# US 6,596,173 B1 · Inorganic filtering material modified with organomineral grafting and preparation method

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- Number: US 6,596,173 B1
- Document ID: US6596173B1
- Status: Granted
- Kind: B1
- Application number: 09/555,842
- Filed: 2000-10-04
- Granted: 2003-07-22
- Earliest claimed: 1997-12-04
- Assignees: Orelis
- Inventors: Bernard Chaufer; Jun Kong Liou; Anne Bouguen; Murielle Rabiller-Baudry; Luc Millesime
- Web page: https://patentgrep.com/patent/US6596173B1

## CPC

- B01D 67/00931: {by introduction of specific groups after membrane formation, e.g. by grafting}
- B01D 67/0048: {by sol-gel transition}
- B01D 69/108: {Inorganic support material}
- B01D 71/0213: {Silicon}
- B01D 71/0215: {Silicon carbide; Silicon nitride; Silicon oxycarbide}
- B01D 71/024: {Oxides}
- C04B 41/52: Multiple coating or impregnating {multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation}
- B01D 2323/38: Graft polymerization
- B01D 2325/02834: more than 0.1 and up to 1 µm
- B01D 2325/04: Characteristic thickness
- 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)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE

## Abstract

The invention concerns an inorganic filtering membrane characterized in that it comprises a support made of an inorganic material coated with at least a membrane separating layer consisting of metal hydroxide and/or oxide particles and at the surface of which organomineral and/or mineral units are covalently grafted. The invention also concerns a method for preparing said membranes and their use for filtering.

## Claims

### Claim 1

An inorganic filtration membrane comprising a support made of inorganic material coated with at least one separating membrane layer comprising particles of metal hydroxides and/or oxides, at the surface of which are covalently grafted organomineral units and/or mineral units derived from the treatment of said grafted organomineral units.

### Claim 2 (depends on 1)

An inorganic membrane according to claim 1, wherein the organomineral and/or mineral units are grafted at the surface of the separating membrane layer by covalent bonds established between the mineral functions of the organomineral and/or mineral units and those of the metal hydroxides and/or oxides in said separating membrane layer.

### Claim 3 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the grafted organomineral and/or mineral units are derived from hydrolysable organometallic complexes comprising at least one titanium and/or zirconium atom.

### Claim 4 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the grafted organomineral and/or mineral units are derived from hydrolysable organometallic complexes comprises organotitanates, organozirconates and/or organozircoaluminates.

### Claim 5 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the grafted organomineral and/or mineral units are derived from hydrolysable organometallic complexes with said organometallic complex comprising:
an organotitanate or organozirconate corresponding to either of formulae I and II below:
in which:
M represents a titanium or zirconium atom,
R represents a group
R1 and R2, which may be identical or different, represent a non-hydrolysable organic radical,
X represents a methylene or CO group,
m and n are equal to 0, 1, 2 or 3 and p is equal to 1 or 2 on condition that the sum of n, p and m is equal to 4 and with
when p is equal to 1,
Z1 and Z2, which may be identical or different, representing
—O—, —OC(O)—, —OC(O)O—, —OP(O)(O—)2, —OP(O)(OH)P(O)(O—)2, OP(O)(OH)P(O)(O—)3, OP(O)(O—)3, OS(O)2— or OS(O)2(—)3 and
when p is equal to 2,
Z1 and Z2 together forming a divalent chain of cyclic structure such as a cyclopyrophosphite; or is:
an organozircoaluminate corresponding to the general formula III below:
with R representing a (CH2)2, (CH2)4 or (CH2)12 hydrocarbon-based chain and X representing an NH2, SH, OH, COOH or
group.

### Claim 6 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the grafted organomineral and/or mineral units are derived from hydrolysable organometallic complexes with the organometallic complex being an organotitanate or organozirconate comprising:
isopropyl tri(N-ethylaminoethylamino)titanate,
necalkoxytri(N-ethylaminoethylamino)titanate,
neoalkoxytri(neodecanoyl)titanate,
isopropyl tri(isostearoyl)titanate,
isopropyl tri(dioctylphosphato)titanate,
trinecalkoxy(dioctylphosphato)titanate,
trineoalkoxy(neodecanoyl)zirconate,
trineoalkoxy(dodecanoyl)henzenesulphonyl-zirconate,
trineoalkoxy(ethylenediaminoethyl)zirconate, and/or
trinecalkoxy(m-aminophenyl)zirconate.

