1070-4272/05/7808-1288 + 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 8, 2005, pp. 1288!1293. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 8, 2005,
Original Russian Text Copyright + 2005 by Pisarska, Dylevski.
AND CORROSION PROTECTION OF METALS
Analysis of Preparation Conditions of H
from Sodium Sulfate Solutions by Electrodialysis
B. Pisarska and R. Dylevski
Institute of Inorganic Chemistry, Gliwice, Poland
Silesian Technical University, Gliwice, Poland
Received February 7, 2002
Abstract-Preparation of sulfuric acid and sodium hydroxide from solutions containing sodium sulfate was
studied by the electrodialysis method in a three-chamber (?three-compartment) electrodialyzer equipped with
two membranes, an anion-exchange membrane AESD-2a and a cation-exchange membrane Nafion 427.
Manufacture of some fatty acids [1, 2], synthetic
fibers, and inorganic and organic compounds  and
integrated processing of worked-out lead batteries 
yield spent solutions containing sodium sulfate, which
are considered nontoxic and are discharged as waste-
water. In most cases, sodium sulfate is formed in spent
solutions when sulfuric acid and sodium hydroxide
are used as technological solutions. Hence follows
that it would be possible to solve the ecological prob-
lems associated with the formation and discharge of
spent solutions containing sodium sulfate if there ex-
isted an effective and cost-efficient method for their
processing to obtain sulfuric acid and sodium hy-
droxide. This would enable development of integrated
(conjugated) closed cycles. H
and NaOH of
purity and concentration sufficient for recycling can
be obtained at a plant using sulfuric acid and sodium
hydroxide, with sodium sulfate solutions formed along
with the target product [5, 6].
The possible technologies based on this principle
of processing of spent solutions containing sodium
sulfate were described in . It was suggested to use
for this purpose electrodialysis in a three-chamber
apparatus (electrodialyzer) with two, anion-exchange
and cation-exchange, membranes.
The aim of this study was to determine how the cur-
rent density in the range 2.5310.0 A dm
, initial con-
centration of sodium sulfate (50 and 100 g dm
dialyzate composition affect the current efficiency by
sulfuric acid and sodium hydroxide and the direction
of transfer and amount of water transferred across
the membranes in the course of electrodialysis.
The electrodialyzer is shown schematically in Fig. 1.
It comprises clamping plates 1, 9, anode chamber 2,
anode 3 made of perforated lead sheet, anion-exchange
membrane 4, central chamber 5, cation-exchange
membrane 6, cathode 7 made of perforated nickel
sheet, and cathode chamber 8. The separate elements
are connected via 2-mm-thick rubber sealing gaskets.
The whole set is assembled into a rigid stack by means
of steel coupling bolts. The working size of each
membrane and electrode is 5020 cm.
Fig. 1. Schematic of the electrodialyzer unit. (A) Front view
and (B) side view. (10) Coupling bolts, (11) inlet for water
), (12) inlet for Na
solution, (13) inlet
for water (dilute NaOH), (14) outlet for H
and oxygen, (15) outlet for dialyzate, and (16) outlet for
NaOH solution and hydrogen. The rubber separators are