Patents by Inventor Subhas K. Sikdar

Subhas K. Sikdar has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 10245558
    Abstract: A nanocomposite membrane includes a macroporous polymer membrane having a plurality of pores. A plurality of metal nanoparticles are synthesized and immobilized within those plurality of pores. The nanoparticles are reduced and capped with a green reducing and capping agent such as green tea extract.
    Type: Grant
    Filed: June 15, 2016
    Date of Patent: April 2, 2019
    Assignees: THE UNIVERSITY OF KENTUCKY RESEARCH FOUNDATION, U.S. ENVIRONMENTAL PROTECTION AGENCY
    Inventors: Dibakar Bhattacharyya, Vasile Smuleac, Rajender S. Varma, Subhas K. Sikdar
  • Publication number: 20160367945
    Abstract: A nanocomposite membrane includes a macroporous polymer membrane having a plurality of pores. A plurality of metal nanoparticles are synthesized and immobilized within those plurality of pores. The nanoparticles are reduced and capped with a green reducing and capping agent such as green tea extract.
    Type: Application
    Filed: June 15, 2016
    Publication date: December 22, 2016
    Inventors: Dibakar Bhattacharyya, Vasile Smuleac, Rajender S. Varma, Subhas K. Sikdar
  • Patent number: 9375684
    Abstract: A nanocomposite membrane includes a macroporous polymer membrane having a plurality of pores. A plurality of metal nanoparticles are synthesized and immobilized within those plurality of pores. The nanoparticles are reduced and capped with a green reducing and capping agent such as green tea extract.
    Type: Grant
    Filed: April 30, 2012
    Date of Patent: June 28, 2016
    Assignee: THE UNIVERSITY OF KENTUCKY RESEARCH FOUNDATION
    Inventors: Dibakar Bhattacharyya, Vasile Smuleac, Rajender S. Varma, Subhas K. Sikdar
  • Patent number: 8518263
    Abstract: Hydrophobic, asymmetric membranes are formed integrally from elastomeric polymers. The membranes have a dense, discriminating layer and a thick, porous support layer and require no other support. The membranes of the invention provide an economic advantage over prior art composite membranes used for separating target organics from a mixture. Using the methods of the invention it is possible to separate two or more organic components wherein discrimination is made on the basis of molecular size.
    Type: Grant
    Filed: December 13, 2011
    Date of Patent: August 27, 2013
    Assignee: U.S. Environmental Protection Agency
    Inventors: Subhas K. Sikdar, John O. Burckle, Binay K. Dutta, Alberto Figoli, Enrico Drioli
  • Publication number: 20130062279
    Abstract: A nanocomposite membrane includes a macroporous polymer membrane having a plurality of pores. A plurality of metal nanoparticles are synthesized and immobilized within those plurality of pores. The nanoparticles are reduced and capped with a green reducing and capping agent such as green tea extract.
    Type: Application
    Filed: April 30, 2012
    Publication date: March 14, 2013
    Applicant: THE UNIVERSITY OF KENTUCKY RESEARCH FOUNDATION
    Inventors: Dibakar Bhattacharyya, Vasile Smuleac, Rajender S. Varma, Subhas K. Sikdar
  • Publication number: 20120132590
    Abstract: Hydrophobic, asymmetric membranes are formed integrally from elastomeric polymers. The membranes have a dense, discriminating layer and a thick, porous support layer and require not other support. The membranes of the invention provide an economic advantage over prior art composite membranes used for separating target organics from a mixture.
    Type: Application
    Filed: December 13, 2011
    Publication date: May 31, 2012
    Inventors: Subhas K. Sikdar, John O. Burckle, Binay K. Dutta, Alberto Figoli, Enrico Drioli
  • Patent number: 8096424
    Abstract: Using the methods of the invention, an elastomeric polymer is dissolved in a suitable solvent, cast in one of the membrane casting techniques using a phase inversion technique, and immersed in a coagulation bath comprised of suitable solvent/non-solvent pairs (e.g., THF/water and ethanol). Asymmetric membranes having a dense discriminating layer and a thicker porous support layer suitable for application in pervaporation processes were obtained in a single step. An increase of the polymer concentration in the casting solution gives a more dense layer. When cast as formed using the methods of the invention, the membrane obtained is an integrally skinned membrane comprising a thin, dense separation layer over a porous support layer (asymmetric membrane) formed in a single casting operation. The resulting membrane is homogenous with respect to chemical composition.
    Type: Grant
    Filed: November 14, 2006
    Date of Patent: January 17, 2012
    Assignee: The United States of America as represented by the Environmental Protection Agency
    Inventors: Subhas K. Sikdar, John O. Burckle, Binay K. Dutta, Alberto Figoli, Enrico Drioli
  • Publication number: 20080114087
    Abstract: Hydrophobic, asymmetric membranes are formed integrally from elastomeric polymers. The membranes have a dense, discriminating layer and a thick, porous support layer and require not other support. The membranes of the invention provide an economic advantage over prior art composite membranes used for separating target organics from a mixture.
