The particle diameters of AgNPs decreased
approximately 10% during a ten-day period in both of the
naturalwater and effluentwater (Fig. 9(a)). It indicated that dissolution
occurred when AgNPs were dispersed in environmental water at low
number concentration. This was consistentwith the results of Furtado's
study (Furtado et al., 2014). The interactions between particleswere infrequent
at low concentrations limiting the rate of homoagglomeration
(Furtado et al., 2015). Ag+ was then released into solution through the
oxidation and dissolution of AgNPs (Li and Lenhart, 2012). Dissolution
happened when AgNPs were dispersed in synthetic water (Table SI-3).
As for AuNPs, both of the 60 nm and 100 nm AuNPs spiked into the two waters were relatively stable (Fig. 9(b)). It indicated that no dissolution
or aggregation happened when gold nanoparticles were spiked
into the environmental water at low number concentration. AuNPs
was also stable in synthetic matrix (Table SI-4). Dan (Dan et al., 2015)
pointed out that AuNPs can be extracted from tomato tissues as intact
particles and no dissolution or aggregation happened after tomato
plants being exposed to 5 mg/L of 40 nm AuNPs for 4 days. And
AuNPs capped with PVP do not aggregate at environmental relevant