### Claim 7 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the mineral units grafted onto the surface are obtained by removing the organic functions present on grafted organomineral units.

### Claim 8 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the mineral units grafted onto the surface are Ti(OH)3, Ti(OH)2, Zr(OH)3 and/or Zr(OH)2, obtained by removing the organic functions present on grafted organomineral units.

### Claim 9 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the degree of grafting ranges between about 10 and about 80%.

### Claim 10 (depends on 1)

An inorganic filtration membrane according to claim 1, which contains various grafted organomineral units and/or various grafted mineral units.

### Claim 11 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the support is composed of carbon, glass, metal carbides, a metal, metal oxides or silicon carbide.

### Claim 12 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the support is a ceramic monolithic support with an average equivalent pore diameter Ds of between 1 and 20 μm and a porosity of greater than 30%.

### Claim 13 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the support is a ceramic monolithic support with an average equivalent pore diameter Ds of between 1 and 20 μm and a porosity of greater than 30% and is made of grains of alumina Al2O3 at least partially coated with grains of titanium oxide TiO2.

### Claim 14 (depends on 1)

An inorganic filtration membrane according to claim 1, wherein the separating membrane layer is made of titanium oxide, alumina and/or zirconia.

### Claim 15

An inorganic filtration membrane comprising a support made of inorganic material coated with at least one separating membrane layer comprising particles of metal hydroxides and/or oxides, comprising, at the surface of said separating membrane layer, a molecular layer comprising organomineral units grafted onto the surface of the said separating layer, said organomineral units corresponding to the general formula IV below:
(RO)pM[Z1R1]n[Z2R2]m IV
in which:
M represents a titanium or zirconium atom,
R represents a group
R1 and R2, which may be identical or different, represent a non-hydrolysable organic radical,
m and n are equal to 0, 1, 2 or 3 and p is equal to 1 or 2, on condition that the sum of n, p and m is equal to 4 and with
when p is equal to 1,
Z1 and Z2, which may be identical or different, representing
—O—, —OC(O)—, —OC(O)O—, —OP(O)(O—)2, —OP(O)(OH)P(O)(O—)2, OP(O)(OH)P(O)(O—)3, OP(O)(O—)3, OS(O)2— or OS(O)2(—)3 and
when p is equal to 2,
Z1 and Z2 together forming a divalent chain of cyclic structure such as a cyclopyrophosphite.

### Claim 16 (depends on 15)

An inorganic filtration membrane according to claim 15, wherein the grafted or organomineral units are groups comprising tri(N-ethyl-aminoethylamino)titanate, tri(neodecancyl)titanate, tri(isostearoyl)titanate and/or tris(dioctylphosphato)titanate derivatives.

### Claim 17 (depends on 1)

A method for nanofiltration, ultrafiltration or microfiltration, comprising contacting the inorganic filtration membrane according to claim 1 with a material to be filtered.

### Claim 18 (depends on 1)

A method for isolating and/or separating solutes present in a solution, comprising contacting the inorganic filtration membrane according to claim 1 with a solution containing solutes.

### Claim 19 (depends on 18)

The method according to claim 18, wherein the solutes are metal ions, chemical compounds and/or proteins.

### Claim 20 (depends on 1)

A process which is useful for preparing an inorganic filtration membrane which is modified by grafting with organomineral and/or mineral units as defined in claim 1, which comprises:
conditioning the separating membrane layer to be modified in the solvent of the grafting solution,
circulating the grafting solution, comprising at least one organomineral to be grafted, through the conditioned separating membrane layer, under operating conditions that are suitable for carrying out said grafting,
rinsing said grafted separating membrane layer, so as to remove the excess of unreacted organominerals, and
optionally, treating the grafted organomineral units in order to remove their organic functions, and
drying said grafted membrane.

