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Metal recovery
Patents
Transparent membrane cell cultivation device. by Millipore open end
tubular container
closed end
polymer. an amine-substituted crown ether derivative is reacted with a selected prepolymer to produce the polymeric crown ether. Prepolmers can be polymeric acid chlorides. e.g. acryloyl chloride. and/or polymeric cyclic anhydrides. e.g. maleic anhydride. A preferred embodiment of the invention refers to a membrane formed from acryloyl chloride and an 18crown-6 derivative. together with a polyaramide support polymer. Numerous examples are given. Patent number: US 4906376 Date: 6 March 1990 Inventor: 'I' Fyles Applicant: University of Victoria.
Be
protrusions
Patent number: l:S 490HZ:J6 Date: 13 March 19~10 Inventors: t\ M Pitt. M J Steuck Applicant: Millipore Corp
Metal recovery In metal recoverv, membrane based ion exchange and separation systems can be used instead of conventional solvent extraction or ion exhange units. for continuous removal of the desired metal ion from solutions through the membrane. Suitable membrane svsterns based on mobile carriers have been investigated for recoverv of metals ranging from alkali and alkaline earth cations to coppt!r. chromium and uranium. The invention is for a functional membrane providing proton-driven ion transport. A two component membrane is described. the first component being an active polymer possessing active cation-binding
12
sites and the second component being a polymer support. The active polymer can be formed from a crown ether. a cryptand or an acvclic complexone with an ionisable acidic site. such as carboxylic. sulphonic or phenol, incorporated into a polymer backbone via a spacer component. The polymer support can be a polyararnide, a polysulphone. or a polypiperazine-fumaramide. An object of the invention is to provide proton-cation countertransport. which can be used to "pump" cations against their concentration gradients. using pH gradient to drive the process. Membranes would thus provide cation binding sites and ionisable groups. The binding site can be a crown ether
o II
ro~
-~(:r 0
0)
II
0
o
~o~
0
and the ionisable group can be carboxvlic acid. To synthesise the active
Deionizing aqueous solutions Ion exchange devices and processes have been in existence a long time and most involve the use of ion exchange resins in packed columns. Ion exchange in aqueous media can also be effected using membranes. such as in electrodialysis (where electrical potential is used as the driving force to move the ions across the membane) and Donnan-Exchange (where the driving force is chemical potential). The patent specifies a process for deionizing aqueous solutions by circulating the ion-containing solution through a device in which an acid solution is passed through an assembly of cation exchange membranes and an alkali solution is passed through an assembly of anion exchange membranes. In a shell-and tube device. the aqueous solution is deionized while circulating on the shell side. while the acid and alkali solutions are passed through the tubes. Ion exchange takes place
Membrane Technology
Transparent membrane cell cultivation device. by Millipore open end
tubular container
closed end
polymer. an amine-substituted crown ether derivative is reacted with a selected prepolymer to produce the polymeric crown ether. Prepolmers can be polymeric acid chlorides. e.g. acryloyl chloride. and/or polymeric cyclic anhydrides. e.g. maleic anhydride. A preferred embodiment of the invention refers to a membrane formed from acryloyl chloride and an 18crown-6 derivative. together with a polyaramide support polymer. Numerous examples are given. Patent number: US 4906376 Date: 6 March 1990 Inventor: 'I' Fyles Applicant: University of Victoria.
Be
protrusions
Patent number: l:S 490HZ:J6 Date: 13 March 19~10 Inventors: t\ M Pitt. M J Steuck Applicant: Millipore Corp
Metal recovery In metal recoverv, membrane based ion exchange and separation systems can be used instead of conventional solvent extraction or ion exhange units. for continuous removal of the desired metal ion from solutions through the membrane. Suitable membrane svsterns based on mobile carriers have been investigated for recoverv of metals ranging from alkali and alkaline earth cations to coppt!r. chromium and uranium. The invention is for a functional membrane providing proton-driven ion transport. A two component membrane is described. the first component being an active polymer possessing active cation-binding
12
sites and the second component being a polymer support. The active polymer can be formed from a crown ether. a cryptand or an acvclic complexone with an ionisable acidic site. such as carboxylic. sulphonic or phenol, incorporated into a polymer backbone via a spacer component. The polymer support can be a polyararnide, a polysulphone. or a polypiperazine-fumaramide. An object of the invention is to provide proton-cation countertransport. which can be used to "pump" cations against their concentration gradients. using pH gradient to drive the process. Membranes would thus provide cation binding sites and ionisable groups. The binding site can be a crown ether
o II
ro~
-~(:r 0
0)
II
0
o
~o~
0
and the ionisable group can be carboxvlic acid. To synthesise the active
Deionizing aqueous solutions Ion exchange devices and processes have been in existence a long time and most involve the use of ion exchange resins in packed columns. Ion exchange in aqueous media can also be effected using membranes. such as in electrodialysis (where electrical potential is used as the driving force to move the ions across the membane) and Donnan-Exchange (where the driving force is chemical potential). The patent specifies a process for deionizing aqueous solutions by circulating the ion-containing solution through a device in which an acid solution is passed through an assembly of cation exchange membranes and an alkali solution is passed through an assembly of anion exchange membranes. In a shell-and tube device. the aqueous solution is deionized while circulating on the shell side. while the acid and alkali solutions are passed through the tubes. Ion exchange takes place
Membrane Technology