• AR C H IV E_S,
FISHERIES RESEARCH BOARD OF CANADA
Translation Series No. 2004
Methods of increasing the quality of sodium alginate
by N. A. Gernet and G. V. Vinogradova
Original title: Puti povysheniya kachestva al'ginata natriya
From:
Trudy Polyarnyi Nauchno-Issledovatel'skii i Proektnii
Institut Morskogo Rybnogo Khozyaistva i Okeanografii
(PINRO) (Proceedings of the Polar Research Institute
of Marine Fisheries and Oceanography), 13 : 111-113, 1970
Translated by the Translation Bureau(TS)
Foreign Languages Division
Mepartment of the Secretary of State of Canada
Fisheries Research Board of Canada
Vancouver Laboratory
Vancouver, B. C.
5 pages typescript
c.egeodii
,
"="
'
ow—
•
SECRÉTARIAT D'ÉTAT
BUREAU DES TRADUCTIONS
DEPARTMENT OF THE SECRETARY OF STATE
TRANSLATION BUREAU
FOREIGN LANGUAGES
DIVISION
DIVISION DES LANGUES
ÉTRANGÈRES
CANADA
INTO - EN
TRANSLATED FROM - TRADUCTION DE
ENGLISH
RUSSIAN
AUTHOR - AUTEUR
N. A. Gernet and G. V. Vinogradova
TITLE IN ENGLISH - TITRE ANGLAIS
Methods for improving the quality of sodium alginate.
Title in foreign language (transliterate foreign characters)
Puti povysheniya kachestva aliginata natriya.
RV;RENCE IN FOREIGN 1ANGUAleE (NAME OF BOOK OR PUBLICATION) IN FULL. TRANSLITERATE FOREIGN CHAFACTERS.
REFERENCE EN LANGUE ETRANGERE (NOM DU LIVRE OU PUBLICATION). AU COMPLET. TRANSCRIRE EN CARACTERES PHONÉTIQUES.
Trudy Polyarnogo Nauchno-issledovaterskogo i proektnogo Instituta Morskogo
Rybnogo Khozyaistva i Okeanografii (PIERO)
REFERENCE IN ENGLISH - RÉFÉRENCE EN ANGLAIS
Transactions of the Polar Research Institute of Marine Fisheries and Oceanography
(PIERO).
: PUBLISH ER - ÉDITEUR
DATE OF PUBLICATION
DATE DE PUBLICATION
-
PAGE,NUMBERS IN ORIGINAL
NUMÉROS DES-PAGES DANS
L'ORIGINAL
PIENRO
YEI1R
ANNEE
PLACE OF PUBLICATION
LIEU DE PUBLICATION
VOLUME
ISSUE NO.
NUM 'ÉRO
USSR
1970
REQUEeTING DEPA RTMENT
MINISTERE ■ CLIENT
BRANCH OR DIVISION
DIRECTION OU DIVISION
PERSON ItEQUESTING
DEMANDE PAR
YOUR NUMBER
VOTRE DOSSIER N O
DATE OF R EQUEST
DATE DE LA DEMANDE
Environment (F.R.B.)
Vancouver Laborat ory
Dr.I.Whyte
Vancouver, B.C.
111 - 113
NUMBER OF TYPED PAGES •
NOMBRE DE PAG.ES
DACTYLOGRAPHIEES
5
13
TRANSLATION BUREAU NO.
NOTRE DOSSIER NO
1032
TRANSLATOR (INITIALS)
TRADUCTEUR (INITIALES)
DATE C.OMPL ETE D
ACHEVE LE
T. S.
JAN 1 8 1972
769-18-14
UNEDITED TRANSLATION
October 28, 1971
For infonnalion only
TRADUCTION NON REVISEE
Information seulement
3015.200-10.13 (REV. 2/6IN
SECRÉTARIAT D'ÉTAT
.,MŒPARTMENTOFTHESECRETARYOFSTATE
TRANSLATION BUREAU
BUREAU DES TRADUCTIONS
FOREIGN LANGUAGES DIVISION
DIVISION DES LANGUES ÉTRANGÈRES
CANADA
DEPARTMENT
MINISTERE
CLIENTS NO.
No DU CLIENT
769-18-14
Environment
CITY
DIVISION/BRANCH
DIVISION/DIRECTION
F.R.B.
Vancuuver Laboratory
BUREAU NO.
N° DU BUREAU
LANGUAGE
LANGUE
TRANSLATOR (INITIALS)
TRADUCTEUR (INITIALES)
1032
Russian
T. S.
VILLE
Vancouver
DATE
JAN 1 8 1972
!
UNEDITED TRANSLATION
UDC 678.554
For inforrna'.ion only
TRADUCTION NON Rï.:VISEE
Puti povysheniya kachestva al 'ginata natriya.
Information seulement
Published in: Trudy PINRO, No.XIII, pp.111 - 113.
By: N. A. Gernet and . G. V. Vinogradova
Marine Algae Laboratory
Methods for
improving the quality of sodium alginate.
111
Sodium alginate, because of its capacity to produce viscous colloidal
solutions, is very valuable in different branches of industry.
The de-
manda on alginate are varied, depending on where and for what 'purpose it
is used. For instance, the "Protan" Company in Norway produces 110 alginates of different naines, all of which have a different viscosity and
pUrity of solutions.
•
A high quality alginate should be well Purified, be light in • .
colour, have a high molecular weight and a high viscosity.
The Arkhangel' sk algae processing plant produces a sodium alginate
brand. calLed "Technical", which is used primarily in the textile industry.
Its limited use is due to its dark colour and low qualitative indices.
