U.S. patent application number 14/114374 was filed with the patent office on 2014-02-13 for colloidal solution of silver nanoparticles and method of it preparation.
The applicant listed for this patent is Dimitry Sergeevich Dergachev, Boris Sergeevich Kustov, Sergey Alekseevich Nazarov. Invention is credited to Dimitry Sergeevich Dergachev, Boris Sergeevich Kustov, Sergey Alekseevich Nazarov.
Application Number | 20140044763 14/114374 |
Document ID | / |
Family ID | 46724588 |
Filed Date | 2014-02-13 |
United States Patent
Application |
20140044763 |
Kind Code |
A1 |
Kustov; Boris Sergeevich ;
et al. |
February 13, 2014 |
COLLOIDAL SOLUTION OF SILVER NANOPARTICLES AND METHOD OF IT
PREPARATION
Abstract
The invention relates to colloidal solutions of silver
nanoparticles and to method of it preparation and can be used in
different areas, particularly in medicine, veterinary science, food
industry, cosmetology, household chemistry and agrochemistry.
Method includes the electrochemical dissolution of silver in the
deionized water. The silver in fine powder form with chemical
purity of 99.999% and with nanoparticle sizes up to 100 nm is
subjected to electrochemical dissolution in electrolyser, within
which are located the electrodes in form of containers made from
chemically neutral material, in which fine powder of silver from
100 to 150 g are placed, and by means of conductor covered by
chemically neutral coat the direct voltage ranges from 30 to 45
volts is energized. Electrolysis is proceeded under conditions of
cycling voltage polarity every 2 hours and mechanical stirring of
solution 2 times in twenty-four hours until the concentration of
silver in colloidal solution from 5.0 to 100 mg/l. Wherein the
portion of silver metal nanoparticles is from 5 to 90% of total
concentration of silver in solution, the portion of nanoparticles
ranging from 2 to 15 nm is from 65 to 85% of total volume of silver
metal nanoparticles in solution, the portion of nanoparticles
ranging from 15 to 35 nm is correspondingly from 15 to 35%, the
residual portion of total silver concentration in solution is
silver ions. The technical result of invention is preparation of
the stable colloidal solution of silver nanoparticles.
Inventors: |
Kustov; Boris Sergeevich;
(St. Petersburg, RU) ; Dergachev; Dimitry Sergeevich;
(St. Petersburg, RU) ; Nazarov; Sergey Alekseevich;
(St. Petersburg, RU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kustov; Boris Sergeevich
Dergachev; Dimitry Sergeevich
Nazarov; Sergey Alekseevich |
St. Petersburg
St. Petersburg
St. Petersburg |
|
RU
RU
RU |
|
|
Family ID: |
46724588 |
Appl. No.: |
14/114374 |
Filed: |
April 24, 2012 |
PCT Filed: |
April 24, 2012 |
PCT NO: |
PCT/RU12/00309 |
371 Date: |
October 28, 2013 |
Current U.S.
Class: |
424/401 ;
205/704; 424/489; 516/97 |
Current CPC
Class: |
B01J 13/0043 20130101;
C25C 1/20 20130101 |
Class at
Publication: |
424/401 ;
205/704; 424/489; 516/97 |
International
Class: |
C25C 1/20 20060101
C25C001/20 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 29, 2011 |
RU |
2011117472 |
Claims
1. Method of preparation of colloidal solutions of silver
nanoparticles, comprising an electrochemical dissolution of silver
in deionized water, characterized in that, silver in fine dispersed
powder form with chemical purity of 99.999% and with nanoparticle
sizes up to 100 nm is subjected to electrochemical dissolution in
electrolyser, comprising housing made from chemically neutral
material, within which are located the electrodes in form of
containers made from chemically neutral material, in which fine
powder of silver from 100 to 150 g are placed, and by means of
conductor covered by chemically neutral coat the direct voltage
ranges from 30 to 45 volts is energized by means of dc power source
under conditions of cycling voltage polarity every 2 hours and
mechanical stirring of solution 2 times in twenty-four hours until
the concentration of silver in colloidal solution from 5.0 to 100
mg/l, wherein the portion of silver metal nanoparticles is from 5
to 90% of total concentration of silver in solution, the portion of
nanoparticles ranging from 2 to 15 nm is from 65 to 85% of total
volume of silver metal nanoparticles in solution, the portion of
nanoparticles ranging from 15 to 35 nm is correspondingly from 15
to 35%, the residual portion of total silver concentration in
solution is silver ions.
