ABSTRACT
This study aims to characterize nanoparticles with different compositions and structures as well as seeing their evolutions over time in a natural environment such as Seine river water (Paris, France). Face centered cubic (fcc) and hexagonal (hcp) CdS as well as hexagonal (hcp) ZnO nanoparticles were synthesized by the Polyol method. CdS nanoparticles (i) cfc structure: are agglomerated, present 100 nm length with heterogeneous diameter and 10 m2 g(-1) specific surface area (S(g)) from Brunauer Emett and Teller (BET) measurements; (ii) hcp structure: 20 nm and S(g) = 67 m2 g(-1). ZnO hcp nanoparticles presents 50 nm length and 15 nm diameter and S(g) = 54 m2 g(-1). These results are in agreement with X-ray diffraction (XRD), and small angle X-ray scattering (SAXs). After 48 h interaction with Seine river water, cryo-TEM analysis showed that ZnO nanoparticles form spherical agglomerates with 300 nm diameter; CdS nanoparticles (fcc) are agglomerated presenting large diameters (> 500 nm); and CdS nanoparticles (hcp) are not agglomerated and present the same characteristics of the starting material. After 168h of contact with Seine river water, CdS (fcc) presents only 14% of dissolution, CdS (hcp) presents both 60% dissolution and 30% reprecipitation in a cadmium carbonate form and finally almost 90% of ZnO nanoparticles are dissolved.
Subject(s)
Cadmium Compounds/chemistry , Metal Nanoparticles/chemistry , Polymers/chemistry , Rivers/chemistry , Sulfides/chemistry , Zinc Oxide/chemistry , Hydrogen-Ion Concentration , Paris , Scattering, Small Angle , X-Ray DiffractionABSTRACT
Silver nanostructured films were directly prepared by spray deposition of preformed polyol-based Ag-PVP nanoparticles. These homogeneous films of high optical quality were tested as SERS-active substrates. Laser excitation at 514.5 nm within the red part of the plasmon band leads to intense and reproducible SERS spectra of acridine, used as the probe molecule. From SERS measurements at different pH values, it was possible to determine the apparent pK(a) of acridine and to obtain specific surface properties of the film. Finally, these SERS titrations along with enhancement factor estimates allowed us to further depict the nature of the films.
