# US 2016/0355415 A1 · Chemical additives for enhancement of water flux of a membrane

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- Number: US 2016/0355415 A1
- Document ID: US20160355415A1
- Status: Published application
- Kind: A1
- Application number: 14/730,131
- Filed: 2015-06-03
- Published: 2016-12-08
- Earliest claimed: 2015-06-03
- Assignees: LG Nanoh20, Inc.
- Applicants: LG Nanoh20, Inc.
- Inventors: Jeff KOEHLER; Alexis FOSTER; Keunwon SONG; Young Ju LEE; Chongkyu SHIN
- Web page: https://patentgrep.com/patent/US20160355415A1

## CPC

- C02F 1/441: {by reverse osmosis}
- B01D 63/10: Spiral-wound membrane modules
- B01D 69/1251: {by interfacial polymerisation}
- B01D 69/1411: {containing dispersed material in a continuous matrix}
- B01D 69/148: {Organic/inorganic mixed matrix membranes}
- B01D 71/56: Polyamides, e.g. polyester-amides
- B01D 61/025: {Reverse osmosis; Hyperfiltration}
- B01D 2323/2189: Metal-organic compounds or complexes
- C02F 2103/08: Seawater, e.g. for desalination
- Y02A 20/131: Reverse-osmosis
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- 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)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

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 at low energy conditions. The process includes contacting a porous support membrane with an aqueous phase containing a polyamine and a flux enhancing combination of additives that includes a metal chelate additive containing a bidentate ligand and a metal atom or metal ion and a phosphoramide 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.

## Claims

### Claim 1

A process for preparing a thin film composite membrane, comprising:
(a) preparing an aqueous phase comprising a polyamine and an organic phase comprising a polyfunctional acid halide, wherein the aqueous phase or organic phase or both further include a flux enhancing combination that comprises:
(i) a metal chelate additive containing a bidentate ligand and a metal atom or metal ion; and
(ii) a phosphoramide;
(b) applying the aqueous phase to a surface of a porous support membrane to form a coated support membrane; and
(c) applying the organic phase to the coated support membrane and interfacially polymerizing the polyamine and the polyfunctional acid halide to form a discrimination layer of a thin film composite membrane comprising the porous support membrane and the discrimination layer, the thin film composite membrane having a water flux and that is greater than the water flux of a thin film composite membrane prepared in the absence of the flux enhancing combination.

### Claim 2 (depends on 1)

The process of claim 1, wherein the bidentate ligand is selected from among:
wherein each of R1, R2, R3, R4 and R5 separately is selected from among a C1-C10 alkyl, a halogenated C1-C10 alkyl, a 5-membered aromatic ring, a 6-membered aromatic ring, an aromatic bicyclic ring system containing two fused 6-membered rings, and an aromatic bicyclic ring system containing a 5-membered ring fused to a 6-membered aromatic ring.

### Claim 3 (depends on 2)

The process of claim 2, wherein the bidentate ligand is an acetylacetonate (acac) or fluorinated acetylacetonate.

### Claim 4 (depends on 1)

The process of claim 1, wherein the metal chelate additive containing a bidentate ligand and a metal atom or metal ion is selected from among Al(acac)3, Al(F6acac)3, Ba(acac)2, Ba(F6acac)2, Be(acac)2, Be(F6acac)2, Ca(acac)2, Ca(F6acac)2, Cd(acac)2, Cd(F6acac)2, Ce(acac)3, Ce(F6acac)3, Cr(acac)3, Co(acac)3, Cu(acac)2, Cu(F6acac)2, Dy(acac)3, Er(acac)3, Fe(acac)2, Fe(acac)3, Ga(acac)3, Hf(acac)4, In(acac)3, K(acac), Li(acac), Mg(acac)2, Mg(F6acac)2, Mn(acac)2, Mn(acac)3, MoO2(acac)2, MoO2(F6acac)2, Na(acac), Nd(acac)3, Nd(F6acac)3, Ni(acac)2, Ni(F6acac)2, Pd(acac)2, Pr(acac)3, Pr(F6acac)3, Ru(acac)3, Ru(F6acac)3, Sc(acac)2, Sc(F6acac)2, Sm(acac)3, Sn(acac)2, Sn(acac)2Cl2, t-butyl-Sn(acac)2, t-butyl-Sn(acac)2Cl2, Sn(F6acac)2, Sr(acac)2, Sr(F6acac)2, Tb(acac)3, V(acac)3, Y(acac)3, Y(F6acac)3, Zn(acac)2, Zn(F6acac)2, and Zr(acac)4, wherein F6acac refers to 1,1,1,5,5,5-hexafluoroacetylacetonate.

### Claim 5 (depends on 1)

The process of claim 1, wherein the bidentate ligand is a beta-diketonate or a fluorinated beta-diketonate.

### Claim 6 (depends on 5)

The process of claim 5, wherein the bidentate ligand is selected from among pentane-2,4-dionate, 1,5-difluoropentane-2,4-dionate, 1,1,5,5-tetrafluoropentane-2,4-dionate, 1,1,1,5,5,5-hexafluoropentane-2,4-dionate, propane-1,3-dionate, butane-1,3-dionate, 4-fluorobutane-1,3-dionate, 4,4-difluorobutane-1,3-dionate, 4,4,4-trifluorobutane-1,3-dionate, heptane-3,5-dionate, 1-fluorohexane-2,4-dionate, 1,5-difluoropentane-2,4-dionate, 1,1,5-trifluoropentane-2,4-dionate, 1,1,5,5-tetrafluoropentane-2,4-dionate, 1,1,1,5,5-pentafluoropentane-2,4-dionate, 1,1,1,5,5,5-hexafluoropentane-2,4-dionate and octane-3,5-dionate and combinations thereof.

