Hydrophilic-oleophobic copolymer composition and uses thereof
View Patent ↗Provided herein are copolymers and copolymer compositions that are both hydrophilic and oleophobic. The copolymers include structural units derived from a fluoroalkyl monomer and a zwitterionic monomer. It further relates to membranes formed by coating a porous substrate with the copolymeric compositions. The copolymeric coating imparts hydrophilicity and oleophobicity/oil-tolerance to the membranes. The uses of such membranes as microfiltration membrane or ultrafiltration membrane are also provided.
1. A method of treating a contaminated water comprising:
providing the contaminated water comprising water and oil;
providing a membrane comprising a porous substrate and a coating attached to the porous substrate, wherein at least one of the porous substrate or the coating comprises a copolymer comprising 1 to 10 mole % of a structural unit of formula I; and 90 to 99 mole % of a structural unit of formula II,
wherein
R 1 is a linear or branched C 1 -C 30 fluoroalkyl group;
R 2 and R 3 are independently at each occurrence a hydrogen, or a linear or branched C 1 -C 4 alkyl group;
either R 4 and R 5 are independently at each occurrence a linear or branched C 1 -C 12 alkyl group, a C 5 -C 12 carbocyclic group, or a C 5 -C 12 heterocyclic group, and R 6 and R 7 are independently at each occurrence a linear or branched C 1 -C 12 alkylene group, a linear or branched C 2 -C 12 alkenylene group, a linear or branched C 2 -C 12 alkynlene group, a C 5 -C 12 carbocyclic group, or a C 5 -C 12 heterocyclic group, or at least two of R 4 , R 5 , R 6 , or R 7 together with the nitrogen atom to which they are attached form a heterocyclic ring containing 5 to 7 atoms;
X is independently at each occurrence an —O— or —NH—;
Y is a sulfite group or a carboxylate group; and
m and n are independently at each occurrence an integer ranging from 1 to 5; and
passing the contaminated water through the membrane to generate a treated water.
2. The method of claim 1 , wherein the contaminated water is a produced water.
3. The method of claim 1 , wherein the contaminated water comprises total organic components in a range between 1 and 1000 ppm.
4. The method of claim 3 , wherein the contaminated water comprises free un-dissolved oil in a range between 1 and 500 ppm, total dissolved solids in a range between 5000 and 200000 ppm, and total suspended solids in a range between 1 and 2000 ppm.
5. The method of claim 4 , wherein the concentration of the suspended solids in the treated water is lower than that of the contaminated water.
6. The method of claim 1 , wherein the copolymer comprises 1 to 10 mole % of a structural unit of formula VII, and 90 to 99 mole % of a structural unit of formula VIII, wherein R 1 is a linear C 5 -C 8 fluoroalkyl group; and
7. The method of claim 6 , wherein the porous substrate has a pore size ranging from about 0.01 micron to about 50 micron.
8. The method of claim 6 , wherein the porous substrate comprises a polymer selected from the group consisting of polytetrafluoroethylene, expanded polytetrafluoroethylene, polysulfone, polyethersulfone, polypropylene, polyvinylidine fluoride, polyamide, polystyrene, polyethylene, polyacrylonitrile, cellulose-based materials and combinations thereof.
9. The method of claim 6 , wherein the porous substrate is expanded polytetrafluoroethylene.
10. The method of claim 6 , wherein the copolymer comprises 10 mole % of the structural unit of formula VII, and 90 mole % of the structural unit of formula VIII.
11. The method of claim 10 , wherein R 1 of the copolymer is —C 6 F 13 .