ADDITIVES FOR SALT REJECTION ENHANCEMENT OF A MEMBRANE

摘要

Provided is an interfacial polymerization process for preparation of a thin film composite membrane, which can be used for nanofiltration, forward osmosis, or reverse osmosis, particularly for use with brackish water or seawater. The process includes contacting a porous support membrane with an aqueous phase containing a polyamine to form a coated support membrane, and applying an organic phase containing a polyfunctional acyl halide to the coated support membrane to interfacially polymerize the polyamine and the polyfunctional acyl halide to form a discrimination layer of a thin film composite membrane, where during formation of the membrane, the polyfunctional acyl halide is purified in situ by removal of hydrolyzed acyl halide through addition of a salt rejection-enhancing additive that includes a biguanide compound, dicarbonate compound, pentathiodicarbonate compound, or salt thereof. Also provided are the membranes prepared by the methods and reverse osmosis modules containing the membranes.

主权项

1. A process for preparing a thin film composite membrane, comprising:
providing an aqueous phase comprising a polyamine and an organic phase comprising a polyfunctional acyl halide; introducing a salt rejection-enhancing additive in the aqueous phase, the salt rejection-enhancing additive able to form a complex with hydrolyzed polyfunctional acyl halide; applying the aqueous phase to a surface of a porous support membrane to form a coated support membrane; applying the organic phase to the coated support membrane to allow interfacial polymerization between the aqueous phase and organic phase, wherein hydrolyzed and non-hydrolyzed polyfunctional acyl halide are present during interfacial polymerization; forming a complex between the salt rejection-enhancing additive and the hydrolyzed polyfunctional acyl halide and interfacially polymerizing the polyamine and the non-hydrolyzed acyl halide to produce a discrimination layer of a thin film composite membrane comprising the porous support membrane and the discrimination layer, wherein the thin film composite membrane exhibits a salt rejection that is greater than the salt rejection of a thin film composite membrane prepared in the absence of the salt rejection-enhancing additive or a permeability coefficient (B-value) that is less than the permeability coefficient of a thin film composite membrane prepared in the absence of the salt rejection-enhancing additive.