### Claim 21 (depends on 20)

A process according to claim 20, wherein the organomineral to be grafted is a hydrolysable organometallic complex comprising at least one titanium or zirconium atom.

### Claim 22 (depends on 20)

A process according to claim 20, wherein the organomineral to be grafted is an organotitanate or organozirconate, corresponding to either of the general formulae I and II below:
in which:
M represents a titanium or zirconium atom,
R represents a group
R1 and R2, which may be identical or different, represent a non-hydrolysable organic radical,
X represents a methylene or CO group,
m and n are equal to 0, 1, 2 or 3 and p is equal to 1 or 2 on condition that the sum of n, p and m is equal to 4 and with
when p is equal to 1,
Z1 and Z2, which may be identical or different, representing
—O—, —OC(O)—, —OC(O)O—, —OP(O)(O—)2, —OP(O)(OH)P(O)(O—)2, OP(O)(OH)P(O)(O—)3, OP(O)(O—)3, OS(O)2— or OS(O)2(—)3 and
when p is equal to 2,
Z1 and Z2 together forming a divalent chain of cyclic structure; and/or comprising:
isopropyl tri(N-ethylaminoethylamino)titanate,
neoalkoxytri(N-ethylaminoethylamino)titanate,
neoalkoxytri(neodecanoyl)titanate,
isopropyl tri(isostearoyl)titanate,
isopropyl tri(dioctylphosphato)titanate,
trineoalkoxy(dioctylphosphato)titanate,
trineoalkoxy(neodecanoyl)zirconate,
trineoalkoxy(dodecanoyl)benzenesulphonyl-zirconate,
trineoalkoxy(ethylenediamincethyl)zirconate, and
trineoalkoxy(m-aminophenyl)zirconate.

### Claim 23 (depends on 20)

A process according to claim 20, wherein the grafting solvent is an alcoholic solvent.

### Claim 24 (depends on 20)

A process according to claim 20, wherein the grafting solvent is isopropanol.

### Claim 25 (depends on 20)

A process according to claim 20, wherein the grafting solution has a concentration of between about 5 and about 100 g/l of at least one organomineral.

### Claim 26 (depends on 20)

A process according to claim 20, wherein the concentration of the grafting solution is between about 20 and about 70 g/l of at least one organomineral.

### Claim 27 (depends on 20)

A process according to claim 20, wherein the inorganic membrane to be modified comprises a support composed of carbon, glass, metal carbides, a metal, metal oxides or silicon carbide.

### Claim 28 (depends on 20)

A process according to claim 20, wherein the inorganic membrane to be modified comprises a ceramic monolithic support with an average equivalent pore diameter Ds of between 1 and 20 μm and a porosity of greater than 30%.

### Claim 29 (depends on 20)

A process according to claim 20, wherein the inorganic membrane to be modified comprises a ceramic monolithic support with an average equivalent pore diameter Ds of between 1 and 20 μm and a porosity of greater than 30% and said ceramic being made of grains of alumina Al2O3 at least partially coated with grains of titanium oxide TiO2.

### Claim 30 (depends on 20)

A process according to claim 20, wherein the inorganic membrane to be modified comprises a separating membrane layer made of titanium oxide, alumina and/or zirconia.

### Claim 31 (depends on 20)

A process according to claim 20, wherein the conditioning of the membrane to be grafted is carried out in a closed circuit.

### Claim 32 (depends on 20)

A process according to claim 20, wherein the grafting operation is carried out in a closed circuit with recycling of the permeate and of the retentate.

### Claim 33 (depends on 20)

A process according to claim 20, wherein the said grafted membrane, freed of the excess organominerals by rinsing and not dried, undergoes an acidic or alkaline hydrolysis in oxidative medium to remove the organic functions present on the grafted organomineral units.

### Claim 34 (depends on 20)

A process according to claim 20, wherein the membranes grafted with mineral units, obtained after said process, are subjected to a new grafting operation.