# US 5,266,207 A · Composite nanofiltration membrane > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,266,207 A - Document ID: US5266207A - Status: Granted - Kind: A - Application number: 07/876,441 - Filed: 1992-04-30 - Granted: 1993-11-30 - Earliest claimed: 1991-04-30 - Assignees: Techsep - Inventors: Anne Boye; Andre Grangeon; Christian Guizard - Web page: https://patentgrep.com/patent/US5266207A ## CPC - B01D 71/72: Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of the groups B01D71/46 - B01D71/70 {and B01D71/701 - B01D71/702} - B01D 69/108: {Inorganic support material} - B01D 69/1214: {Chemically bonded layers, e.g. cross-linking} - C08G 79/025: Polyphosphazenes - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS ## Abstract Mechanically strong and thermally/chemically-resistant composite nanofiltration membranes, well adapted for the separation of low molecular weight compounds, comprise a porous inorganic support substrate, the pore diameters of which ranging from 3 to 10 nm, this inorganic support substrate having a polymer membrane which comprises an elastomeric polyphosphazene densely deposited on at least one of the face surfaces thereof, the structural porosity of such polyphosphazene membrane ranging from 0.2 to 2 nm. ## Claims ### Claim 1 A composite nanofiltration membrane comprising a porous inorganic support substrate, said substrate having face surfaces and having pore diameter ranging of from 3 to 10 nm, a polymer membrane which comprises an elastomeric polyphosphazene densely deposited on at least one of the face surfaces thereof, the structural porosity of said polyphosphazene membrane ranging from 0.2 -2 nm. ### Claim 2 (depends on 1) The composite nanofiltration membrane as defined by claim 1, wherein said polyphosphazene membrane is nested within the pores of said inorganic support substrate and/or providing a continuous coating layer thereon. ### Claim 3 (depends on 2) The composite nanofiltration membrane as defined by claim 2, wherein said microporous polyphosphazene membrane has a thickness ranging from 0.1 to 10 .mu.m. ### Claim 4 (depends on 1) The composite nanofiltration membrane as defined by claim 1, wherein said inorganic support substrate comprises a macroporous metal or metallic alloy support having at least one inorganic membrane layer deposited onto at least one of the face surfaces thereof. ### Claim 5 (depends on 4) The composite nanofiltration membrane as defined by claim 4, wherein said at least one inorganic membrane layer comprises a metal oxide. ### Claim 6 (depends on 5) The composite nanofiltration membrane as defined by claim 5, wherein said metal oxide comprises beryllium, magnesium, calcium, aluminum, titanium, strontium, yttrium, lanthanum, zirconium, hafnium, thorium, iron, manganese or silicon. ### Claim 7 (depends on 6) The composite nanofiltration membrane as defined by claim 6, wherein said macroporous support comprises nickel, steel, carbon or a ceramic material. ### Claim 8 (depends on 1) The composite nanofiltration membrane as defined by claim 1, wherein said membrane is tubular. ### Claim 9 (depends on 1) The composite nanofiltration membrane as defined by claim 1, wherein said microporous polyphosphazene membrane has a structural porosity ranging from 0.8 to 1.5 nm. ### Claim 10 (depends on 1) The composite nanofiltration membrane as defined by claim 1, wherein said elastomeric polyphosphazene has the formula: ##STR13## in which the radicals R.sub.1, which may be identical or different, each have the formula: ##STR14## in which R.sub.2 and R.sub.3, which may be identical or different, are each a linear or branched aliphatic hydrocarbon radical having from 1 to 12 carbon atoms, a cycloalkyl radical having from 3 to 8 carbon atoms, an aryl, alkylaryl or aralkyl radical having from 6 to 18 carbon atoms and the alkyl moiety of which having from 1 to 4 carbon atoms or a heterocycle having from 3 to 20 carbon atoms, the heteroatoms of which comprising O, S and N, with the proviso that R.sub.2 and R.sub.3 may together form, with the nitrogen atom from which they depend, a heterocycle having from 3 to 15 carbon atoms and which may also include another O, S and N heteroatom; the radicals Y have the formula: ##STR15## in which the radicals R.sub.4, which may be identical or different, are each a hydrogen atom or a radical R.sub.2 or R.sub.3 ; Z is a divalent hydrocarbon radical having from 1 to 20 carbon atoms and which may include at least one O, N and S heteroatom, with the proviso that two radicals R.sub.4, may together form with Z, a heterocycle having from 3 to 15 carbon atoms; and n is an integer ranging from 10 to 30,000. ### Claim 11 (depends on 10) The composite nanofiltration membrane as defined by claim 10, wherein formula (1) R.sub.1 is diphenylamino, N-naphthyl-2-N-propylamino, aziridino, imidazolyl, pyrollyl, indolyl, pyrrolinyl, 2-imidazolinyl, piperidinyl, morpholino, dibutylamino, or quinolinyl. ### Claim 12 (depends on 10) The composite nanofiltration membrane as defined by claim 10, wherein formula (1) Y is selected from the group consisting of ##STR16## ### Claim 13 (depends on 10) The composite ultrafiltration membrane as defined by claim 10, wherein R.sub.1 is ##STR17## ### Claim 14 (depends on 1) The composite nanofiltration membrane as defined by claim 1, wherein said membrane has a molecular weight cutoff ranging from 100 to 1,000 daltons. ### Claim 15 In a process for separating an effluent of low molecular weight compounds by nanofiltration, the improvement comprising, using a composite nanofiltration membrane comprising a porous inorganic support having face surfaces, and a pore diameter ranging from 3 to 10 nm, and a polymer membrane comprising an elastomeric polyphosphazene densely deposited on at least one of said face surfaces thereof, the structural porosity of said polyphosphazene membrane ranging from 0.2-2 nm. ### Claim 16 (depends on 15) The process as defined by claim 15, including the step of varying the pressure of the effluent contacting said composite nanofiltration membrane.