УДК 54.576.851.513(575.2)
Виноградов В.В., Касымова Э.Дж.
ПОЛИМЕРДИК ГИБРИДДИК МАГНИТТИК-АКТИВДҮҮ
СОРБЕНТТЕРДИН СИНТЕЗИ
АННОТАЦИЯ.Бул иште магниттикнанобөлүкчөлөр (МНБ) магнетиттин эритмелеринин
каныгууларынын эсептери сунушталган, алардын өлчөмүно карата жана гумин
кислоталарынын (ГК) молекуласынын максималдуу өлчөмүно жараша. Алардын негизинде
гуминдик кислоталар менен композиталынган.Удаалаш химиялык кадамдар аркылуу
композиттин жардамы менен полимердик гибриддик магниттик-активдүү сорбенттер
иштелип алынган, алар аныкталган темир ионуна карататандалган жутууга ээ.
УРУНТТУУ СӨЗДӨР: гуминдик кислоталар, магниттик нанобөлүкчөлөр, магнетит,
селективдүү сорбенттер.
УДК 54.576.851.513(575.2)
Виноградов В.В., Касымова Э.Дж.
СИНТЕЗ ПОЛИМЕРНЫХ ГИБРИДНЫХ
МАГНИТОАКТИВНЫХ СОРБЕНТОВ
АННОТАЦИЯ. В настоящей работе представлены расчеты концентраций растворов
магнитных наночастиц (МНЧ) магнетита в зависимости от их размера и максимального
размера молекулы гуминовых кислот (ГК). На их основе с гуминовыми кислотами
синтезирован композит. При проведении последовательных химических стадий на
композите получены полимерные гибридные магнитоактивные сорбенты, обладающие
селективной сорбцией по отношению к определенному иону металла.
КЛЮЧЕВЫЕ СЛОВА: гуминовые кислоты, магнитные наночастицы, магнетит, селективные
сорбенты.
UDC 54.576.851.513(575.2)
Vinogradov V.V., Kasymova E.J.
SYNTHESIS OF POLYMER HYBRID MAGNETICALLY SORBENTS.
ANNOTATION. This paper presents calculations of solution concentration of magnetic
nanoparticles (IPM) magnetite, depending on their size and the maximum size of the molecules of
humic acid (HA). On this basis, together with humic acids composite is synthesized. During the
sequential chemical steps on the composite magnetically hybrid polymer sorbents, having selective
sorption with respect to a particular metal ion, have been obtained.
KEYWORDS: humic acids, magnetic nanoparticles, magnetite, selective sorbents.
It is known [1-3] that the greatest resistance have the magnetic particles in the size of the
order of d0 ~ 10 nm, which do not stick by its own magnetic moment. When HA surface coating
magnetic particles can be made larger, while their magnetic susceptibility per unit mass increases.
Calculations should be made for the size close to 10 nm, as a result of the research found that the
size of the obtained magnetic particles is 15 nm, the basic calculation is made for the radius of 7.5
nm. According to our proposed method of preparing magnetic particles took 50 ml of a solution of
iron chloride and 2-3-valent, then poured into 20 ml of 5% ammonia solution, 70 ml of the slurry
obtained magnetite Fe3O4 containing 1 g (14.29 g / l). It is necessary to calculate whether the humic
acid molecule can simultaneously bind two magnetite particles together?
We have defined the size of HA that matches the size of the core molecule. It is believed
that the main fraction of HA has Mr = 1300-1400c.u. [4]. The following table shows the sample HA
analysis, elemental composition of carbon, oxygen, nitrogen, hydrogen and sulfur, excluding a
given ash content.
Table 1. The elemental composition of the HA sample
[Al2O3] * [SiO2] - ash average molecular weight of 162 c.u.
Mass. %
Preparation
HA
C
H
N
S
O
Ash, %
63,93 4,07 1,17 0,33 30,50 7,14
Acidity, [ммоl/g]
ArCOOH Ar-OH
CHO
5,00
2,40
1,44
22,5
4,08
4,02
Therefore from the table, you can write the average empirical formula of humic acid
{S5,3O1,9N4N0,08 S0,01 [Al2O3 * SiO2] 0,04}a.
