Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents
The composition and structure of initial and modified lignocellulose materials have been investigated by ¹³C NMR spectroscopy. Changes in functional structure and composition of the samples have been found to arise due to modifying as a result of chemical transformations and hemicelluloses removing....
Збережено в:
| Опубліковано в: : | Хімія, фізика та технологія поверхні |
|---|---|
| Дата: | 2011 |
| Автори: | , |
| Формат: | Стаття |
| Мова: | Англійська |
| Опубліковано: |
Інститут хімії поверхні ім. О.О. Чуйка НАН України
2011
|
| Онлайн доступ: | https://nasplib.isofts.kiev.ua/handle/123456789/29044 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents / M.T. Kartel, A.A. Nikolaichuk // Хімія, фізика та технологія поверхні. — 2011. — Т. 2, № 1. — С. 81-85. — Бібліогр.: 7 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860214993711005696 |
|---|---|
| author | Kartel, M.T. Nikolaichuk, A.A. |
| author_facet | Kartel, M.T. Nikolaichuk, A.A. |
| citation_txt | Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents / M.T. Kartel, A.A. Nikolaichuk // Хімія, фізика та технологія поверхні. — 2011. — Т. 2, № 1. — С. 81-85. — Бібліогр.: 7 назв. — англ. |
| collection | DSpace DC |
| container_title | Хімія, фізика та технологія поверхні |
| description | The composition and structure of initial and modified lignocellulose materials have been investigated by ¹³C NMR spectroscopy. Changes in functional structure and composition of the samples have been found to arise due to modifying as a result of chemical transformations and hemicelluloses removing. Sorption properties of lignocellulose composites have been studied in relation to heavy metals. They have been found to depend on changes in the composition and functional structure of the materials.
Методом ¹³C ЯМР-спектроскопії досліджено склад і структуру вихідних і модифікованих лігноцелюлозних матеріалів, а також їх сорбційні властивості. Встановлена залежність сорбційних властивостей лігноцелюлозних композитів по відношенню до важких металів від змін у функціональному складі й структурі лігноцелюлозних композитів внаслідок їхнього перетворення й видалення геміцелюлози в результаті кислотнолужного модифікування.
Методом ¹³C ЯМР-спектроскопии исследован состав и структура исходных и модифицированных лигноцеллюлозных материалов. Изучены сорбционные свойства лигноцеллюлозных материалов, и установлена зависимость сорбционных свойств их композитов по отношению к тяжелым металлам от изменений в функциональном составе и структуре лигноцеллюлозных композитов, вызванных их превращением и удалением гемицеллюлозы при кислотно-щелочном модифицировании.
|
| first_indexed | 2025-12-07T18:15:40Z |
| format | Article |
| fulltext |
Хімія, фізика та технологія поверхні. 2011. Т. 2. № 1. С. 81–85
_____________________________________________________________________________________________
* corresponding author nikar@kartel.kiev.ua
ХФТП 2011. Т. 2. № 1 81
UDC 544.723
COMPARATIVE 13C NMR SPECTROSCOPY
OF LIGNOCELLULOSE SORBENTS
M.T. Kartel*, A.A. Nikolaichuk
Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine
17 General Naumov Street, Kyiv 03164, Ukraine
The composition and structure of initial and modified lignocellulose materials have been inves-
tigated by 13C NMR spectroscopy. Changes in functional structure and composition of the samples
have been found to arise due to modifying as a result of chemical transformations and hemicellu-
loses removing. Sorption properties of lignocellulose composites have been studied in relation to
heavy metals. They have been found to depend on changes in the composition and functional struc-
ture of the materials.
INTRODUCTION
When separating or purifying vegetative raw
materials it is impossible to produce without inten-
sive chemical treatment the samples of cellulose
containing no lignin, or cellulose free lignin prepa-
rations [1]. Meanwhile, dividing vegetative fabrics
into separate high-molecular components is not
necessary for manufacture of useful related materi-
als. The products obtained from the waste of vegeta-
tive biomass, even without preliminary dividing into
components, can have new properties essentially
distinctive from components. Besides, use of the
whole biomass in a uniform production is undoubt-
edly technologically rational and economic.
