Metal ion and exopolymer interaction: A surface analytical study

Journal Article · Sun Dec 01 04:00:00 EST 1996 · Corrosion

DOI:https://doi.org/10.5006/1.3292082· OSTI ID:417888

Chen, G; Kagwade, S V; French, G E; Clayton, C R ^[1]; Ford, T E; Mitchell, R ^[2]

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1. State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science and Engineering
2. Harvard Univ., Cambridge, MA (United States). Div. of Applied Sciences

Various concentrations of molybdate (MoO{sub 4}{sup 2{minus}}) were added to the protein-containing and deproteinated exopolymers of the marine bacterium Deleya marina. Interaction was investigated using x-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR). MoO{sub 4}{sup 2{minus}} reduction was observed exclusively in the deaerated protein-containing exopolymer, resulting in the formation of a Mo{sup 5+} species. This species appeared susceptible to reoxidation in the presence of soluble oxygen. Only hexavalent molybdenum (Mo{sup 6+}) was seen in the aerated suspension. The reducing agents may have been the residual proteins that remains in the exopolymer without subsequent deproteination. The influence of this reduction on corrosion resistance of Mo-bearing stainless steels (SS) was simulated with an austenitic type 304 SS (UNS S30400), whose surface was treated with MoO{sub 4}{sup 2{minus}} before exposure to the exopolymer. In addition to formation of the Mo{sup 5+} species, a small amount of molybdenum dioxide (MoO{sub 2}) was detected, and hydration of the passive film increased. No evidence was found to indicate the exopolymer attachment compromised corrosion resistance of the SS in deaerated 0.1 M hydrochloric acid (HCl).

• Sponsoring Organization: Office of Naval Research, Washington, DC (United States)
• OSTI ID: 417888
• Journal Information: Corrosion, Journal Name: Corrosion Journal Issue: 12 Vol. 52; ISSN 0010-9312; ISSN CORRAK
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
BIOLOGICAL FOULING
CORROSION RESISTANCE
ELECTRON SPIN RESONANCE
EXPERIMENTAL DATA
HYDROCHLORIC ACID
MOLYBDENUM IONS
MOLYBDENUM OXIDES
PHOTOELECTRON SPECTROSCOPY
PSEUDOMONAS
REDUCTION
STAINLESS STEEL-304