It is known [4], that the magnetite particles have a spherical shape, and the HA - with a flat
located on the edges of the functional groups, calculated the size of the main core of the HA. We
have took Mr = 1400 c.u.excluded 7.4% ash, 0.33% sulfur, 1.17% nitrogen (of 8.9%), whereas for
carbon, hydrogen and oxygen has to 91.1% Mr = 1,400 × 0,911 = 1,275 c.u. Let the average
formula (S5,3O1,9N4) m (Mr = 98m), then the formula is (S5,3O1,9N4)13 or S69O25N52. The carboxyl
groups of 5.00 mmol / g of HA or 5×1400 = 7mol / molof HA (S7O14N7). Phenolic groups 2.4 mmol
/ g or HA 2,4 × 1400 = 3.36 mol / mol HA (O3,36N3,36). The aromatic aldehyde group 1.44 mmol / g
of HA or 1.44 × 1400 = 2.0 mol / molof HA (S2O2N2). All in all functional groups will take
S9O19,36N12,36. Then will S60O5,64N39,64 (or S60O6N40) on the aromatic ring. Oxygen is carried to the
water in the hydrated inorganic moieties. S60N37 remains built on the basis of this nucleus with the
functional groups (Fig. 1).
Fig. 1. Structural formula HA Mr = 1400, without the inorganic part.
The size of such a molecule diagonally (maximum distance) is equal to 1.5 nm. Accordingly it is
possible to construct a model of the HA of large size.
Figure 2 shows the structural formula of 16 times the HA molecules.
Fig. 2. Structural formula HA Mr = 22400 c.u. without inorganic part
It can be seen (Fig. 2) of the functional groups that can not fit on the perimeter of the molecule and
therefore they will be located in the plane of the aromatic ring. The linear size of the maximum
cross section diagonally molecule is 5.95 nm. It is 4 times greater than that of molecules Mr = 1400
c.u. Geometric analysis suggests that Mg HA molecules is proportional to the square of the line (s)
in the maximum size of the section. Therefore Mr1 / Mr2 = (x1 / x2)2.
A plot of the molecular weight of the linear size of the molecule is shown in Figure 3.
250000
Мr HA
200000
150000
100000
molecular
size
50000
0
0
5
10
15
Fig. 3. Dependence of the molecular weight of HA from a linear molecule in the maximum size of
its section
The graph shows that the molecular weight of 200,000 c.u. HA is a linear size of 18 nm. We take
the maximum size of HA 8 nm in length (2000000). Let a particle of magnetite (dFe3O4 = 15nm) is
uniformly covered on all sides with polymer molecules of HA, the diameter of the resulting
particles is equal to twice the sum of the radius rFe3O4 and length HA molecule (x) D = 2 (x +
rFe3O4) = 2R = 2 (18 + 7, 5) = 51nm (wherein R- coated particle radius).
When filling in the form of a cubic volume of a single particle of magnetite coated with HA will
hold the volume of V = D3 = 0,132 × 10-15 sm3.To there in one centimeter cubic should be not
more than 7.53 × 1015 magnetic particles of magnetite (Fig. 4).
a)
b)
Fig. 4. a)form is a distance between the production of nanoparticles of magnetic sorbent taken into
account, b)-form is a filling elementary volume of magnetite particles coated with HA in the form
of a cube
With a radius of magnetite particles of 7.5 nm (diametr15 nm), its volume is equal to V = (4/3) πr 3
= 1788nm3 (1,788 × 10-18 sm3), then the total amount of magnetite in the centimeter cubic VΣFe3O4
= 7,53 × 1015 × 1,766 × 10-18 = 13,3 × 10-3 cm3. A weight at ρ = 5,2 g / sm3 is equal to 69 × 10-3
g or 69 mg. Magnetite concentration at a rate of 15 nm particles should not exceed 69 mg / cm3 and
69 g / liter. Thus, to obtain 1 g Fe3O4 can take 50 ml of the ferric chloride solution and pour into 20
ml of 5% ammonia solution. The concentration of the magnetite particles was 14.3 g / l, which is
4.8 times less than the derived criterion of possible adhesion of magnetite particles for Mr (HA) =
200000c.u. Thus, the chosen magnetite concentration in the solution which guarantees the absence
of interaction between neighboring magnetite particles to each other through the carboxyl groups of
the same HA molecule.
