John Ahren Cadotte, Age 4715118 W Scott Rd, Lco Commercial Cent, WI 54843

4765897, Aug 23, 1988

Apr 28, 1986

6/856519

John E. Cadotte - Minnetonka MN
David R. Walker - Kilmarnock, GB6

The Dow Chemical Company - Midland MI

B01D 1300
B32B 2734

21050023

A novel water softening membrane and process for making the same is described. The membrane can be prepared by treating a polyamide reverse osmosis membrane with a strong mineral acid followed by treatment with a rejection enhancing agent. The resulting membrane at transmembrane pressures of 50 psi can attain a magnesium sulfate rejection with a 0. 2 percent aqueous solution of more than 90 percent with a water flux of more than 15 gallons per square foot per day.

4812238, Mar 14, 1989

Aug 10, 1987

7/083134

John E. Cadotte - Minnetonka MN
Donald L. Schmidt - Midland MI

The Dow Chemical Company - Midland MI
Filmtec Corp. - Minneapolis MN

B01D 1300

210636

An improved reverse osmosis membrane and process for making the same is described. The membrane is prepared by treating a polymer bearing primary amine groups with nitrous acid or a diazonium compound so as to react the resulting diazonium groups with other groups present. The resulting membrane possesses improved chlorine resistance. When the nitrous acid treatment is employed, the water flux of a polyamide membrane is frequently increased with little or no effect on the salt rejection of the membrane.

4259183, Mar 31, 1981

Jan 10, 1979

6/002396

John E. Cadotte - Minnetonka MN

Midwest Research Institute - Kansas City MO

B01D 1300
C08G 6942
C08C 1920

210654

A composite permselective membrane is prepared by reaction of a film or layer containing cycloaliphatic polyfunctional secondary amines with a triacyl halide or its mixture with a diacyl halide. The membrane is useful in separating components of fluid mixtures or solutions, such as the removal of salts from aqueous solutions by reverse osmosis.

5658460, Aug 19, 1997

May 7, 1996

8/646411

John E. Cadotte - Minnetonka MN
Daniel A. Batzel - Glenview IL
Thomas F. Stocker - San Diego CA

The Dow Chemical Company - Midland MI

B01D 3900

21050038

To prevent the deterioration of the flux and salt rejection characteristics of polyamide, thin-film, composite reverse osmosis membranes when subjected to relatively high temperature drying conditions, an unsubstituted inorganic ammonium cation salt of an acid is incorporated into the process of manufacture. The ammonium salt can be introduced into the process either before or after the membrane is formed by interfacial polymerization so long as it is added before the membrane is heated.

4824574, Apr 25, 1989

Jun 13, 1988

7/205523

John E. Cadotte - Minnetonka MN
David R. Walker - Kilmarnock, GB6

The Dow Chemical Company - Midland MI

C02F 144

210654

A novel water softening membrane and process for making the same is described. The membrane can be prepared by treating a polyamide reverse osmosis membrane with a strong mineral acid followed by treatment with a rejection enhancing agent. The resulting membrane at transmembrane pressures of 50 psi can attain a magnesium sulfate rejection with a 0. 2 percent aqueous solution of more than 90 percent with a water flux of more than 15 gallons per square foot per day.

4834886, May 30, 1989

Jan 8, 1987

7/001488

John E. Cadotte - Minnetonka MN

Filmtec Corporation - Minneapolis MN

B01D 1300
B05D 500

210490

A novel hyperfiltration membrane and process for making the same is described. The membrane is useful for processing copper electroless solutions to concentrate for re-use salts of chelating agents. The membrane can be prepared by crosslinking a water-compatible polymer in the presence of a phosphorus-containing acid, such as phosphoric acid, wherein the acid is present in a sufficient amount to catalyze crosslinking and to form a plurality of pores in the coating when dried.

4888116, Dec 19, 1989

Dec 19, 1988

7/286677

John E. Cadotte - Minnetonka MN
Donald L. Schmidt - Midland MI

The Dow Chemical Company - Midland MI
Filmtec Corp. - Minneapolis MN

B01D 1300
C02F 144

210636

A method of improving the properties of a reverse osmosis membrane having a polyamide discriminating layer containing residual aromatic primary amine groups is described. In this method, the polyamide discriminating layer of the membrane is treated with an aqueous solution of a reagent which reacts with primary amine groups to form diazonium salt groups or derivatives of diazonium salt groups. This method results in a membrane possessing improved chlorine resistance. When nitrous acid is employed as the reagent in the treatment, the water flux of the polyamide membrane is frequently increased with little or no effect on the salt rejection of the membrane.

4964998, Oct 23, 1990

Dec 13, 1989

7/450706

John E. Cadotte - Minnetonka MN
Robert J. Petersen - Minneapolis MN

FilmTec Corporation - Minneapolis MN

B01D 6102

210654

A method of separating water of reduced concentration of a selected solute via reverse osmosis, wherein the selected solute is sulfuric acid, sodium hydroxide, isopropanol, sodium nitrate or another solute having a much higher solute passage than sodium chloride. The reverse osmosis membrane is prepared by treating a crosslinked, polyamide discriminating layer with an amine-reactive reagent or compatible oxidant at conditions whereby the passage of the selected solute at a selected transmembrane pressure is reduced by at least 30 percent.