Organic Solvent Purifier And Method Of Using

Abstract

A purifier for removing metal, such as chromium, from an organic solvent is disclosed. The purifier comprises a housing having a fluid inlet and a fluid outlet in fluid communication with the fluid inlet; a volume of ion-exchange resin disposed within the housing downstream of the fluid inlet; and a filtration member downstream of the volume of ion-exchange resin, the filtration member comprising at least one microporous membrane having a substantially neutral surface and a microporous polytetrafluoroethylene membrane downstream of the at least one microporous membrane. A method for removing metal, including chromium, from an organic solvent using a purifier of the invention is also disclosed.

1 . A purifier for removing chromium from an organic solvent, comprising:
 a housing having a fluid inlet and a fluid outlet in fluid communication with the fluid inlet;   a volume of ion-exchange resin disposed within the housing downstream of the fluid inlet; and   a filtration member disposed downstream of the volume of ion-exchange resin, the filtration member comprising:
 at least one microporous polytetrafluoroethylene membrane having a substantially neutral surface modified with amide; and 
 a microporous polytetrafluoroethylene ion-exchange membrane downstream of the at least one amide-modified microporous polytetrafluoroethylene membrane, 
 wherein the at least one amide-modified microporous polytetrafluoroethylene membrane has a pore size rating greater than the pore size rating of the microporous polytetrafluoroethylene ion-exchange membrane and less than or equal to about 10 μm; and the microporous polytetrafluoroethylene ion-exchange membrane has a pore size rating by bubble point of about 1 nanometer to about 100 nanometers. 
   
     
     
         2 . A purifier for removing chromium from an organic solvent, comprising:
 a cylindrical housing having a longitudinal axis, a fluid inlet and a fluid outlet in fluid communication with the fluid inlet;   a volume of ion-exchange resin disposed within the cylindrical housing downstream of the fluid inlet, the ion-exchange resin being adapted to remove chromium species from the organic solvent; and   a pleated filtration member disposed concentrically around the longitudinal axis within the cylindrical housing and downstream of the volume of ion-exchange resin, the pleated filtration member comprising:
 at least one microporous polytetrafluoroethylene membrane having a substantially neutral surface modified with amide; and 
 a microporous polytetrafluoroethylene ion-exchange membrane downstream of the at least one amide-modified microporous polytetrafluoroethylene membrane, 
 wherein the at least one amide-modified microporous polytetrafluoroethylene membrane has a pore size rating greater than the pore size rating of the microporous polytetrafluoroethylene ion-exchange membrane and less than or equal to about 10 μm; and the microporous polytetrafluoroethylene ion-exchange membrane has a pore size rating by bubble point of about 1 nanometer to about 100 nanometers. 
   
     
     
         3 . (canceled) 
     
     
         4 . The purifier of  claim 1 , wherein a surface of the microporous polytetrafluoroethylene ion-exchange membrane is modified with sulfonic acid. 
     
     
         5 - 6 . (canceled) 
     
     
         7 . The purifier of  claim 1 , wherein the microporous polytetrafluorethylene membrane has a pore size rating of about 1 nanometer to about 50 nanometers. 
     
     
         8 . The purifier of  claim 7 , wherein the microporous polytetrafluorethylene membrane has a pore size rating of about 1 nanometer to about 25 nanometers. 
     
     
         9 . The purifier of  claim 1 , wherein the at least one microporous membrane having a substantially neutral surface and the microporous polytetrafluoroethylene membrane are bonded to one another in the filtration member. 
     
     
         10 . The purifier of  claim 1 , wherein the at least one microporous membrane having a substantially neutral surface and the microporous polytetrafluoroethylene membrane are disposed adjacent to one another in the filtration member. 
     
     
         11 . The purifier of  claim 1 , wherein the at least one microporous membrane having a substantially neutral surface and the microporous polytetrafluoroethylene membrane are each pleated. 
     
