Transport and Retention of Polyvinylpyrrolidone‐Coated Silver Nanoparticles in Natural Soils

Abstract

Transport and retention of polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) were examined in water-saturated columns packed with three types of natural soils: a clay loam red soil (RS), a sandy loam luvo-aquic soil (FS), and a loam huangni soil (HS). Speciic factors investigated included monovalent K + and divalent Ca 2+ concentrations and the coupled effect of Ca 2+ with humic acid (HA) at a PVP-AgNP concentration of 10 mg L −1 and Darcy velocity of 0.182 cm min −1 . Our results showed that transport of PVP-AgNPs decreased with increasing K + and Ca 2+ concentrations, primarily due to enhanced aggregation of PVP-AgNPs and reduced repulsive interactions between PVP-AgNPs and soil grains. Consistent with the Derjaguin-Landau-Verwey-Overbeek theory, retention of PVP-AgNPs was more pronounced in the presence of Ca 2+ than K + . However, the presence of HA signiicantly weakened the mobility of PVP-AgNPs with increasing Ca 2+ concentration, probably due to increased aggregation of PVP-AgNPs (forming a HA-Ca-PVP-AgNPs complex). Irrespective of solution chemistry, the mobility of PVP-AgNPs in all three soils remained in the order of RS < FS < HS. Principal components analysis indicated that the mobility of PVP-AgNPs was positively correlated with pH, cation exchange capacity, and soil organic matter content and was negatively correlated with Fe oxide content and speciic surface area of the soils. Overall, our indings highlight the dominant role of soil physicochemical properties in the mobility of Ag nanoparticles in natural soils and the importance of investigating these factors to better understand the fate of engineered nanoparticles in natural environments at the point of disposal and protecting groundwater resources.

Nanomaterials in the environment: Behavior, fate, bioavailability, and effects—An updated review

“…Over the last decade, studies of NM transport through soils have progressed from using inert stationary phases (e.g., quartz beads) in columns (Lecoanet et al 2004) to the use of natural soils, so that we now have a much better appreciation of the potential transport of NMs in terrestrial systems (Jaisi et al 2008;Darlington et al 2009;Fang et al 2009;Jaisi and Elimelech 2009;Wang et al 2010;Wang DJ et al 2015;Cornelis et al 2012Cornelis et al , 2013Coutris et al 2012;Sagee et al 2012). The CNTs appear to be retained in soils due to their high aspect ratio, leading to significant straining (Jaisi and Elimelech 2009;Kasel et al 2013).…”

Recent Developments and Applications of the HYDRUS Computer Software Packages

“…The HYDRUS models are increasingly being used also to simulate the fate and transport of various nanoparticles and nanotubes in the environment. For example, Liang et al (2013a,b), Ren and Smith (2013), Cornelis et al (2013), Neukum et al (2014), and Wang et al (2015a) evaluated the sensitivity of the transport and retention of stabilized silver nanoparticles to various physicochemical factors in column studies and undisturbed soil. Kasel et al (2013a,b) and Mekonen et al (2014) evaluated the effects of input concentration, grain size, and saturation on the transport of multiwalled carbon nanotubes.…”

Impact of silver nanoparticles (AgNP) on soil microbial community depending on functionalization, concentration, exposure time, and soil texture

“…AgPure showed similar harmful effects such as Ag10-NH 2 , which could be also attributed to release of Ag + ions. Their low particle concentration, their polyacrylate stabilization and the high pH value of soil could have prevented initial aggregation and agglomeration of AgPure [16,17,73]. In addition, the high concentration of divalent cations, such as Ca 2+ und Mg 2+ in the loamy soil (Table 1) could promote AgPure and Ag10-NH 2 dissolution, resulting in the displacement of Ag + ions from the nanoparticle surface and thus toxicity [74].…”