EXPERIMENTAL
The objects under research were different
kind lignocelluloses complexes of vegetative raw
materials (hazelnut shell, corncob, and cacao
husks) and the materials obtained due to their
acid-alkaline modifying by the method described
in the patent [2]; for comparison the lignin-
containing medical preparation “Polyphepan” [3]
has been selected as the closest analogue of in-
vestigated materials.
To determine the composition of lignocellu-
loses complexes 13C solid-state spectra of Cross-
Polarization Magic-Angle Spinning Nuclear Mag-
netic Resonance (CP MAS NMR) of initial and
modified powdered samples of investigated mate-
rials have been recorded and analyzed. The spectra
were registered by a Bruker AVANCE 400 radio-
spectrometer in a pulse mode of accumulation
with working frequency of 100.3 MHz and cross-
polarization on frequency of 400.13 MHz (Н1);
the interval between pulses was 4 s. The rotation
speed of the samples under the magic corner was
of 12 kHz. The values of chemical shifts (δ) of
the signals from carbon atoms in 13
С nuclear
magnetic resonance spectra were defined con-
cerning standard ТМS (δ = 0 ppm).
The study on selectivity and sorption ca-
pacities of the chosen materials was carried
out under static conditions with use of salt so-
lutions of heavy metals (lead, cadmium,
nickel, copper, strontium) containing different
concentrations (5–100 mg/l) of metal ions. Initial
and equilibrium concentrations of metals in solu-
tions were defined by a Selma KASS-120.1
atomic-absorption spectrophotometer.
RESULTS AND DISCUSSION
It is known [4] that signals of various car-
bon atoms in both natural and biosynthetic
polymers, with few exceptions, are not over-
lapped and consequently are characteristic, so
allowing to identify separate types of struc-
tural units in such materials. In the 13
С NMR
spectra of natural and biosynthetic lignins in a
lignocellulose complex, four basic ranges of δ are
allocated [4, 5]:
– 5–45 ppm – signals of aliphatic carbon
atoms, non-bonded with oxygen atoms
( >CH–, –СН2–, and –СН3 groups);
– 55–90 ppm – signals of aliphatic carbon at-
oms bonded with oxygen atoms;
– 100–160 ppm – signals of carbon atoms in
sp2-hybridization [6] as a part of aromatic and
olefine structures;
M.T. Kartel, A.A. Nikolaichuk
_____________________________________________________________________________________________
82 ХФТП 2011. Т. 2. № 1
– 160–180 ppm – intensive signals of γ-carbon
atoms entering ester or di-γ-lactone group-
ings, and also carboxyl groups.
The analysis of the spectra obtained
shows that the initial and modified samples of
wood nut shell, corn cabbage stumps and cacao
vela contain signals with the following δ value:
20–40 ppm from –СН3 and –СН2- groups of
hemicelluloses; 60 ppm from methoxy
groups of lignin; 65 ppm from carbon atoms
С-6; 70–75 ppm from atoms С-2,3,5 of cellu-
lose; 80–90 ppm from atoms С-4 of cellulose;
120–160 ppm from aromatic carbon atoms of lig-
nin; 175 ppm from carboxyl carbon atoms of
hemicelluloses.
13C CP MAS NMR spectra of the modified
samples differ from those of predecessors by es-
sential reduction signal intensity of –СН3 and
=СН2 groups of hemicelluloses (20–40 ppm),
and also alkyl (30–33 ppm) and carboxyl
(170–175 ppm) groups of hemicelluloses.
It is also seen from Fig. 1a-c that signals of
hemicelluloses groups disappear, and intensity of
other lines (groups of cellulose and lignin) in-
creases. This testifies to structural changes in lig-
nocellulose skeleton due to its modifying.
The investigated samples differ from that of
Polyphepan (Fig. 1d) intensity of signals in areas
of 60 and 120–160 ppm that specifies a higher
content of lignin in the preparation than those in
investigated ones. It is natural, as Polyphepan is
produced from wood which is richer by lignin
vegetative raw material.
