Silver nanoparticles (Ag-NPs) readily transform in the environment, which modifies their properties and alters their transport, fate, and toxicity. It is essential to consider such transformations when assessing the potential environmental impact of Ag-NPs. This review discusses the major transformation processes of Ag-NPs in various aqueous environments, particularly transformations of the metallic Ag cores caused by reactions with (in)organic ligands, and the effects of such transformations on physical and chemical stability and toxicity. Thermodynamic arguments are used to predict what forms of oxidized silver will predominate in various environmental scenarios. Silver binds strongly to sulfur (both organic and inorganic) in natural systems (fresh and sea waters) as well as in wastewater treatment plants, where most Ag-NPs are expected to be concentrated and then released. Sulfidation of Ag-NPs results in a significant decrease in their toxicity due to the lower solubility of silver sulfide, potentiall...

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Environmental transformations of silver nanoparticles: impact on stability and toxicity.

Electrochemical corrosion of unalloyed copper in chloride media––a critical review

The corrosion of nickel–aluminium bronze in seawater

Publisher Summary Microorganisms play a significant role in the corrosion process. This chapter reviews the deterioration or corrosion of metals induced by the activities of microorganisms. The microorganisms which have been associated with corrosion involve many genera and species. They may be divided into three groups: bacteria, fungi, and algae. The most important bacteria that play a significant role in the corrosion process are those involved in the sulfur cycle. These include those involved in the oxidation as well as in the reduction of sulfur. Of these two groups, the sulfate reducing bacteria (SRB) are the most significant bacteria found in microbial corrosion processes. A fungus, Cladosporium resinae, found to be involved in the corrosion of aluminum integral to fuel tanks of subsonic aircraft, leading to wing perforation and loss of fuel. It is now believed that the aluminum corrosion is caused by carboxylic acid production. Algae appear to have the potential for inducing corrosion by virtue of their role in production of oxygen, corrosive organic acids, and nutrients for other corrosive microorganisms. It is found that in areas where there is decay of the mat the pH was lowered, probably due to the production of corrosive organic acids, causing differential pH corrosion cells as well. Conditions were also found to be rendered favorable for the growth of SRB.

Microbial Corrosion of Metals

Surface characterization and corrosion behavior of 70/30 Cu-Ni alloy in pristine and sulfide-containing simulated seawater

The accelerated corrosion of CuNi alloys in sulphide-polluted seawater: Mechanism no. 2

: We have investigated the importance and effects of various variables on the corrosion mechanism of two copper/nickel alloys, CA706 (90%Cu-10%Ni) and CA715 (70%Cu-30%Ni) in seawater. The variables investigated were dissolved oxygen content, sulfide content, pH, flow velocity, sulfide preexposure, various sulfide species, and simultaneous exposure to sulfide and oxygen. The presence of sulfide in seawater was found to prevent formation of the protective corrosion product that normally forms on copper/nickel alloys, Therefore, when both sulfide and oxygen were present in the seawater, the corrosion of the alloys was greatly accelerated. A qualitative model was developed to explain the mechanism of uniform corrosion of copper/nickel alloys in various seawater environments. (Author)

https://apps.dtic.mil/sti/pdfs/ADA096865.pdf

L. E. Eiselstein

Papers

The accelerated corrosion of CuNi alloys in sulphide-polluted seawater: Mechanism no. 2

Mechanisms of Corrosion of Copper-Nickel Alloys in Sulfide-Polluted Seawater

The accelerated corrosion of copper-nickel alloys in sulfide-polluted seawater: mechanism no. 2