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Purification system

  • US 5,554,300 A
  • Filed: 02/22/1995
  • Issued: 09/10/1996
  • Est. Priority Date: 02/22/1995
  • Status: Expired due to Term
First Claim
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1. A method for purifying a contaminated fluid by photocatalytic treatment, comprising:

  • (a) providing a contaminated fluid including contaminant molecules in the presence of a photocatalyst;

    (b) exciting said photocatalyst with ultraviolet light to form photocatalyst conduction band electrons and positive holes thereby inducing an oxidation state whereby some contaminant molecules are oxidized;

    (c) inducing a reduction state, in the substantial absence of oxidizing agents that compete for said photocatalyst conduction band electrons, by adding a reactant comprising a carboxylic acid in sufficient quantity to provide surrogate electrons that react with said positive holes formed on the photocatalyst while the semiconductor catalyst is irradiated whereby other contaminant molecules are reduced by said photocatalyst conduction band electrons.

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