Comparing 13C NMR spectra of investigated
samples with literary data [5], it is possible to
assign the signals observed in the field of 5–45
ppm to carbon atoms in groups > CH–, –СН2–,
–СН3, non-bonded with atoms of oxygen, in lat-
eral aliphatic chains between aromatic rings of
lignin. The total number and position of signals
in spectra of all the samples coincide. In the
spectra of investigated lignocellulose complexes,
there are signals with δ = 53.5 and 53.8 ppm tes-
tified to presence of coumaran and pinoresinol
fragments in macromolecules. In investigated
lignocellulose materials, there are also two accu-
rate resonant signals of ОСН3-groups: δ = 55.7
and 55.9 ppm. It is known [4] that a signal with
δ =55.6 ppm is caused by methoxyl group in
ortho-position, and a signal of 56.0 ppm presents
carbon atoms in methoxyl groups of syringyl
rings.
a
b
c
d
Fig. 1. 13
С NMR spectra of samples: hazelnut shell (a), corn-
cob (b), cacao husks (c), and preparation Polyphepan
(d); 1 – initial, 2 – modified
Comparative 13C NMR Spectroscopy of Lignocellulose Sorbents
_____________________________________________________________________________________________
ХФТП 2011. Т. 2. № 1 83
As it was already mentioned, the area of
100–160 ppm of a spectrum contains resonant
signals of carbon atoms with sp2-hybridizations of
valent electrons [6] involved in aromatic and ole-
fine structures. In this area, four intervals are con-
ditionally allocated [1]:
– 100–117 ppm, where signals of tertiary car-
bon atoms including those of C-atoms in or-
tho-position with oxygen function (С-2 and
С-5 in not condensed fragments) are regis-
tered;
– 117–125 ppm, where signals of C-Har (С-2/С-
5 - structures replaced in position С-1 of
aromatic ring) are observed;
– 125–142 ppm, where the signals belong to
aromatic quaternary carbon atoms, mainly
С-1 and С-5;
– 142–160 ppm, where the signals caused by
presence of esterified carbon atoms of aro-
matic ring are registered.
In our case, in spectra of 13C СР MAS NMR,
signals of carbon atoms of (С-2/С-6) in the range
δ = 103–107 ppm are observed caused by pres-
ence of syringyl aromatic rings, and this is the
main difference of spectra for lignin of investi-
gated samples (guaiacyl-syringyl type) from those
of lignin of coniferous species [1].
The signals shown in investigated samples
with δ = 102–104 ppm correspond to
non-replaced carbon atoms С-2 and С-6 in syrin-
gyl fragments of preparations, δ in a range of
150–160 ppm – with С-З/С-5 atoms bound with
methoxy groups. A signal at δ = 119 ppm speci-
fies in presence of guaiacyl fragments (С-6).
Peaks with values δ = 131.4-131.5 ppm (С-2–С-6
atoms in N-units) are characteristic of
n-cumarone structures [1, 5].
In the range of 160–180 ppm there are peaks
of γ-carbon atoms entering ester and di-γ-lactone
groups and those of carboxyl groups. As in this
range there are no signals of other carbon atoms,
there is a basic possibility of reliable definition of
various type structural fragments carboxyl car-
bon, and signals with δ > 170 ppm confirm pres-
ence such groups in preparations. A group of
three close located signals in the field of δ =
171.0–173.2 ppm is caused, probably, by the
presence of carboxyl carbon atoms in 3-alkyl-aril-
ether structural elements [4].
So, the results of the analysis of nuclear mag-
netic resonance 13C СР MAS spectra on chemical
shifts of resonant signals (Table) testify that lig-
nin macromolecules, which are a part of ligno-
celluloses complexes of investigated samples, are
built by structural units of guaiacyl, syringyl, and
n-cumarone types.
