Modification of polyvinylidene fluoride membrane and method of filtering
First Claim
1. A filter medium comprising a microporous polyvinylidene fluoride membrane having a polymer containing vinyltriphenyl phosphonium bromide and a member of the group consisting of an acrylate and a methacrylate grafted thereto in a concentration sufficient to provide a surface of said membrane with a positive charge such that there is a minimal susceptibility to the extraction of said polymer.
1 Assignment
0 Petitions
Accused Products
Abstract
There is provided a filter medium comprising a microporous polyvinylidene fluoride membrane and a polymer containing a positively charged organic phosphonium compound grafted to the membrane in a concentration sufficient to provide a surface of said membrane with a positive charge such that there is minimal susceptibility to the extraction of said polymer. The polymer may also contain an acrylate or methacrylate. There is also provided a method for ultrapurifying a liquid and an ultrapurifying system for water.
147 Citations
24 Claims
- 1. A filter medium comprising a microporous polyvinylidene fluoride membrane having a polymer containing vinyltriphenyl phosphonium bromide and a member of the group consisting of an acrylate and a methacrylate grafted thereto in a concentration sufficient to provide a surface of said membrane with a positive charge such that there is a minimal susceptibility to the extraction of said polymer.
-
9. A filter medium comprising a microporous polyvinylidene fluoride membrane and a polymer grafted thereto, said polymer grafted to said membrane from a solution comprising from about 1.0 weight % to about 2.0 weight % of vinyl triphenyl phosphonium bromide and from about 0.1 weight % to about 0.5 weight % of a hydroxylated acrylate or methacrylate, said weight % based on total weight of said grafting solution, and the remainder of said grafting solution being water.
- 10. A method for ultrapurifying a liquid having macromolecular contaminants therein comprising passing the liquid through a microporous polyvinylidene fluoride membrane having a polymer of vinyltriphenyl phosphonium bromide and a member of the group consisting of an acrylate and a methacrylate grafted thereto in a concentration sufficient to provide a surface of said membrane with a positive charge such that there is a minimal susceptibility to the extraction of the polymer.
-
16. An ultrapure water treatment system comprising:
-
a housing; a water supply including a water inlet and a water outlet communicating within said housing and defining a path of travel of the water from said inlet to said outlet; irradiation means for irradiating water in the housing with UV light of wavelength of about 180 nm to about 190 nm, and a filter medium positioned within said path of travel of the water, said filter medium comprising a microporous polyvinylidene fluoride membrane having a polymer containing vinyl triphenyl phosphonium bromide and a member of the group consisting of an acrylate and a methacrylate grafted thereto in a concentration sufficient to provide a surface of said membrane with a positive charge such that there is minimal susceptibility to the extraction of said polymer. - View Dependent Claims (17, 18, 19, 20, 21, 22)
-
-
23. An ultrapure water treatment system comprising:
-
a housing, a water supply including a water inlet and a water outlet communication with said housing and defining a path of travel of the water from said inlet to said outlet, irradiation means for irradiating water in the housing with UV light of wavelength of about 180 nm to about 190 nm, and a filter medium positioned within said path of travel of the water, and between said housing and said water outlet or said water inlet or both, said filter medium comprising a microporous polyvinylidene fluoride membrane and a polymer, said polymer being grafted to said membrane from a solution containing from about 1 weight % to 2.0 weight % of a positively charged vinyl triphenyl phosphonium bromide and from about 0.1 weight % to about 0.5 weight % of a hydroxylated acrylate or methacrylate, said weight % based on the total weight of said solution, and the remainder of said solution being water. - View Dependent Claims (24)
-
Specification