2. The method according to claim 1, characterized in that,
mechanical stirring of solution is performed by the use of solution
contact means made from chemically neutral material.
3. Method according to claim 1, characterized in that, energizing
of the voltage on the silver in form of fine powder is performed by
the use of conductors covered by chemically neutral coat and passed
into electrolyser.
4. Method according to claim 1, characterized in that, additionally
filtering of colloidal solution is performed.
5. Colloidal solution of silver nanoparticles, characterized in
that, it comprise deionized water, silver metal nanoparticles and
have silver concentration from 5.0 to 100 mg/l, wherein portion of
silver metal nanoparticles is from 5 to 90% of total concentration
of silver in solution, the portion of nanoparticles ranging from 2
to 15 nm is from 65 to 85% of total volume of silver metal
nanoparticles in solution, the portion of nanoparticles ranging
from 15 to 35 nm is correspondingly from 15 to 35%, the residual
portion of total silver concentration in solution is silver
ions.
6. Colloidal solution of silver nanoparticles according to claim 5,
characterized in that, it is stable during at least two years.
Description
TECHNICAL FIELD
[0001] The invention relates to inorganic chemistry, mainly to
colloidal solutions of silver nanoparticles and to method of it
preparation and can be used in different areas, particularly in
medicine, veterinary science, food industry, cosmetology, household
chemistry and agrochemistry.
BACKGROUND ART
[0002] For purposes of the clarity of the description some term
definitions are given in the invention.
[0003] The term <<deionized water>> means water without
impurities. The resistivity of such water is up to 18 MOhmcm, the
purity is 99.999%.
[0004] Ion-monatomic or polyatomic electrically charge particle,
forming consequently of loss or attaching one or several electrons
by atom or molecule.
[0005] The term <<silver noble metals>> relates to the
metals of VIII group of Periodical System.
[0006] Silver nanoparticles ranging 1-100 nm can be obtained in
different geometrical forms. This small particles comprise
metal-element in chemically reduced form and, depends on method of
theirs preparation can be stored both in form of reduced solid
powders and in form of stable suspension in solvents, for example,
in water or alcohol (in form of colloids or soles).
[0007] The term <<colloid>> relates to fluid
composition of microscopic particles suspended in liquid medium
(soles). In typical colloids said particles have size in range from
1 nm to 1 micrometer (from 10.sup.-7 to 10.sup.-5 cm). In
transparent colloids dispersion of light ray is observed (Tyndall
effect). Disperse particles are not precipitated at the expense of
Brownian motion.
[0008] Colloidal solutions of silver (i.e. stable system of
<<silver nanoperticles-solvent>>) are painted, this is
physical property of silver nanoparticles, wherein color depends on
size of particles, and <<purity>> of color depends on
homogeneity of particles according to the sizes.
[0009] It is typically for colloids that they are stable in water
solution only if their aggregation is prevented, for example, by
means of stabilizing factors.
[0010] Stabilization of colloidal solutions can be made by adding
small quantity of high-molecular substances that are adsorbed on
the particle surfaces and prevented theirs aggregation.
[0011] It is known the method of preparation of stabilized colloid
(EP patent No. 2007513), comprising the steps of heating of water
up to fist state temperature, adding into water silver nitrate,
heating the mixture up to second required temperature, adding into
mixture lithium citrate followed by heating up to required
temperature, cooling mixture.
[0012] It should be noted that colloid prepared by method described
in EP patent No. 2007513 can be used mainly in Raman
spectroscopy.
[0013] It is known the method of preparation of silver
nanoparticles in liquid medium (RU patent No. 230344) providing
high stability and comprising the steps of solution of stabilizers
in distilled water under stirring, immersing anode made in form of
silver plate into finished solution, and cathode made in form of
stainless steel plate, electrochemical dissolution of anode under
passing the constant regulated current through the solution. The
method described in RU patent No. 2390344 provide high stability of
resulted silver nanoparticles at the expense of stabilizers.
[0014] The silver nanoparticles obtained by the method, described
in the RU patent No. 2390344, is intended to use for the production
of medical, veterinary and cosmetic preparations.
[0015] Thus, the described above technical decisions assisting of
stabilization of colloids are based on the processes, whereby the
colloids were formed due to the previous reaction.
[0016] The closest to the proposed invention on the basis of the
group of essential note and object matter is O.V. MOSIN "Product of
nanotechnology--colloidal silver" on the site
(http://www.sciteclibrary.ru/rus/catalog/pages/9151.html, page 1,
9-10, published Jul. 7, 2008), in which the method of preparation
of the colloidal solution of silver nanoparticles is presented,
comprising electrochemical dissolution of silver in the deionized
water, and it is also presented the colloidal solution of silver
nanoparticles, comprising the deionized water, the silver metal
nanoparticles, and the silver ions.
