A selective membrane having a high fouling resistance. In one embodiment, the selective membrane is a composite polyamide reverse osmosis membrane in which a hydrophilic coating is applied to the polyamide layer of the membrane, the hydrophilic coating being made by covalently bonding a hydrophilic compound to residual acid chlorides of the polyamide membrane, the hydrophilic compound including (i) at least one reactive group that is adapted to covalently bond directly to the polyamide membrane, the at least one reactive group being at least one of a primary amine and a secondary amine; and (ii) at least one hydrophilic group, the at least one hydrophilic group being selected from the group consisting of a hydroxyl group, a carbonyl group, a trialkoxysilane group, an anionic group and a tertiary amino group; (iii) wherein the hydrophilic compound is devoid of a polyalkylene oxide group.

Selective membrane having a high fouling resistance

A composite polyamide reverse osmosis membrane and method of producing same. In a preferred embodiment, the membrane is made by coating a porous polysulfone support with an aqueous solution containing 2 wt % m-phenylenediamine (MPD), and 0.1 wt % di(ethylene glycol) hexyl methyl ether. Next, the excess solution is removed, and the coated support is dipped in 0.1 wt % organic solvent solution of trimesoyl chloride (TMC) in a mixture of alkanes having from 8 to 12 carbon atoms. After draining the TMC solution off, the resulting composite membrane is air dried and then rinsed in a basic aqueous solution. The resultant membrane exhibits a flux of 21.3 gfd and a salt rejection of 98.9% when used at 225 psi for an aqueous solution containing 2000 ppm of NaCl.

Composite polyamide reverse osmosis membrane and method of producing the same

A filter for removing microorganisms from a fluid is provided by the invention. The filter includes a substrate having a reactive surface, and a polymer covalently bonded to the reactive surface of the substrate. The polymer includes a plurality of cationic groups for attracting microorganims. Faucet mounted filters and pour through filters containing the polymer coated substrate are provided. Also disclosed are methods for using and manufacturing filters for removing microorganisms from a fluid.

Microorganism filter and method for removing microorganism from water

An interfacial polymerization process (IFP) for preparing a highly permeable TFC RO membrane by contacting on a porous support membrane for IFP, a polyfunctional acyl halide monomer and a polyamine monomer and recovering a highly permeable thin film (TFC) reverse osmosis (RO) membrane. At least one of solutions may contain nanoparticle additives which may release ions into solution and at least one of the solutions may contain additional ions from a second additive. The presence of the nanoparticle additives during IFP may increase the hydrophilicity and/or permeability of the recovered membrane compared to a control membrane. The presence of the additional ions from the second additive may also increase the permeability of the recovered membrane.

Reverse osmosis membranes

A reverse osmosis composite membrane that has a high salt rejection, a high water permeability, and a high fouling tolerance, and permits practical desalination at a relatively low pressure is provided by coating the surface of a reverse osmosis membrane of aromatic polyamide with polyvinyl alcohol (PVA), for example, and controlling the surface zeta potential of the separation layer within±10 mV at pH 6. This reverse osmosis composite membrane is electrically neutral and controls the electrical adsorption of membrane-fouling substances having a charge group present in water. Therefore, a high separation property can be maintained without fouling the membrane even if water containing a surfactant or a transition metal component is supplied as raw water.

Composite reverse osmosis membrane having a separation layer with polyvinyl alcohol coating and method of reverse osmotic treatment of water using the same

Semipermeable membranes of a porous polymeric substrate whose external and all internal surfaces (pores) are encapsulated by a semipermeable thin film of a hydrophilic polymer are provided. The encapsulating film consists of at least one layer of said polymer which is cross-linked/stabilized by polyfunctional compounds containing at least two functional (reactive) groups. The membrane substrate is optionally pretreated--before the encapsulation step--with polyfunctional compounds. The new membranes can be used in ultrafiltration and reverse osmosis processes. They are solvent-, pressure- and temperature-resistant and show good separation capacities, e.g. for separating organic compounds from salt solutions.

Semipermeable encapsulated membranes, process for their manufacture and their use

Semipermeable Kompositmembran aus einem porosen, polymeren Substrat und beschichtet mit einem dunnen semipermeablen Film, der alle ausseren und zuganglichen inneren Oberflachen des Substrats bedeckt und aus mindestens einer Schicht eines vernetzbaren hydrophilen Polymers besteht, die mit mindestens einer polyfunktionellen Verbindung mit mindestens zwei funktionellen Gruppen vernetzt ist, wobei das Substrat gegebenenfalls mit einer polyfunktionellen Verbindung mit mindestens zwei funktionellen Gruppen vorbehandelt ist. Semipermeable composite membrane from a porous polymeric substrate and coated with a thin semi-permeable film that covers all external and accessible internal surfaces of the substrate and consisting of at least one layer of a crosslinkable hydrophilic polymer which is crosslinked with at least one polyfunctional compound having at least two functional groups wherein the substrate is optionally pretreated with a polyfunctional compound having at least two functional groups. Die neuen Membranen sind zB in einem weiten Temperaturbereich sowie gegen Losungsmittel stabil. The new membranes are eg stable in a wide temperature range and to solvents. Sie besitzen eine ausgezeichnete Trennkapazitat und sind zB geeignet, um organische Verbindungen aus Salzlosungen abzutrennen. They have excellent separation capacity and are suitable, for example, to separate organic compounds from salt solutions.

Kotraro Reuven

Papers

Semipermeable encapsulated membranes, process for their manufacture and their use

Semi-permeable encapsulated membranes, process for their production and their use