Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 4, pp. 545−548.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
D.S. Sal’nikov, A.S. Pogorelova, S.V. Makarov, I.Yu. Vashurina, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82,
No. 4, pp. 552−555.
INORGANIC SYNTHESIS AND INDUSTRIAL
Silver Ion Reduction with Peat Fulvic Acids
D. S. Sal’nikov
, A. S. Pogorelova
, S. V. Makarov
, and I. Yu. Vashurina
Ivanovo State Chemicotechnological University, Ivanovo, Russia.
Institutes of Solution Chemistry, Russian Academy of Sciences, Ivanovo, Russia
Received April 8, 2008
Abstract—Formation of silver nanoparticles in chemical reduction of AgNO
with peat fulvic acids in an aqueous
alkali solution was studied spectrophotometrically. The size of the resulting nanoparticles and their stability were
examined in relation to the reaction temperature and time,and concentrations of fulvic acids and silver nitrate.
Nanotechnologies represent one of the key directions
in development of science and technology, which yield
materials with unique physical, chemical, and biological
properties . Increased interest in nanosize silver is
dictated by the promises of its antibacterial and antiviral
applications [2, 3]. There exist several methods of
preparation of silver nanoparticles, in particular, chemical
Today, a topical issue is the search for new reducing
agents to prepare nanosize silver. The preference among
these agents is given to natural environmentally safe
compounds like arabinogalactan (polysaccharide)  and
quercetin (ﬂ avonoid) . These compounds owe their
reducing power to the aldehyde and phenolic groups in
their molecules, respectively.
Here, we demonstrate that reducing agents for
preparation of nanosilver can be found in environmentally
safe natural biopolymers, peat fulvic acids. The
corresponding method of preparation of the nanomaterial
is simple and easily implemented. Combined with
physiological activity of fulvic acids proper [10, 11],
this offers promise for synthesis of new bactericides for
various technical and medicinal applications.
We used chemically pure-grade silver nitrate and
an aqueous solution of fulvic acids isolated from high-
type cotton grass-sphagnum peat by alkaline extraction
with sodium hydroxide by a standard procedure .
The alkaline extract of peat, containing humic and
hymatomelanic acids along with fulvic acids, was
acidiﬁ ed to pH 1. This caused precipitation of humic and
hymatomelanic acids, which were subsequently separated
from fulvic acids by ﬁ ltration. The concentration of fulvic
acids in solution was determined gravimetrically. The
solutions of fulvic acids were alkalized with chemically
pure-grade sodium hydroxide to pH 6.5, in which medium
the reduction reaction was run. The temperature was
varied within 25–90°C. The absorption spectra were
recorded on a Specord M-40 spectrophotometer.
Fulvic acids belong to one of the fractions of humus
acids, along with humic and hymatomelanic acids.
Structurally, humus acids are distinguished by a broad
spectrum of groups and moieties they contain. Of
greatest value among them are oxygen-containing groups,
speciﬁ cally phenolic, carboxy, alcoholic, and aldehyde, as
well as ketone and quinone groups. Also, the molecules
of humus acids contain amino acid and carbohydrate
residues, as well as ﬂ avonoid moieties [11, 13].
Fractionation of humus acids is underlain by the
difference in the solubility of fulvic, humic, and hymato-
melanic acids in acids and alkalis [11–13]. Fulvic acids
represent a fraction soluble both in alkalis and acids.
Compared to humic acids, fulvic acids have a lower
molecular weight, a less aromatic molecular structure, and
increased content of oxygen-containing groups. Fulvic
acids actively participate in diversified interactions,
including redox processes [14–17]. Thus, simple
preparation technology and readily accessible inexpensive
raw material, as well as nontoxicity, environmental
safety, and broad spectrum of properties of peat fulvic