Methods of producing of polymer hybrid sorbents based on magnetically IPM magnetite
areknown [5-15]. The obtaining composite based on pre-synthesized IPMof magnetite and humic
acids is used in the synthesis of the polymeric hybrid magneticallysorbents. However, the proposed
method is characterized in that magnetically hybrid polymeric sorbents are prepared by template
synthesis. These sorbents are selective, i.e. "tuned" to a particular metal ion. A method for
producing is as follows: a pre-formed composite formalin waspoured, kept for 3 hours and heated
on a steam bath for 2 hours.The cooled solution wascontained by means of magnet in the beaker
and the resultant reaction liquid was removed by decantation. Formalin is necessary for crosslinking
of HA molecules interconnected by a polycondensation reaction by HA phenolic components.
Additional role of formalin is to bind the remaining ammonia in the preparation of IPM magnetite,
turning it into a methenamine. All obtained substances (ammonium chloride, formaldehyde,
methenamine)aresoluble in ethanol, so lees was washed by ethanolto eliminate mesirization of lees.
Further washing removes excess of ammonium chloride, formaldehyde and hexamine completely.
Furthermore we produce solvent change in the following sequence: isopropyl alcohol,
benzene, xylene. When changing of the solvent a residue remains in the suspended state, but can be
easily assembled by magnet. Replacing of the solvent is intended to produce the composite in a
particular environment in which to spend its a final dehydration. When the heating to 142°C the
polycondensation reaction is completed to crosslinked framing structureof composite. To continue
exchange reactionswith the composite, it is necessary to transfer it to water environment. We
produce this reverse migrating of solvents by benzene, isopropanol, ethanol and water. Then the
excess of HAwas poured to composite in order to part of free COOH groups and acid phenolic
groups sorbed HA were remained free, i.e. unconnected with composite.These COOH groups
subsequently were used for the sorption of metals in ion exchange. Testing has shown that the
addition of HA solution is more 65-70% formsthe excess of HA, which is not contacted with the
composite (sample to a magnetic field). Consequently, the amount of HA solution was added to
form the second layer should be 50% in capacity on a given ion sorbed. It is advisable to keep all
the calculations of Mr. equivalent amounts. We calculated the number of HA required to create a
2nd layer with Ni2+.
To complete the reaction, it is necessary to add an excess of 5-10% of the metal acetate salt
solution. At the time of addition of solutions of metal sorption simultaneously on the composite and
in the dissolved HA take place such, that a bondsare formedbetween acid residues of the HA and
the composite surface through a multivalent metal ion. Then we added m-PDA 2 based m\eq per 1
m\eq metal. Formed complex compound m-PDA with the metal ion. The solution was heated
during 4 hours at 85-900C. Part of the active groups of m-PDA include in the polycondensation
reaction with the aldehyde groups of GA and partially crosslinks the composite. For the final crosslinking of m-PDA with HA, it is necessary, to add the excess of formalin. Thus, there is a new
crosslinking layer. The amount of formalin was 0.5-5 ml, which is not critical. The resulting
mixture was heated to polycondensation crosslinking for 2 hours at 85-90°C. It should be noted that
the addition of formaldehyde with m-PDA lead to competition with HA and aromatic aldehydes
complete consumption of active groups (H) as formalin activity is higher than the activity of the
functional groups of HA. Such a sequence of a method for producing must be strictly observed.
The synthesis of the template polymer hybrid magnetically sorbent with Ni2+
2 g magnetite is sorbedby 0.912 g of HA. The resulting composite can bind 1.40 × 2 = 2.80 m-eq
Ni2+. 50% was 1.40 m-eq Ni2+, which may be connected to the initial HAwith capacity of Ni2+ 3,37
m-eq / g. Hence, it is necessary to add 1.40: 3.37 = 0.415 g HA in the form of ammonium humate.
