**EXHIBIT
      10.52**





**MODIFICATION
      AGREEMENT**





This
      Modification Agreement (the “Agreement”) is made as of November 28, 2007 among
      SulphCo, Inc. (“Maker”) and Ellis Capital LLC, Mayflower Oak LLC, Iroquois
      Master Fund Ltd., Scot Cohen, Scott Jason Cohen Foundations, Inc., Merav Abbe
      Irrevocable Trust, Edward G. Rosenblum, Devidas Budrani, Joshua Silverman and
      Phil Mirabelli (each a “Holder” and collectively “Holders”).





WHEREAS,
      the Maker, Rudolph Gunnerman and Holders entered into that certain Assignment
      (“Assignment”) of Promissory Notes (“Notes”) and Allonge to Promissory Notes
      (“Allonge”), each dated April 27, 2007; and





WHEREAS,
      it is in the interest of the parties to amend the terms of the Notes and
      Allonge.





NOW
      THEREFORE, in consideration of the mutual promises and covenants set forth
      in
      this Agreement, and intending to be legally bound hereby, it is agreed as
      follows:





1.  Paragraph
      I of the Allonge shall be amended as follows:





“I. Maturity
      Date and Additional Interest Payment Date .
      The
      Maturity Date shall mean December 31, 2011, and interest shall be payable on
      December 31 st of each
      year during the term of the Note.”





2.  The
      following provisions shall be added to paragraph I of the Allonge:





(a)  Holder
      shall have the right to accelerate the Maturity Date of the Note upon ten (10)
      business days prior written notice to any date after July 31, 2009.





(b)  Maker
      shall have the option of prepaying the outstanding principal amount of the
      Note.
      Maker’s election to exercise its right to prepay must be by notice in writing
      which payment date shall be at least ten (10) business days after the date
      of
      the notice and during which time the Holder shall have the right to convert
      any
      portion or all of its Note.





3.  The
      following provision shall be added as paragraph 4.8 to the Allonge:





“Notices.
      All notices and other communications given or made pursuant to this Allonge
      shall be in writing and shall be deemed effectively given: (a) upon personal
      delivery to the party to be notified, (b) when sent by confirmed electronic
      mail
      or facsimile if sent during normal business hours of the recipient, and if
      not
      so confirmed, then on the next business day, (c) five (5) business days after
      having been sent by first class mail, postage prepaid, or (d) one (1) business
      day after deposit with a nationally recognized overnight courier, specifying
      next business day delivery, with written verification of receipt.”





4.  All
      other
      terms and conditions of the Assignment, Notes and Allonge shall remain in full
      force and effect.





5.  This
      Agreement may be executed in two or more counterparts, all of which when taken
      together shall be considered one and the same agreement and shall become
      effective when counterparts have been signed by each party and delivered to
      any
      other party, it being understood that all parties need not sign the same
      counterpart. In the event that any signature is delivered by facsimile
      transmission, such signature shall create a valid and binding obligation of
      the
      party executing (or on whose behalf such signature is executed) the same with
      the same force and effect as if such facsimile signature were an original
      thereof.





6.  Each
      of
      the undersigned states that he has read the foregoing Agreement and understands
      and agrees to it.





SULPHCO.,
                INC.By:
            ___________________________________





**“HOLDERS”**





______________________________________
            
            ___________________________________ELLIS
                CAPITAL LLC
            
            MAYFLOWER
                OAK LLC______________________________________
            
            ___________________________________IROQUOIS
                MASTER FUND LTD.
            
            SCOT
                COHEN______________________________________
            
            ___________________________________SCOTT
                JASON COHEN FOUNDATION INC.
            
            MERAV
                ABBE IRREVOCABLE TRUST______________________________________
            
            ___________________________________EDWARD
                G. ROSENBLUM
            
            DEVIDAS
                BUDRANI______________________________________
            
            ___________________________________JOSHUA
                SILVERMAN
            
            PHIL
                MIRABELLI