Reduction and amalgamation of mercury in silver nanoparticle suspensions under dark conditions

Mercury (Hg) is a global pollutant of concern, and its transport and transformation are controlled by various environmental factors, with aquatic particles being an important driver. Understanding the interactions between silver nanoparticles (AgNPs) and Hg under dark condition is a prerequisite for studying the extent of AgNPs interaction with light and its participation in Hg biogeochemical cycling. Herein, under laboratory experimental setting, it was found that the reduction of divalent Hg (Hg(II)) to gaseous elemental Hg (Hg0) by AgNPs readily occurred. Within 30 min, less than 20% of Hg(II) were reduced to Hg0, with more than 80% remaining in solution. The Hg0 generated distributed between AgNPs and aqueous phase with very small amount (