0005] For example, Chinese Patent Publication No. CN1213985A discloses a "reverse osmosis composite membrane and its method for reverse osmosis treatment of water", wherein the reverse osmosis composite membrane is a low-pollution composite reverse osmosis membrane, using PVA to coat polyamide layer surface, but because PVA molecules are not cross-linked, PVA is easy to gradually dissolve in water during the use of the membrane, and eventually loses its role as a separation layer

[0006] And Chinese patent publication number CN1923348A discloses a kind of " production method of low-pollution composite reverse osmosis membrane ", in this method, a layer of hydrophilicity is coated on the polysulfone support layer, and then a layer of polyamide separation layer is formed by interfacial polymerization , and finally coat a layer of hydrophilic material on the polyamide separation layer. Although this method solves the pollution resistance problem of the membrane to a certain extent, the operating pressure of the membrane is still the traditional brackish water treatment pressure ( 1.6MPa), there is not much improvement in energy saving

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