A Raman-Based Imaging Method for Characterizing the Molecular Adsorption and Spatial Distribution of Silver Nanoparticles on Hydrated Mineral Surfaces

Abstract

Although minerals are known to affect the environmental fate and transformation of heavy-metal ions, little is known about their interaction with the heavily exploited silver nanoparticles (AgNPs). Proposed here is a combination of hitherto under-utilized micro-Raman-based mapping and chemometric methods for imaging the distribution of AgNPs on various mineral surfaces and their molecular interaction mechanisms. The feasibility of the Raman-based imaging method was tested on two macro- and microsized mineral models, muscovite [KAl(AlSiO)(OH)] and corundum (α-AlO), under key environmental conditions (ionic strength and pH). Both AgNPs and AgNPs were found to covalently attach to corundum (pH = 9.1) through the formation of Ag-O-Al- bonds and thereby to potentially experience reduced environmental mobility. Because label-free Raman imaging showed no molecular interactions between AgNPs and muscovite (pH = 7.5), a label-enhanced Raman imaging approach was developed for mapping the scarce spatial distribution of AgNPs on such mineral surfaces. Raman maps comprising of n = 625-961 spectra for each sample/control were rapidly analyzed in Vespucci, a free open-source software, and the results were confirmed via ICP-OES, AFM, and SEM-EDX. The proposed Raman-based imaging requires minimum to no sample preparation; is sensitive, noninvasive, cost-effective; and might be extended to other environmentally relevant systems.

Wrinkled Reduced Graphene Oxide Supported Nano Ag4Bi2O5 Rods as Greatly Enhanced Catalyst for Zinc-Air Battery

“…In this composite, wrinkled structure of rGO will not only effectively support the nano Ag 4 Bi 2 O 5 rods, but also increase the surface area, resulting in uniform dispersion and improvement of oxygen reduction ability. 45,46 For graphene based materials, two distinctive peaks are located at 1350 and 1595 cm −1 , implying the hybrid of sp 3 disordered carbon (D-band) and sp 2 graphitized carbon (G-band), respectively. 47 It is noticeable that ongoing from rGO to ABO/rGO, the D and G band peaks are broadened and weaken.…”

Facile co-sintering process to fabricate sustainable antifouling silver nanoparticles (AgNPs)-enhanced tight ceramic ultrafiltration membranes for protein separation

“…This indicates that the AgNPs could be partly introduced substitutionally, providing a slight increase in the VAl‴ concentration and thus a lower electronic cloud density [7]. This demonstrates that the Al-O-Ag chemical bonds are formed [51][52][53] between the alumina particles and AgNPs.…”

Accumulation of Ag(0) Single Atoms at Water/Mineral Interfaces during Sunlight-Induced Reduction of Ionic Ag by Phenolic DOM

“…We noticed that in the previous research on secondary AgNPs formation, the resolution of the characterization techniques, such as transmission electron microscope (TEM), was often low, and that the reactions occurred homogeneously. , Therefore, any subnanometer species was not observed. In addition, Ag-SAs in homogeneous solutions should be extremely unstable because of their high surface energy associated with atomic dispersion, and thus promptly decay to nuclei after formation. , In contrast, diverse forms of Ag naturally interact with both mineral surfaces and DOM under real-world conditions. , Consequently, both the minerals’ interface and DOM could bring about significant influence on the stability of all Ag species, particularly Ag-SAs.…”

“…13,14 In contrast, diverse forms of Ag naturally interact with both mineral surfaces and DOM under real-world conditions. 15,16 Consequently, both the minerals' interface and DOM could bring about significant influence on the stability of all Ag species, particularly Ag-SAs.…”