### Claim 7 (depends on 1)

The process of claim 1, wherein the amount of bidentate ligand in the metal chelate additive yields a concentration of bidentate ligand in the aqueous phase of step (a) of from about 0.001 wt % to about 1 wt %, based on the weight of the aqueous phase.

### Claim 8 (depends on 1)

The process of claim 1, wherein the metal atom or metal ion is selected from Group 2 or Group 13 of the periodic table.

### Claim 9 (depends on 8)

The process of claim 8, wherein the metal atom or metal ion is an alkaline earth metal.

### Claim 10 (depends on 1)

The process of claim 1, wherein the amount of metal atom or metal ion in the metal chelate additive yields a concentration of metal atom or metal ion in the aqueous phase or the organic phase of step (a) of from about 0.00001 wt % to about 1 wt %, based on the weight of the aqueous phase or the organic phase.

### Claim 11 (depends on 1)

The process of claim 1, wherein the amount of metal chelate additive added to the aqueous phase or organic phase yields a concentration of metal chelate additive in the aqueous phase or the organic phase of step (a) of from about 0.001 wt % to about 1 wt %, based on the weight of the aqueous phase or the organic phase.

### Claim 12 (depends on 1)

The process of claim 1, wherein the phosphoramide is of the formula:
wherein each of R6, R7, R8, R9, R10 and R11 separately is selected from among hydrogen, a C1-C10 alkyl, a halogenated C1-C10 alkyl, a 5-membered aromatic ring, a 6-membered aromatic ring, an aromatic bicyclic ring system containing two fused 6-membered rings, and an aromatic bicyclic ring system containing a 5-membered ring fused to a 6-membered aromatic ring.

### Claim 13 (depends on 1)

The process of claim 1, wherein the amount of phosphoramide present in the combination yields a concentration of phosphoramide in the aqueous phase or organic phase of step (a) of from about 0.1% to 4% based on the weight of the aqueous phase or organic phase.

### Claim 14 (depends on 1)

The process of claim 1, wherein the phosphoramide is hexamethylphosphoramide (HMPA).

### Claim 15 (depends on 1)

The process of claim 1, further comprising adding a processing aid selected from among a surfactant, a co-solvent, a drying agent, a catalyst, or any combination thereof to the aqueous phase prior to applying the aqueous phase to the porous support membrane.

### Claim 16 (depends on 15)

The process of claim 15, wherein the amount of processing aid in the aqueous phase prior to applying the aqueous phase to the porous support membrane is from about 0.001 wt % to about 10 wt % based on the weight of the aqueous phase.

### Claim 17 (depends on 1)

The process of claim 1, wherein the aqueous phase or the organic phase or both further comprises nanoparticles selected from among zeolites, fullerenes and carbon nanotubes and combinations thereof.

### Claim 18 (depends on 17)

The process of claim 17, wherein:
a) the nanoparticles are present in the aqueous phase of step (a) in an amount from about 0.001 wt % to about 0.5 wt % based on the weight of the aqueous phase; or
b) the nanoparticles are present in the organic phase of step (b) in an amount from about 0.001 wt % to about 0.5 wt % based on the weight of the organic phase; or
c) both a) and b).

### Claim 19 (depends on 1)

The process of claim 1, wherein the thin film composite membrane is a reverse osmosis membrane.

### Claim 20 (depends on 1)

A thin film composite membrane prepared according to the process of claim 1.

### Claim 21 (depends on 20)

The thin film composite membrane of claim 20 that is a reverse osmosis membrane.

### Claim 22 (depends on 21)

The reverse osmosis membrane of claim 21, wherein:
the membrane exhibits a water flux of at least 20 gfd when the membrane is exposed to deionized water containing 2,000 ppm NaCl at a temperature of 25° C. and a pressure of 150 psi; or
the membrane exhibits a salt rejection of at least 99.3%, when the membrane is exposed to deionized water containing 2,000 ppm NaCl at a temperature of 25° C. and a pressure of 150 psi.

### Claim 23 (depends on 19)

A method of purifying tap water or seawater or brackish water containing 2,000 ppm or less NaCl, comprising:
a) contacting the tap water with the reverse osmosis membrane of claim 19 at a hydrostatic pressure of about 150 psi or less; or
b) contacting the seawater with the reverse osmosis membrane of claim 19 at a hydrostatic pressure of about 800 psi or less; or
c) contacting the brackish water with the reverse osmosis membrane of claim 19 at a hydrostatic pressure of about 225 psi or less or about 150 psi or less.

### Claim 24 (depends on 23)

The method of claim 23, wherein:
contacting the membrane with seawater produces a water flux of at least 40 gfd at 800 psi; or
contacting the membrane with brackish water produces a water flux of at least 20 gfd at 150 psi.

### Claim 25 (depends on 21)

A reverse osmosis module, comprising the reverse osmosis membrane of claim 21 spirally wound around a central perforated tube.

### Claim 26

A reverse osmosis membrane, comprising:
a support membrane; and
on a surface of the support membrane a discrimination layer formed by interfacially polymerizing a polyamine and a polyfunctional acid halide, wherein:
the membrane exhibits a water flux of at least 20 gfd when the membrane is exposed to deionized water containing 2,000 ppm NaCl at a temperature of 25° C. and a pressure of 150 psi; or
the membrane exhibits a salt rejection of at least 99.3% when the membrane is exposed to deionized water containing 2,000 ppm NaCl at a temperature of 25° C. and a pressure of 150 psi.