Table. Chemical shifts of resonant signals of 13C
NMR spectra of lignocelluloses complexes of
modified vegetative raw materials (ppm)
Groups Cacao
husks
Hazelnut
shell
Corncob Poly-
phepan
–СН3
14.6;
19; 24
29 24.5 18; 23
–СН2- 30; 33; 36 33 33 33; 37; 45
Сβ in β5 and
(β-β)
54 53.8 53.5 53.8
Ar-OCH3 G and
S rings
56 56 55.9 55.7
Сγ(β-5) and
(β-О-4) G ring
62; 64 63; 65 66; 68 62; 65
Сα(β-О-4) G and
S rings
72; 74 72; 74 76; 78 72; 74
Сβ – 83; 88 87 84; 88
Calif.-3 – – 92 –
С-2 and С-6 in
S and S’
100.9;
104.9
104 108 105
С-2 G ring 119 118 119 114
С-1 in Н – 122 – 123
Сα and Сβ in
coniferil-aldehyde
structures and (or)
С-2 and С-6 Н
– – – 130.9
С-2 and С-6 Н, Н’ 131 132.9 131 –
C-4 S S’ – – – –
C-4 G’
non-esterified
144.4 144 – 146
C-3 G
non-esterified
– – – –
C-3 G’
esterified
– – – –
C-3 and С-5 S’
esterified
154.5 152 151 151
С=О
COOR in β-О-4
– 171 – –
С=О
COOН in β-О-4
172 – – –
С=О
COOН in β-5
174 – – –
Dependences of sorption properties on the
composition and structure of multi-component
vegetative materials were found. It is revealed
that cellulose and lignin joint into biopolymer
complexes in non-treated (initial) materials show
weak sorption capability in relation to heavy
metal ions whereas modified lignocellulose mate-
rials possess quite high absorption characteristics.
M.T. Kartel, A.A. Nikolaichuk
_____________________________________________________________________________________________
84 ХФТП 2011. Т. 2. № 1
Какавелла
0
10
20
30
40
50
60
70
80
90
100
Cd Cu Ni Sr Pb
%
a
0
10
20
30
40
50
60
70
80
90
100
Cd Cu Ni Sr Pb
%
b
0
10
20
30
40
50
60
70
80
90
100
Cd Cu Ni Sr Pb
%
c
0
10
20
30
40
50
60
70
80
90
100
Cd Cu Ni Sr Pb
%
d
Fig. 2. Diagrams of adsorption of heavy metals
from solutions by vegetative biosorbents: (a)
cacao husks, (b) hazelnut shell, (c) corncob, (d)
Polyphepan
As an example in Fig. 2 the diagrams of effi-
ciency of heavy metal ions extraction from model
aqueous solutions of Cu, Pb, Sr, Ni, Cd salts (at
initial concentration of metals in a solution 1×10-3
mol/l) are resulted. They demonstrate that the
modified adsorbents based on vegetative waste
have high indices of extraction of heavy metal
ions from aqueous solutions. Sorption properties
of initial vegetative raw materials in relation to
heavy metals ions are rather close to those of
preparation Polyphepan; the modified materials
show, as a whole higher sorption capabilities.
A comparison of the modified and initial samples
shows that the extraction level of metals from
solutions becomes more than 2 times greater. It is
obvious also that the medical preparation Poly-
phepan considerably concedes to the materials
obtained in extraction degrees of such metals as
Cu, Ni, Sr.
From a content ratio of lignin, cellulose, and
hemicelluloses (intensities of peaks of the corre-
sponding groups) a dependence row of adsorption
capability on the material composition is con-
structed. For example, for Cu2+-ions adsorption
the capability increases as follows:
Cacao husks > Hazelnut shell > Corncob.
CONCLUSIONS
Comparison of the results obtained on ad-
sorption of heavy metals with data of 13
С NMR
spectroscopy, taking into account structural-
sorption characteristics of the materials obtained
[7], shows that sorptive properties of the latter are
defined not only by volume of sorption pores but
also essentially depend on the structure of ligno-
celluloses complexes, chemical bonds between
their components, and nature of metals.
The results obtained testify that acid-alkaline
modifying natural raw materials allows us to re-
move hemicelluloses from vegetative raw materi-
als of various origins and to prepare new sorption
materials with higher availability of functional
groups to heavy metal ions. As the materials ob-
tained show a definite selectivity in relation to
ions of some heavy metals, it is possible to rec-
ommend usage of such biosorbents for deep ex-
traction of these elements from industrial solu-
tions and sewage waters.
ACKNOWLEDGEMENT
Authors bring profound gratitude to Dr. V.V.
