Mechanistic Insights into Interaction of Humic Acid with Silver Nanoparticles

Abstract

Humic acid (HA) is one of the major components of the natural organic matter present in the environment that alters the fate and behavior of silver nanoparticles (Ag NPs). Transformation of Ag NPs happens upon interaction with HA, thereby, changing both physical and chemical properties. Fluorescence spectroscopy and scanning electron microscopy (SEM) were used to analyze the interaction of Ag NPs with HA. In pH and time-dependent studies, the near field electro dynamical environment of Ag NPs influenced the fluorescence of HA, indicated by fluorescence enhancement. SEM revealed not only morphological changes, but also significant reduction in size of Ag NPs after interaction with HA. Based on these studies, a probable mechanism was proposed for the interaction of HA with Ag NPs, suggesting the possible transformation that these nanoparticles can undergo in the environment.

Understanding the fate and biological effects of Ag- and TiO2-nanoparticles in the environment: The quest for advanced analytics and interdisciplinary concepts

“…In contrast, fluorescence enhancement (Tovmachenko et al, 2006) requires that the fluorophores have distances of 10-25 nm from the EINP surface (Kang et al, 2011). Fluorescence enhancement of HA by metallic nanoparticles was used by Manoharan et al (2014) to understand aggregation and NOM-NP interactions. Pallem et al (2009) distinguished between displacement and overcoating of initial coatings, identifying ligand exchange for HA and D-glucose-coated Au NP and overcoating of citrate coated NP by HA (Pallem et al, 2009).…”

Transformations of Metal Nanoparticles in the Aquatic Environment and Threat to Environmental Safety

“…The impact of nanoparticles on the environment has been studied not only in terms of interactions with NOM [19], [25], [32], [35], [40][41][42][43][44][45][46][47][48] but also in the context of the possibility of aggregation [23], [38], [40][41], [49][50], the impact of pH on nanoparticle transformation [19], [51][52][53][54][55] and the presence and concentration of various inorganic ions [25], [42], [56][57]. Liu et al [56] noticed that in the presence of CaCl�, the formation of ZnO NP aggregates was more effective than for NaCl and KCl [56].…”

“…Oddziaływanie nanocząstek na środowisko badano nie tylko pod kątem interakcji z NOM [19], [25], [32], [35], [40][41][42][43][44][45][46][47][48], ale także pod względem m.in. możliwości występowania agregacji [23], [38], [40][41], [49][50], wpływu pH na przemiany nanoczą-…”

“…SEM studies carried out by Manoharan et al[47] demonstrated that under the influence of humic acid interaction with Ag NPs, these nanoparticles change their physical and chemical properties. The scientists suggested a KH-Ag NP interaction mechanism, which demonstrates that nanoparticles are subject to transformation in the environment.…”

The need for a life-cycle based aging paradigm for nanomaterials: importance of real-world test systems to identify realistic particle transformations

“…Furthermore, the same particle may have different transformation by-products depending on its intended use or purpose. For example, after textile washing, Ag MNM may alter in the tap water, in the wash water, or in the wastewater treatment plant transforming the pristine particle into Ag + [51], AgCl [52], or Ag 2 S [53], respectively, or resulting in re-precipitation of 'new' Ag nanoparticles which may have a different composition and interactions than the parent ones [54,55]. Determining the possible transformation profiles of MNMs is therefore key to understanding their final fate.…”