    Type: Application
    Filed: November 14, 2006
    Publication date: May 15, 2008
    Inventors: Subhas K. Sikdar, John O. Burckle, Binay K. Dutta, Alberto Figoli, Enrico Drioli
  • Patent number: 6777374
    Abstract: Organic molecules are partially oxidized in that the gas phase on supported and immobilized photocatalysts deposited having a nanostructure. the photocatalysts are semiconductors such as titanium dioxide and are preferentially coated onto a substrate by flame aerosol coating.
    Type: Grant
    Filed: July 18, 2001
    Date of Patent: August 17, 2004
    Assignee: The United States of America as represented by the Environmental Protection Agency
    Inventors: Endalkachew Sahle-Demessie, Pratim Biswas, Michale A. Gonzalez, Zhong-Min Wang, Subhas K. Sikdar
  • Patent number: 6544419
    Abstract: A method for preparing a chemically activated or polyamino acid functionalized membrane includes the steps of permeating a silica-based membrane with a solution of silane and a solvent so as to react methoxy groups of the silane with silanol groups of the membrane to incorporate epoxide groups and attaching a polyamino acid to the membrane by reacting a terminal amine group of the polyamino acid with one of the epoxide groups on the membrane.
    Type: Grant
    Filed: August 20, 2001
    Date of Patent: April 8, 2003
    Assignee: University of Kentucky Research Foundation
    Inventors: Dibakar Bhattacharyya, Stephen M. Ritchie, Leonidas G. Bachas, Jamie A. Hestekin, Subhas K. Sikdar
  • Patent number: 6544418
    Abstract: A method for preparing and regenerating a chemically activated or polyamino acid functionalized membrane includes the steps of permeating the silica-based membrane with a solution of silane and a solvent so as to react methoxy groups of the silane with silanol groups of the membrane to incorporate epoxide groups and attaching a polyamino acid to the membrane by reacting a terminal amine group of the polyamino acid with one of the epoxide groups on the membrane. The membrane is regenerated after metal entrapment by utilizing helix-coil properties of polyamino acids.
    Type: Grant
    Filed: August 20, 2001
    Date of Patent: April 8, 2003
    Assignee: University of Kentucky Research Foundation
    Inventors: Dibakar Bhattacharyya, Stephen M. Ritchie, Leonidas G. Bachas, Jamie A. Hestekin, Subhas K. Sikdar
  • Publication number: 20020029955
    Abstract: Organic molecules are partially oxidized in that the gas phase on supported and immobilized photocatalysts deposited having a nanostructure. the photocatalysts are semiconductors such as titanium dioxide and are preferentially coated onto a substrate by flame aerosol coating.
    Type: Application
    Filed: July 18, 2001
    Publication date: March 14, 2002
    Inventors: Endalkachew Sahle-Demessie, Pratim Biswas, Michale A. Gonzalez, Zhong-Min Wang, Subhas K. Sikdar
  • Patent number: 6306301
    Abstract: An apparatus providing for metal ion/nitrate entrapment comprises a chemically activated, microfiltration, composite polymer and silica-based membrane including a polyamino acid attached thereto through reaction of a terminal amine group of the polyamino acid with the membrane. A method for preparing such a chemically activated or polyamino acid functionalized membrane includes the steps of permeating the silica-based membrane with a solution of silane and a solvent so as to react methoxy groups of the silane with silanol groups of the membrane to incorporate epoxide groups and attaching a polyamino acid to the membrane by reacting a terminal amine group of the polyamino acid with one of the epoxide groups on the membrane.
    Type: Grant
    Filed: December 3, 1999
    Date of Patent: October 23, 2001
    Assignee: University of Kentucky Research Foundation
    Inventors: Dibakar Bhattacharyya, Stephen M. Ritchie, Leonidas G. Bachas, Jamie A. Hestekin, Subhas K. Sikdar
  • Patent number: 6139742
    Abstract: A process is provided for making membrane-based sorbents with enhanced binding activity that are particularly useful for heavy metal sequestration. The process includes the step of selectively hydrolyzing a polyacetylated membrane in order to deacetylated a surface layer of said membrane including the pore surfaces and expose free hydroxyl groups. This is followed by the oxidizing of the hydroxyl groups to aldehyde groups. This is then followed by the attaching of a polycarboxylic acid such as a polyamino acid, polyalkenoic acid or polypeptide to the membrane through the aldehyde groups. Preferably, the hydrolyzing step is completed under alkaline conditions and the oxidizing step is completed using an aqueous solution of sodium periodate.
