This study investigated how silver nanoparticles (AgNP) and ionic silver (AgNO 3 ) undergo phase-transformations in soils under aerobic and anaerobic conditions using extended X-ray absorption fine structure (EXAFS) spectroscopy. After 30 days of aerobic incubation, 88% of AgNP added to the soil remained persistent, whereas AgNO 3 was completely transformed into Ag associated with humus and clay minerals. In the anaerobic soil, 83% of the spiked AgNP was transformed into Ag 2 S, accompanied by significant decrease in water- and acid-extractable Ag fractions. About 50% of AgNO 3 spiked to the anaerobic soil underwent transformations into metallic Ag and associations with clay minerals. Oxide (Ag 2 O) and carbonate (Ag 2 CO 3 ) forms of Ag were not predominant in aerobic and anaerobic soils. The redox potential of soil had a profound effect on determination of the phase-transformation pathways for AgNP and ionic Ag.
- Chemical speciation
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Waste Management and Disposal
- Health, Toxicology and Mutagenesis