The initial treatment of the algae at the Arkhangel'sk algae processing •
SOS-200-10-31
2
plant is done in a reactor: due to the way the latter is deeigned the
wash water cannot be drained and, therefOre, furthertreatment of the
algae is done in the same solution. .Inasmuch as the algae are not
cleaned of the water-solubles, the solutions of sodium alginate are
dark and viscous, whieh makes their further cleaning difficult.
The cleaning of alginate solutions is done in the plant by
precipitation and by filtreion using a vacuum filter.
This type of
cleaning does not entirely clean the solution of suspended particleè
of cellulose; the sodium alginate solutions still contain a certain
amount of insoluble agents to the detriment of the appearance (colour)
of the final alginate solution.
Moreover, a certain amount of sulphuric
acid (0.2 - 0,4 g/kg) remainsin the algin after . waShing and this latér
will lower the quality of the alginate.
The conversion of algin into sodium alginate at the plant is
done by the addition of sodium bicarbonate;
the finished alginate has
a wide range of alkalinity (pH.6 - 11.6);-this affects the viscosity of
the alginate. The alginate is dried in roller dryers at a temperature
o
o
of +120 - +140 C. This high drying temperature lowers its quality.
In 1967 a project was conducted to establish the effect of . the
fo37lowingoon the viscosity of the finished product:
a)
The initial treatment of the algae;
h) The washing of the algin;
- ,e)
The alkalinity of the alginate solutions.
For this project we used taw material (Laminaria) Which had been
procured during 1966 - 1967.
3
Properties of the algae:
moisture content:
ash content:
112
24 - 26%
22.5%
alginic acid content:
30.0%-
Initial treatment of the algae.
Before they were dissolved the algae were treated using one of
.the following methods:
1. washed twice in cold water
2. washed in 1.0 - 0.5% sulphuric acid solution followed by a
•
water Wash
•
3. washed .in 1.0 .r 0.5% formaldehyde solution.
After the initial treatment the ash content of the algae dropped
from 24 - 26% to 10 - 13%; they were washed free of.sand.andmud.
The
treated algae were dissolved in a soda solution at a temperature of 200 25° C.
It is worth noting that after the initial treatment of the algae
the solutions of sodium alginate were much lighter in colour than those
which were not treated.
Effect on the degree of purity of the algin wash.
Algin was istklated from the solution in the usual manner. It
was then washed in water. The quality of the wash was checked according
to its pH factor, using the LPU-0.1 (laboratory pH-meter).
An alginate
was prepared from the algin which had been washed to different degrees .
.of puritY and the viscosity of 1%. alginate solution , was measured in an
giligeelrizoosity-meter le a temperature of 20° C. (Table 1).
_
•
•
••••
•
4
Table 1.
Resultant viscosity of the alginate solution.
Sodium alginate
..viscositste
Test No.
Alen pH
PH
1
1,55
1.82
2.15
2.37
1.6
1.9.
2.25
2.5
1.7
7.1
7.0
6.8
1.03 •
7.6
7.5
7.25
7.9
7.25
2
3
-
2.05
2.23
2.55
7.9
6.7.
6.8
•
.
6.53
9.51
10.75
16.20
7.64
. 12.37
21.52
' 22.5
8.51
.
10.99
17.48
22.5
As can be seen in Table.1, the quality of the algin•wash affects
•
the viscosi-ty of the finished alginate. The highest alginate viscosity
is obtained from àlgin washed to pH 2.3 - 2.5.
•
Effect of pH of the sodium alginate solution..
.
A sodium alginate
in:, a solution of varying pH was prepared frOm
the algin produced in the usual manner and washed •io a specific pH, the,'
viaciosity of the resulting . 1%. alginate solution was then determined.
(Table 2).
Table 2. ,
113
Visoosity of the 1% solution.
pH of the washed algin
2.25
It
tt
2 .37
It
tt
tt
pH
Sodium Alginate
Viscosity of 1% solution
6.6
6.77
18.5
19.7
7.55 .
7,73
9.1
6.2
16.04 .
15.2
13.5
18.3
7.03
7.72
16.2
15.2'
9.9
11.76
5
As can be seen from the above data, the sodium alginate solutions
reach maximum viscosity at pH 6.5 — 7.5. ,It is necessary therefore to
prepare alginates with such a pH.
'
It is customary at the Arkhangel'sk algae processing plant to
use sodium bicarbonate for the preparation of sodium alginate. The
results of experiments have shown that when the alginate is prepared with
bicarbonate of soda, the pH value of the finished alginate cannot be foreseen because the pH is lowered when carbon dioxide is formed during the
neutralization period and the pH of the finished sodium alginate solution
rises as the carbon dioxide escapes during the drying period.
To prepare sodium alginate we used a sodium hydroxide solution.
The use of sodium hydroxide does not deteriorate the colour of the alginate
and makes it possible to prepare an alginate with a specific pH value,
since.in this case the pH of the solutions before they are dried, as well
as that of the finished alginate l is practically constant. The alginate
produced under these conditions has a high molecular weient_and a high .
viscosity.
Conclusions.
•
1.
•
To obtain an alginate With a high molecular weight and high
viscosity it is necessary to treat the algae using one of the following
methods:
a) wash twice in water
b)
treat with 1.0 0.5% sulphuric adid solution followed.
by Washing in water .
c) - treat with 1.0 — 0.5% formaldehyde solution.
2. Wash the algin to pH 2.3 . — 2.5
.
-
3. Use a sodium hydroxide solution to prepae the alginate ;
the pH of the alginate solution Should not exceed 7.5. .
.