Flux enhancing agent for improving composite polyamide reverse osmosis membrane performance
View Patent ↗The present disclosure describes an additive that may be used in the manufacture of thin-film polyamide composite membranes. Thin-film polyamide composite membranes are used in filtration processes, such as reverse osmosis and nanofiltration. The additive may be an amino-siloxane compound. The amino-siloxane compound includes repeated groups of silicon bonded to oxygen with at least one amine functional group. Optionally, the amino-siloxane compound may also include a hydrophilic group. The additive reacts with an aqueous phase and an organic phase to form a thin polyamide film on a porous substrate.
1. A composite membrane for reverse osmosis or nanofiltration, the membrane comprising:
a porous substrate;
a polymer layer on a surface of the porous substrate, wherein the polymer layer comprises a reaction product of (i) a polyacyl halide that is soluble in an organic phase, (ii) an amine that is soluble in an aqueous phase, and (iii) an amino-siloxane compound wherein the amino siloxane compound is different from the amine and is a compound selected from the group consisting of:
(I) a compound of the formula
wherein R1 and R2 may be the same or different, and are C1-C20 alkyl or alkoxy groups; R3 may be a C1-C4 alkyl group, or H; Q is either —(CH 2 ) 3 — or —CH 2 CH(CH 3 )CH 2 —; X is either —CH 2 CH(OH)CH 2 OH or H; a, b, c, d, e are integers such that the sum of a+b+c+d+e is less than 100, if b is 0, then d or e must be greater than 0, if d is 0, then b or e must be greater than 0; and if e is 0, then b or d must be greater than 0; and, y1, y2, z1, z2 are each integers between 0 to 10;
(II) a compound of the formula
wherein R is CH 3 to C 15 H 31 ; X is 75% of —CH 2 CH(OH)CH 2 OH and 25% H; and n is an integer between 1 and 100;
(III) a compound of the formula
wherein x is either —CH 2 CH(OH)CH 2 OH or H; and n is an integer between 4 and 100;
(IV) a compound of the formula
wherein a and b are integers between 1 and 100 and the sum of a+b is not greater than 100;
(V) a compound of the formula
wherein a, b and c are integers between 1 and 100, the sum of a+b+c is not greater than 100 and x is an integer between 1 and 50;
(VI) the compound according to formula
(VII) the compound according to formula
(VIII) the compound according to formula
(IX) the compound according to formula
(X) the compound according to formula
(XI) the compound according to formula
(XII) the compound according to formula
(XIII) the compound according to formula
(XIV) the compound according to formula
(XV) the compound according to formula
(XVI) the compound according to formula
and
(XVII) the compound according to formula
2. The composite membrane of claim 1 wherein the amino-siloxane compound is a compound of the formula:
wherein R1 and R2 may be the same or different, and are C1-C20 alkyl or alkoxy groups; R3 may be a C1-C4 alkyl group, or H; Q is either —(CH 2 ) 3 — or —CH 2 CH(CH 3 )CH 2 —; X is either-CH 2 CH(OH)CH 2 OH or H; a, b, c, d, e are integers such that the sum of a+b+c+d+e is less than 100, if b is 0, then d or e must be greater than 0, if d is 0, then b or e must be greater than 0; and if e is 0, then b or d must be greater than 0; and, y1, y2, z1, z2 are each integers between 0 to 10.
3. The composite membrane of claim 1 wherein the amino-siloxane compound is a compound of the formula:
wherein R is CH 3 to C 15 H 31 ; X is 75% of —CH 2 CH(OH)CH 2 OH and 25% H; and n is an integer between 1 and 100.
4. The composite membrane of claim 1 wherein the amino-siloxane compound is a compound of the formula:
wherein x is either —CH 2 CH(OH)CH 2 OH or H; and n is an integer between 4 and 100.
5. The composite membrane of claim 1 wherein the amino-siloxane compound is a compound selected from the group consisting of:
wherein a and b are integers between 1 and 100 and the sum of a+b is not greater than 100;
wherein a, b and c are integers between 1 and 100, the sum of a+b+c is not greater than 100 and x is an integer between 1 and 50;
6. The composite membrane of claim 1 wherein the polyacyl halide is trimesoyl chloride.