[0017] An object of the claimed invention is preparation the stable
colloidal solution of silver nanoparticles by the method not
allowing the aggregation of the silver metal nanoparticles without
using of stabilizers.
[0018] The technical result of the claimed invention accomplishing
under use of invention is preparation of stable colloidal solution
of silver metal nanoparticles by the proposed method, in which the
size of silver metal nanoparticles and respectively the weight of
silver metal nanoparticles are such, that the mutual repulsive
force of unipolar dipoles of water surrounding the silver metal
nanoparticles is higher than gravitational forces acting on these
particles, wherewith the keeping of silver metal nanoparticles in
uniformly suspension and in the equal concentration throughout the
volume of solution occurs.
[0019] For solving the object of the invention and achieving
technical result indicated above the group of the inventions united
under general inventor conception is proposed.
[0020] The one of the subject of the proposed invention is method
of preparation of colloidal solutions of silver nanoparticles,
comprising an electrochemical dissolution of silver in deionised
water, characterized in that, silver in fine powder form with
chemical purity of 99.999% and with nanoparticle sizes up to 100 nm
is subjected to electrochemical dissolution in electrolyser,
comprising housing made from chemically neutral material, within
which are located the electrodes in form of containers made from
chemically neutral material, in which fine powder of silver from
100 to 150 g are placed, and by means of conductor covered by
chemically neutral coat the direct voltage ranges from 30 to 45
volts is energized by means of dc power source under conditions of
cycling voltage polarity every 2 hours and mechanical stirring of
solution 2 times in twenty-four hours until the concentration of
silver in colloidal solution from 5.0 to 100 mg/l, wherein the
portion of silver metal nanoparticles is from 5 to 90% of total
concentration of silver in solution, the portion of nanoparticles
ranging from 2 to 15 nm is from 65 to 85% of total volume of silver
metal nanoparticles in solution, the portion of nanoparticles
ranging from 15 to 35 nm is correspondingly from 15 to 35%, the
residual portion of total silver concentration in solution is
silver ions.
[0021] According to method the mechanical stirring of solution is
performed by the use of solution contact means made from chemically
neutral material.
[0022] According to method the energizing of the voltage on the
silver in form of fine powder is performed by the use of conductors
covered by chemically neutral coat and passed into
electrolyser.
[0023] According to method the additionally filtering of colloidal
solution is performed.
[0024] The another subject of the proposed invention is colloidal
solution of silver nanoparticles, characterized in that, it
comprise deionized water, silver metal nanoparticles and have
silver concentration from 5.0 to 100 mg/l, wherein the portion of
silver metal nanoparticles is from 5 to 90% of total concentration
of silver in solution, the portion of nanoparticles ranging from 2
to 15 nm is from 65 to 85% of total volume of silver metal
nanoparticles in solution, the portion of nanoparticles ranging
from 15 to 35 nm is correspondingly from 15 to 35%, the residual
portion of total silver concentration in solution is silver
ions.
[0025] According to the invention the colloidal solution of silver
nanoparticles is stable during at least two years.
[0026] It should be noted that in the general concentration of
silver in the solution the portion of silver metal nanoparticles is
from 5 to 90% depending on tasks (sphere of the use of the finished
product).
[0027] During the research process were selected the parameters of
the method of preparation of the colloidal solution of silver
nanoparticles on the basis of the electrolysis rate and the time of
process, which is directly proportional to the volume of
electrolyzer and to a quantity of fine dispersed powder of silver
placed into the electrolyzer, and is inversely proportional--to
voltage supplied to the electrodes. It was also established that
sizes of silver nanoparticles in the solution and their quantity
with respect to silver ions are in direct dependence from the
frequency of the change of polarity and from the frequency of
mechanical stirring. It is important to note that according to the
results of performed investigations the obtained colloidal solution
of silver nanoparticles keeps stability during, at least, two years
without the addition of stabilizing chemical, biological and other
components, and without the physical stabilization.
[0028] It should be noted that filtration of colloidal solution of
silver nanoparticles additionally is performed for preparation of
colloidal solution of silver nanoparticles with given
concentration. The step of filtration can be performed, if it is
necessary to obtain solution with the given size of particles (for
example, not more than 10 nm).
[0029] Invention is illustrated by an example of the method of
preparation of colloidal solution of silver nanoparticles.