    Type: Grant
    Filed: May 26, 1998
    Date of Patent: October 31, 2000
    Assignee: University of Kentucky Research Foundation
    Inventors: Dibakar Bhattacharyya, Leonidas G. Bachas, Lawrence Cullen, Jamie A. Hestekin, Subhas K. Sikdar
  • Patent number: 6117328
    Abstract: Pervaporation membranes are used for removing volatile organic compounds from wastewaters. These pervaporation membranes are prepared by dispersing at least one hydrophobic adsorbent such as activated carbon uniformly into a polymer matrix.
    Type: Grant
    Filed: March 26, 1997
    Date of Patent: September 12, 2000
    Assignees: U.S. Environmental Protection Agency, University of Cincinnati
    Inventors: Subhas K. Sikdar, Wenchang Ji, Sun-tak Wang
  • Patent number: 6103121
    Abstract: A process is provided for making membrane-based sorbents with enhanced binding activity that are particularly useful for heavy metal sequestration. The process includes the step of selectively hydrolyzing a polyacetylated membrane in order to deacetylate a surface layer of said membrane and expose free hydroxyl groups. This is followed by the oxidizing of the hydroxyl groups to aldehyde groups. This is then followed by the attaching of a polycarboxylic acid such as a polyamino acid, polyalkenoic acid or polypeptide to the membrane through the aldehyde groups. Preferably, the hydrolyzing step is completed under alkaline conditions and the oxidizing step is completed using an aqueous solution of sodium periodate.
    Type: Grant
    Filed: May 12, 1998
    Date of Patent: August 15, 2000
    Assignee: University of Kentucky Research Foundation
    Inventors: Dibakar Bhattacharyya, Leonidas G. Bachas, Lawrence Cullen, Jamie A. Hestekin, Subhas K. Sikdar
  • Patent number: 5104478
    Abstract: A method for making single crystals, comprising osmotically removing the solvent from a solution containing the material to be grown into a crystal.
    Type: Grant
    Filed: October 17, 1989
    Date of Patent: April 14, 1992
    Assignee: The United States of America as represented by the Secretary of Commerce
    Inventors: Subhas K. Sikdar, Dena L. Lund
  • Patent number: 5066403
    Abstract: The present disclosure is directed to composite membranes formed by casting thin (about 8 to about 20 microns) film of perfluorosulfonic acid (PFSA) polymer on a porous matrix of polytetrafluoroethylene (PTFE). The ion exchange groups in these membranes are protons and can be substituted with metal ions such as Na.sup.+, Ca.sup.+, Ag.sup.+, etc. or by organic ligands. Alternatively, even thinner membranes (from about 1 micrometer or thinner up to 20 micrometers) can be formed by spraying a PPSA polymer solution on a porous matrix. The porous matrix may comprise polytetrafluoroethylene alone or in combination with a thermobonded polypropylene support.Both the acid and the substituted membranes have remarkable affinity for polar compounds or mixtures of polar and non-polar compounds such that azeotropic mixtures of organic compounds as well as close-boiling liquid mixtures can be easily separated at good permeation rates using the technique of pervaporation.
    Type: Grant
    Filed: July 12, 1990
    Date of Patent: November 19, 1991
    Assignee: The United States of America as represented by the Secretary of Commerce
    Inventors: Binay K. Dutta, Subhas K. Sikdar
  • Patent number: 4558118
    Abstract: This invention relates to an improved interfacial polycondensation aromatic polycarbonate process which does not require large quantities of strong base to provide a particulate product. The process is specific to interfacial polycondensation processes wherein the polycarbonate is formed in the aqueous phase by using a low organic to aqueous phase volume ratio. The quantity of strong base required to provide a particular product is reduced by adding the aromatic dihydroxy compound to the reaction mixture in small increments. This maintains a high mole ratio of strong base to aromatic dihydroxy compound during reaction.
    Type: Grant
    Filed: July 20, 1984
    Date of Patent: December 10, 1985
    Assignee: General Electric Company
    Inventor: Subhas K. Sikdar
  • Patent number: 4546207
    Abstract: Anhydrous di-(alkali metal) (especially disodium) salts of dihydroxyaromatic compounds such as bisphenol A are prepared by first contacting the solid dihydroxyaromatic compound with an aqueous alkali metal hydroxide solution so as to convert it into the solid di-(alkali metal) salt or hydrate thereof and subsequently separating the solid salt or hydrate from the aqueous system and removing water therefrom, typically by mixing the same with an organic liquid and removing water, including water of hydration, by evaporation. The organic liquid is preferably one such as toluene or o-dichlorobenzene in which water and the anhydrous di-(alkali metal) salt are substantially insoluble. The process may be operated in batch or continuous fashion.
    Type: Grant
    Filed: July 23, 1984
    Date of Patent: October 8, 1985
    Assignee: General Electric Company
    Inventors: Ashok K. Mendiratta, Subhas K. Sikdar