Removal of silver in photographic processing waste by TiO{sub 2}-based photocatalysis

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es960167l· OSTI ID:420780

Huang, M; Tso, E; Datye, A K ^[1]; Prairie, M R; Stange, B M ^[2]

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1. Univ. of New Mexico, Albuquerque, NM (United States)
2. Sandia National Lab., ALbuquerque, NM (United States)

Treatability data on actual waste show that titania-based photocatalysis can be used to remove silver ions from black and white photoprocessing waste. The silver ion is reduced to its metallic form producing particles comparable in size to the TiO{sub 2} catalyst particles. The mass of silver recovered approaches three times that of the titania. Thiosulfate (the predominant chemical in spent fixer) plays a complicated role in the process of silver ion reduction: (1) as a hole scavenger, it can increase the silver reduction rate; (2) as the chemical that stabilizes silver ion in solution, thiosulfate hinders photocatalysis when present at high concentration. Metallic silver can be separated from titania by the physical process of sonication. We also show that sunlight can be used directly to power the photo-electrochemical silver removal process. 11 refs., 9 figs.

• Research Organization: Sandia National Laboratory
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 420780
• Journal Information: Environmental Science and Technology, Journal Name: Environmental Science and Technology Journal Issue: 10 Vol. 30; ISSN 0013-936X; ISSN ESTHAG
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
54 ENVIRONMENTAL SCIENCES
AQUEOUS SOLUTIONS
CATALYSIS
PHOTOCHEMICAL REACTIONS
PHOTOGRAPHY
REDUCTION
REMOVAL
SILVER
SILVER IONS
THIOSULFATES
TITANIUM OXIDES
WASTE PROCESSING
WASTE WATER