BEST MODE FOR CARRYING OUT THE INVENTION
[0030] Example of the method of preparation of the stable colloidal
solution of silver nanoparticles.
[0031] In the process of preparation of colloidal solution of
silver nanoparticles is used: the deionized water obtained by the
multistage filtration after which the conductivity of purified
water must be not more than 0.3 mS/Sm (microsiemens/centimeter); to
electrochemical dissolution is subjected silver in the form of fine
dispersed powder with chemical purity of 99.999% and sizes of the
particles of the powder up to 100 nm.
[0032] The deionized water is moved into the electrolyzes made in
the form of the capacity having a volume of 5 liters and more (20
liters), from the chemically neutral material (for example,
chemically neutral glass--NC-3, polyethylene of high pressure,
fluorocarbon polymer).
[0033] For the protection of the entry of dust and other small
particles on top the capacity is capped. Inside the housing are
located the containers, made from chemically neutral material, in
which fine powder of silver from 100 to 150 g are placed (to the
volume of the electrolyzes of 20 liters). Containers with fine
powder are electrodes. Constant voltage in the optimum
(experimentally established) range from 30 to 45 volts by means of
the source of power of direct current is supplied to the electrodes
by means of the conductor covered by chemically neutral coat. The
change of polarity is produced with the periodicity 2 hours.
Stirring of solution is achieved by a mechanical method (for
example, with the use of a peristaltic pump and hoses lowered in
the electrolyzer in the opposite angles at different depth)
periodically 2 times in twenty-four hour period for preventing the
formation of large particles in the space between the containers
with silver and for the purpose of preventing obtaining ionic
solution.
[0034] As a result is obtained the colloidal solution of silver
nanoparticles with total concentration of silver in the ranges from
5.0 mG/l (lower than said value--not to measure) to 100.0 mG/l
(higher than the said value--not to obtain because of the
aggregation of particles).
[0035] In the obtained colloidal solution the portion of the silver
metal nanoparticles is from 5 to 90% of the total concentration of
silver in the solution, the portion of nanoparticles ranging from 2
to 15 nm is from 65 to 85% of the total volume of the silver metal
nanoparticles in the solution, the portion of nanoparticles ranging
from 15 to 35 nm is respectively from 15 to 35%, the residual
portion of total concentration of silver in the solution is silver
ions, which is confirmed by the performed laboratory researches.
Namely, the total concentration of silver in the solution was
determined by the method of mass-spectroscopy (by means of the
atomic-emissive spectrograph with the inductively coupled
plasma--ICP OES). Ion concentration of silver in the solution was
determined by means of the ion-selective electrodes. The
concentration of the silver metal nanoparticle in the solution and
their size distribution were determined by means of an instrument
of Zetasizer Nano of the company Malvern.
[0036] Obtained by this method colloidal solution of silver is
transparent. The absence of color is the indirect confirmation of
the fact that a basic quantity of nanoparticles in the volume of
solution has a size of less than 15 nm.
[0037] For preparation of the colloidal solution of silver
nanoparticles with given size of particles (for example, not more
than 10 nm) is performed it filtration. Filtration performed by
means of sterile micro-filters with given selectivity according to
the size of the passed particles, for example, MILLEX GP of firm
Millipore.
[0038] The obtained colloidal solution of silver nanoparticles is
poured into the storage capacity. Solution is subject to storage at
room temperature both in the presence of ultraviolet radiation and
in the darkness without the aggregation during, at least, the 2
years (according to the results of the experiments, carried out by
FGUN <<The institute of the toxicology>> of FMBA of
Russia). The colloidal solution of silver nanoparticles save
stability (according to the results of the experiments, carried out
by FGUN <<The institute of the toxicology>> of FMBA of
Russia) during, at least, the 2 years without the addition of
stabilizing chemical, biological and other components and physical
stabilization.
[0039] Freezing the colloidal solution of silver nanoparticles (to
the complete solid aggregative state) and its subsequent thawing,
(as shows the results of the carried out experiments in FGUN
<<The institute of the toxicology>> of FMBA of Russia)
does not affect the stability of solution, and it does not change
its properties.
[0040] Thus, the example, which illustrates invention, clearly
confirms that under specific parameters of method procedure
selected during the research is performed the stable colloidal
solution of silver nanoparticles, in which the sizes and the
properties of the surface of forming silver nanoparticles prevent
subsequently of their coagulation. The performed by the proposed
method colloidal solution of silver nanoparticles can be used in
medicine, veterinary science, cosmetilogy, household chemistry and
agrochemistry, and also in the food industry.
* * * * *
References