Membranes, methods of making the membranes, and methods of using the membranes are described herein. The membranes can comprise a gas permeable support layer, an inorganic layer disposed on the support, the inorganic layer comprising a plurality of discreet nanoparticles having an average particle size of less than 1 micron, and a selective polymer layer disposed on the inorganic layer, the selective polymer layer comprising a selective polymer having a CO.sub.2:N.sub.2 selectivity of at least 10 at 57 C. In some embodiments, the membrane can be selectively permeable to an acidic gas. The membranes can be used, for example, to separate gaseous mixtures, such as flue gas.

A separation portion for use in an apparatus for reducing the ratio of divalent ions to a monovalent ion in an aqueous solution from a source aqueous solution that contains a higher ratio of divalent ions to the target monovalent ion. The separation portion includes a membrane having a membrane substrate and a coating arranged over at least a part of the membrane substrate. An apparatus including the separation portion and a process for reducing the ratio of divalent ions to a monovalent ion in an aqueous solution.

Provided is an interfacial polymerization process for preparation of a highly permeable thin film composite membrane, which can be used for nanofiltration, or forward or reverse osmosis, for use with tap water, seawater and brackish water, particularly for use with brackish water at low energy conditions. The process includes contacting a porous support membrane with an aqueous phase containing a polyamine and a flux enhancing combination, which includes a metal chelate additive containing a bidentate ligand and a metal atom or metal ion and a dialkyl sulfoxide, to form a coated support membrane, and applying an organic phase containing a polyfunctional acid halide to the coated support membrane to interfacially polymerize the polyamine and the polyfunctional acid halide to form a discrimination layer of the thin film composite membrane. Also provided are the membranes prepared by the methods and reverse osmosis modules containing the membranes.

Provided is an interfacial polymerization process for preparation of a highly permeable 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 acid halide to the coated support membrane to interfacially polymerize the polyamine and the polyfunctional acid halide to form a discrimination layer of a thin film composite membrane, where the aqueous and/or organic phases include a flux-enhancing additive and a boron rejection-enhancing additive that includes a biguanide compound, dicarbonate compound, pentathiodicarbonate compound, or salts thereof. Also provided are the membranes prepared by the methods and reverse osmosis modules containing the membranes.

An apparatus for reducing the ratio of divalent ions to a monovalent ion in an aqueous solution from a source aqueous solution that contains a higher ratio of divalent ions to the target monovalent ion. The apparatus includes an optional prefiltration portion operable to receive the source aqueous solution and produce a prefiltered aqueous solution, a first separation portion, such as a nanofiltration separation portion, operable to receive the optionally prefiltered aqueous solution and form an intermediate aqueous solution having a lower ratio of divalent ions to the target monovalent ion than the prefiltered aqueous solution; and a second separation portion, such as an ion-exchange separation portion, operable to receive the intermediate aqueous solution and form a product aqueous solution having a lower ratio of the divalent ions to the target monovalent ion than the intermediate solution.

The present invention relates to improved methods for synthesis of thin film composite membranes by interfacial polymerization. More in particular, the method of the present invention comprises the impregnation of an ultrafiltration porous support membrane with an aqueous solution containing a polyfunctional nucleophilic monomer, and contacting the impregnated support membrane with a second largely water-immiscible solvent containing a polyfunctional epoxide monomer.

Provided is an interfacial polymerization process for preparation of a highly permeable 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 acid halide to the coated support membrane to interfacially polymerize the polyamine and the polyfunctional acid halide to form a discrimination layer of a thin film composite membrane, where the aqueous and/or organic phases include a flux-enhancing additive and a boron rejection-enhancing additive that includes a biguanide compound, dicarbonate compound, pentathiodicarbonate compound, or salts thereof. Also provided are the membranes prepared by the methods and reverse osmosis modules containing the membranes.

Electrically conductive membranes (ECMs) have been demonstrated in the literature as a promising tool to enhance the performance of membrane-based water/wastewater treatment technologies. Membrane surface functionalization with active conductive materials is a direct and effective approach to obtain membranes with electrically conductive properties. However, a general strategy that could be utilized to fabricate ECMs using any types of commercial membrane (e.g., reverse osmosis, nanofiltration, ultrafiltration, and microfiltration) as a support or any type of conductive material as active material is not available yet. To address this need, the subject matter described herein is a facile and low-cost polyethyleneimine/glutaraldehayde-based method for synthesis of electrically conductive membranes starting from a broad range of commercial membranes (i.e., SWC4+, ESPA3, NF 270, PSf 20 KDa, and 0.1 m PVDF membranes) by using graphite or other conductive materials, including but not limited to, carbon nanotubes, activated charcoal, reduced graphene oxide, and silver nanoparticles.

Provided are flux enhancing inclusion complexes for preparing highly permeable thin film composite membranes, and processes that include adding the flux enhancing inclusion complexes to the organic phase or aqueous phase prior to interfacial polymerization of the thin film composite membrane. The thin film composite membranes are suitable for nanofiltration, and reverse and forward osmosis. The provided processes can include 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 acid halide and a flux enhancing inclusion complex to the coated support membrane to interfacially polymerize the polyamine and the polyfunctional acid halide to form a discrimination layer to form thin film composite membranes.

Disclosed herein are transition and/or heavy metal cation-capturing membranes constructed from zinc imidazole salicylaldoxime (ZIOS) nanosheets deposited on membrane supports, and methods of making and using such metal cation-capturing membranes. In a non-limiting embodiment, the membrane support comprises polyvinylidene fluoride (PVDF) membranes which have been modified with polydopamine (PDA) and polyethyleneimine (PEI). Three exemplary methods for fabricating the metal cation-capturing membranes include (1) in-solution hydrothermal growth, (2) vacuum-assisted coordination growth, and (3) interfacial coordination growth methods. The membranes may be tuned regarding textural properties and the adhesion of the ZIOS to the membrane support.