     
         12 . The purifier of  claim 1 , further comprising an ion-exchange resin vessel that contains the volume of ion-exchange resin. 
     
     
         13 . The purifier of  claim 12 , wherein the ion-exchange resin vessel comprises a net material or frit. 
     
     
         14 . The purifier of  claim 1 , further comprising a liquid distributor downstream of the volume of ion-exchange resin and upstream of the filtration member. 
     
     
         15 . The purifier of  claim 1 , wherein the organic solvent is an alcohol. 
     
     
         16 . The purifier of  claim 15 , wherein the alcohol is isopropanol. 
     
     
         17 . The purifier of  claim 1 , wherein the filtration member comprises at least three microporous membranes having a substantially neutral surface. 
     
     
         18 . A purifier for removing chromium from an organic solvent, comprising:
 a cylindrical housing having a longitudinal axis, a fluid inlet and a fluid outlet in fluid communication with the fluid inlet;   a volume of ion-exchange resin disposed within the cylindrical housing downstream of the fluid inlet, the ion-exchange resin being adapted to remove chromium species from the organic solvent; and   a pleated filtration member disposed concentrically around the longitudinal axis within the cylindrical housing and downstream of the volume of ion-exchange resin, the pleated filtration member comprising:
 at least three microporous membranes, each having a substantially neutral surface; and 
 a microporous polytetrafluoroethylene ion-exchange membrane downstream of the at least three microporous membranes, 
 wherein each microporous membrane is a microporous polytetrafluoroethylene membrane modified with amide and has a pore size rating greater than the pore size rating of the microporous polytetrafluoroethylene ion-exchange membrane and less than or equal to about 10 μm; and the microporous polytetrafluoroethylene ion-exchange membrane has a surface modified with sulfonic acid and a pore size rating of about 1 nanometer to about 25 nanometers. 
   
     
     
         19 . (canceled) 
     
     
         20 . A method for removing metal from an organic solvent, the method comprising passing a flow of the organic solvent through a purifier of  claim 1 . 
     
     
         21 - 22 . (canceled) 
     
     
         23 . The purifier of  claim 2 , wherein a surface of the microporous polytetrafluoroethylene ion-exchange membrane is modified with sulfonic acid. 
     
     
         24 . The purifier of  claim 2 , wherein the microporous polytetrafluorethylene membrane has a pore size rating of about 1 nanometer to about 50 nanometers. 
     
     
         25 . The purifier of  claim 24 , wherein the microporous polytetrafluorethylene membrane has a pore size rating of about 1 nanometer to about 25 nanometers. 
     
     
         26 . The purifier of  claim 2 , wherein the at least one microporous membrane having a substantially neutral surface and the microporous polytetrafluoroethylene membrane are bonded to one another in the filtration member. 
     
     
         27 . The purifier of  claim 2 , wherein the at least one microporous membrane having a substantially neutral surface and the microporous polytetrafluoroethylene membrane are disposed adjacent to one another in the filtration member. 
     
     
         28 . The purifier of  claim 2 , wherein the at least one microporous membrane having a substantially neutral surface and the microporous polytetrafluoroethylene membrane are each pleated. 
     
     
         29 . The purifier of  claim 2 , further comprising an ion-exchange resin vessel that contains the volume of ion-exchange resin. 
     
     
         30 . The purifier of  claim 29 , wherein the ion-exchange resin vessel comprises a net material or frit. 
     
     
         31 . The purifier of  claim 2 , further comprising a liquid distributor downstream of the volume of ion-exchange resin and upstream of the filtration member. 
     
     
         32 . The purifier of  claim 2 , wherein the organic solvent is an alcohol. 
     
     
         33 . The purifier of  claim 32 , wherein the alcohol is isopropanol. 
     
     
         34 . The purifier of  claim 2 , wherein the filtration member comprises at least three microporous membranes having a substantially neutral surface.