Ni2 +, we need to add 4.20 m-eq (42.0 ml of 0.1N solution Ni(CH3COO)2 + 10% = 46.2 ml). By
composite primary layer of HA and 41.5 ml of a 1% solution of ammonium humate, m-PDA
solution of 46.2 mg (4.6 ml) after exposure + 1 ml of formalin. To investigate the possibility of
obtaining customized polymers carried out acid hydrolysis [16] 0.1n hydrochloric acid template
polymer hybrid magnetically sorbent. For this purpose, 5 g of a sample of filled in 50 ml of 0.1n
hydrochloric acid solution and heated at 500C for 30 minutes. The lees was filtered, then washed
several times with 0.1n hydrochloric acid and then several times with distilled water of chlorine
ions and dried at 120°C. Weigh of the obtained hybrid polymeric template configured magnetically
sorbent was placed in 100 ml flask filled binary mixture of equal volumes of 0.1n salt solution (50
ml of a 0.1n solution of Ni(CH3COO)2 + 50 ml of a 0.1n solution of Cu(CH3COO)2). Table 2
shows the sorption of customized template polymer hybrid magnetically sorbent
Table 2. Sorption of customized template polymer hybrid magnetically sorbent h-tuned
customized template
Metal is sorbed
Binary solution
-1
composite
mg-eq-g
mol-g-1-10-3
Fe3O4:HA:
Ni:m-PDА-h
Ni(CH3COO)2
Cu(CH3COO)2
0,23
1,01
0,16
0,51
These data show, that the resulting customized template polymer hybrid magnetically sorbent
is selective, asit is oriented on a particular (given) metal ion. There is negligible adsorption of
another metal, because of the surface of the composite has a functional group which can bind minor
amounts of non-oriented metals. Sorption activity of template configured composites are largely
determined by the proportion of humic acids in their composition, as humic acid except oxygencontaining functional groups are capable of reacting with metals, have a considerable porosity, so
the quantity and size of poresalso depends on sorption activity with respect to a every metal.
The analysis of the structure of template composites by IR-spectroscopyare carried out. IR
spectra of the obtained material (Fig. 5) have an intense band at 1530-1570 sm-1 (communication
C=O), 1360-1370sm-1 (C=O), 400-600sm-1 (Fe-O), 3400-3000sm-1 (O-H). The proof of
coordination sites on the surface of the sorbents are absorption in 600-800 sm-1, which belong to the
stretching vibrations in the carboxyl complexes. Additionally, characteristic carbonyl band of
carboxyl groups oscillations (ν = 1640-1740sm-1) is attenuated.
Fig. 5. IR spectra of substances: 1 - HA, 2 - Fe3O4-HA80-CA; 3 - Fe3O4-HA50-CA; 4 - Fe3O4HA20-CA.
At the same time in spectra bands appear according to symmetrical (ν = 1390-1400sm-1) and
antisymmetric (ν =1560-1590sm-1) fluctuations of carboxylate ion. Thus, humic acids, which are
polyanions in water solutions,included into the system as growth stabilizers of iron oxides of
nanoparticles interact electrostatically with a positively charged nanoparticles of iron oxide (III).
This interaction leads to the stabilization of colloidal systems. The spectrum of possible complexes
with iron oxides of HA wide and, of course, not limited to the forms of the components and the type
of interaction. Functional groups of HA occupy all available for the coordination of space on the
surface of nanoparticles, i.e. smaller nanoparticles "enveloped" by polyanion absorbed "dendritic"
structure of HA.
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Виноградов Виктор Владимирович – кандидат химических наук, с.н.с. лаборатории
материаловедения ИХ и ХТ НАН КР, Проспект Чуй 256 т. 64-19-33.
Касымова Эльвира Джапашевна - кандидат химических наук, доцент, с.н.с. лаборатории
биофизической химии ИХ и ХТ НАН КР, Проспект Чуй, 256, т. 64-19-33.