Аннотация:At present, there has been a steady increase in the production of nanomaterials
possessing unique properties such as thermal, optical, physical, chemical, magnetic etc.
One of the most preferred nanoparticles are silver ones (AgNP) due to their active use
primarily as a universal antiseptic agent inhibiting the growth of pathogenic
microorganisms. The major drawback of AgNP fabrication is a use either high energyconsuming
physical processes or toxic compounds (organic solvents, reducing agents and
stabilizers) in their synthesis [1]. In the case of AgNP is especially critical, since the
residual content of toxic reagents prevents the application of AgNP for medical purposes.
Therefore, increasing attention is paid to the search for alternative ways of synthesis of
AgNP using environmentally friendly technologies. Our work aimed at study of AgNP
formation in the presence of humis substances (HS) of different origin. This approach is
based on simulation of Ag+ interaction with in the environment.
To reach this goal, synthesis of AgNP in the presence of HS was carried out at 25C
under 12-h photoperiod. Silver ions was introduced as AgNO3 to reach final concentration
0.01 M, and concentration of HS was 1 g/L. Ten HS of different origin including soil, peat
and coal humic acids (HA) and fulvic acids (FA) were used. HS were described using
elemental analysis, gel permeation chromatography and 13C NMR. AgNP formation was
monitored using UV/Vis spectrophotometry, and the end Ag+ – HS interaction was
detected when peak corresponding AgNP at ca. 400 nm stopped its growth. In parallel, pH
and Eh were monitored during all over the experiment.
Our results showed different rate of AgNP formation in the presence of HS
depending HS properties reaching maximum in case with sod-podzolic soil FA and
minimum in case with HA extracted from chernozem while peat and coal HS demonstrated
intermediate rates. In general, higher rate was observed for HS with greater content of
aliphatic moieties in their structure.
During AgNP formation values of Eh increased from ca. 0.2 to ca. 0.5 V indicating the
oxidation of HS. Together with Eh growth, substantial pH decrease was detected.
Therefore, carboxylic group formation in the HS structure could be hypothesized during
AgNP formation.
References
1. Shah M., Fawcett D., Sharma S., Tripathy S. K., Poinern G. E. J. Green Synthesis
of Metallic Nanoparticles via Biological Entities // Materials. 2015. 8:7278–7308.
doi:10.3390/ma8115377.
This research was supported by the Russian Science Foundation grant 16-14-00167.