Trachevsky (Technical Centre, Kurdyumov Insti-
Comparative 13C NMR Spectroscopy of Lignocellulose Sorbents
_____________________________________________________________________________________________
ХФТП 2011. Т. 2. № 1 85
tute of Physics of Metals, NAS of Ukraine) and
Dr. V.S. Kouts (Chuiko Institute of Surface
Chemistry, NAS of Ukraine) for their help in ob-
taining and interpretation of NMR-spectra of lig-
nocellulose materials.
REFERENCES
1. Fernandez-Bolanos J., Felizon B., Herediat A.,
et al. Characterization of the lignin obtained
by alkaline delignification and of the cellu-
lose residue from steam-exploded olive
stones // Bioresour. Technol. – 1999. – V. 68,
N 2. – P. 121–132.
2. Pat. 76835 Ukraine, Int. Cl. A61K 36/87
Method of obtaining lignin-containing
enterosorbents (variants) / V.O. Denisovych,
A.A. Nikolaychuk, L.A. Kupchik, M.T. Kartel –
Appl. No. 20040907527, Filed 15.09.2004,
Publ. 15.09.2006. – 8 p. (in Ukrainian).
3. Semenkova G.G., Provotorov V.M., Ve-
likaia O.V. The correction of the imbalance in
the proteinase-inhibitor system of patients
with protracted pneumonia with the entero-
sorbent polifepan // Klinicheskaya medi-
tsina. – 1995. – V. 73, N 1. – Р. 48–50. (in
Russian).
4. Karmanov A.P. Monakov Yu.B. The structure
of lignin macromolecules // Polym. Sci. B. –
1996. – V 38, N 9–10. – Р. 384–394.
5. Li M.-F., Fan Y.-M., Xu F. et al. Cold so-
dium hydroxide/urea based pretreatment of
bamboo for bioethanol production: Charac-
terization of the cellulose rich fraction. //
Ind. Crops Prod. – 2010. – V. 32, N 3. –
P. 551–559.
6. Zhao H., Kwak J.H., Zhang Z.C. et al., Study-
ing cellulose fiber structure by SEM, XRD,
NMR and acid hydrolysis // Carbohydr. Po-
lym. – 2007. – V. 68, N 2. – P. 235–241.
7. Nikolaichuk A.A., Kartel N.T., Kupchik L.A.,
Denisovich V.A. Synthesis and properties of
biosorbents obtained from cellulose-lignin
vegetative raw materials – wastes of agricul-
tural complex // Sorbcionnye i hroma-
tograficheskie processy. – 2007. – V. 1,
N 3. – P. 489–498. (in Russian).
Received 05.02.2011, accepted 18.02.2011
Порівняльне дослідження лігноцелюлозних сорбентів
методом 13
С ЯМР-спектроскопії
M.T. Картель, A.A. Ніколайчук
Інститут хімії поверхні ім. О.О. Чуйка Національної академії наук України
вул. Генерала Наумова 17, Київ 03164, Україна, nikar@kartel.kiev.ua
Методом 13C ЯМР-спектроскопії досліджено склад і структуру вихідних і модифікованих лігноцелюлозних
матеріалів, а також їх сорбційні властивості. Встановлена залежність сорбційних властивостей лігноце-
люлозних композитів по відношенню до важких металів від змін у функціональному складі й структурі ліг-
ноцелюлозних композитів внаслідок їхнього перетворення й видалення геміцелюлози в результаті кислотно-
лужного модифікування.
Сравнительное исследование лигноцеллюлозных сорбентов
методом 13
С ЯМР-спектроскопии
Н.Т. Картель, A.A. Николайчук
Институт химии поверхности им. А.А. Чуйко Национальной академии наук Украины
ул. Генерала Наумова 17, Киев 03164, Украина, nikar@kartel.kiev.ua
Методом 13C ЯМР-спектроскопии исследован состав и структура исходных и модифицированных лигноцел-
люлозных материалов. Изучены сорбционные свойства лигноцеллюлозных материалов, и установлена зави-
симость сорбционных свойств их композитов по отношению к тяжелым металлам от изменений в функ-
циональном составе и структуре лигноцеллюлозных композитов, вызванных их превращением и удалением
гемицеллюлозы при кислотно-щелочном модифицировании.
