Method of removing organic materials using aqueous cleaning solutions

Abstract

The pharmaceutical, fine chemical, and construction industries have aggressively sought means of eliminating organic solvents from their cleaning operations because many organic cleaning solvents have been characterized as hazardous or toxic wastes. As a substitute, 3% hydrogen peroxide (H2O2) in water effectively removed tenacious residues from glass surfaces. In order to simulate industrial cleaning conditions, asphalt was employed as a representative surrogate for tough-to-clean residues. Asphalt cleaning was dramatically enhanced by mild heating: whereas 3% H2O2 at pH 9.5 and 23° C. removed 100% of a fresh asphalt residue within 60 minutes, heating to 53° C. achieved full removal within 2 minutes. As asphalt became aged or dried by exposure to air, longer cleaning durations were required. None-the-less, all of the asphalt could still be removed with 3% H2O2 at pH 9.5 and 70° C. within 2 to 60 minutes, even after the asphalt had dried onto glass for a week. H2O2 removed asphalt even when visible light was not present. When the H2O2 was excluded, a pH 9.5 bath at 70° C. removed only a small fraction of this asphalt, if any.

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