|
| id | nasplib_isofts_kiev_ua-123456789-29044 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 2079-1704 |
| language | English |
| last_indexed | 2025-12-07T18:15:40Z |
| publishDate | 2011 |
| publisher | Інститут хімії поверхні ім. О.О. Чуйка НАН України |
| record_format | dspace |
| spelling | Kartel, M.T. Nikolaichuk, A.A. 2011-11-29T18:29:30Z 2011-11-29T18:29:30Z 2011 Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents / M.T. Kartel, A.A. Nikolaichuk // Хімія, фізика та технологія поверхні. — 2011. — Т. 2, № 1. — С. 81-85. — Бібліогр.: 7 назв. — англ. 2079-1704 https://nasplib.isofts.kiev.ua/handle/123456789/29044 544.723 The composition and structure of initial and modified lignocellulose materials have been investigated by ¹³C NMR spectroscopy. Changes in functional structure and composition of the samples have been found to arise due to modifying as a result of chemical transformations and hemicelluloses removing. Sorption properties of lignocellulose composites have been studied in relation to heavy metals. They have been found to depend on changes in the composition and functional structure of the materials. Методом ¹³C ЯМР-спектроскопії досліджено склад і структуру вихідних і модифікованих лігноцелюлозних матеріалів, а також їх сорбційні властивості. Встановлена залежність сорбційних властивостей лігноцелюлозних композитів по відношенню до важких металів від змін у функціональному складі й структурі лігноцелюлозних композитів внаслідок їхнього перетворення й видалення геміцелюлози в результаті кислотнолужного модифікування. Методом ¹³C ЯМР-спектроскопии исследован состав и структура исходных и модифицированных лигноцеллюлозных материалов. Изучены сорбционные свойства лигноцеллюлозных материалов, и установлена зависимость сорбционных свойств их композитов по отношению к тяжелым металлам от изменений в функциональном составе и структуре лигноцеллюлозных композитов, вызванных их превращением и удалением гемицеллюлозы при кислотно-щелочном модифицировании. Authors bring profound gratitude to Dr. V.V. Trachevsky (Technical Centre, Kurdyumov Institute of Physics of Metals, NAS of Ukraine) and Dr. V.S. Kouts (Chuiko Institute of Surface Chemistry, NAS of Ukraine) for their help in obtaining and interpretation of NMR-spectra of lignocellulose materials. en Інститут хімії поверхні ім. О.О. Чуйка НАН України Хімія, фізика та технологія поверхні Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents Порівняльне дослідження лігноцелюлозних сорбентів методом ¹³С ЯМР-спектроскопії Сравнительное исследование лигноцеллюлозных сорбентов методом ¹³С ЯМР-спектроскопии Article published earlier |
| spellingShingle | Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents Kartel, M.T. Nikolaichuk, A.A. |
| title | Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents |
| title_alt | Порівняльне дослідження лігноцелюлозних сорбентів методом ¹³С ЯМР-спектроскопії Сравнительное исследование лигноцеллюлозных сорбентов методом ¹³С ЯМР-спектроскопии |
| title_full | Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents |
| title_fullStr | Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents |
| title_full_unstemmed | Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents |
| title_short | Comparative ¹³C NMR Spectroscopy of Lignocellulose Sorbents |
| title_sort | comparative ¹³c nmr spectroscopy of lignocellulose sorbents |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/29044 |
| work_keys_str_mv | AT kartelmt comparative13cnmrspectroscopyoflignocellulosesorbents AT nikolaichukaa comparative13cnmrspectroscopyoflignocellulosesorbents AT kartelmt porívnâlʹnedoslídžennâlígnocelûloznihsorbentívmetodom13sâmrspektroskopíí AT nikolaichukaa porívnâlʹnedoslídžennâlígnocelûloznihsorbentívmetodom13sâmrspektroskopíí AT kartelmt sravnitelʹnoeissledovanielignocellûloznyhsorbentovmetodom13sâmrspektroskopii AT nikolaichukaa sravnitelʹnoeissledovanielignocellûloznyhsorbentovmetodom13sâmrspektroskopii |