Ind. Eng. Chem. Process Des. Dev. 1986, 25,
537-542
537
Recovery of Sulfuric Acid with Multicompartment Electrodialysis Tlng-Chla Huang' and Ruey-Shin Juang Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan, 70 10 1, The Republic of China
The theoretical expression for the mass transfer of a 1-2 electrolyte in an electrodialysis cell was derived from the Nernst-Planck equation as (Nu ) = 5.547(ReScde/L)1'3, with the assumption that the rate-determining step is the ionic diffusion in the concentration boundary layer. The corresponding empirical correlation for the H,SO,-glucose-xylose system was found as eq 22 with a = 5.26 which was very close to the theoretical one. The effects of the concentration and temperature on the limiting current density were also studied. For the multicompartment electrodialysis, the maximum current efficiency of 51.5% was obtained with a flow rate of 6.95 X lo-' m/s and a H,S04 concentration of 2.64%. The effects of flow rates on the current efficiency were also investigated. It was found that the current efficiencies were greater than 40% with the HISO., concentrations of 1.4%-4.8% and current densities of 49-126 A/m2.
Recently, ion-exchange membrane electrodialysis has become an effective separation process due to the improvements of ion-exchange membrane selectivity, conductivity, and mechanical strength. Electrodialysis has been widely applied in the fields of brine desalination (Sonin and Probstein, 1968; Yamane et al., 1969), acid removal of fruit juice (Farrell and Smith, 1962), concentration of amino acids (Peer, 1958), demineralization of cheese whey (Williams and Kline, 1980),and recovery of metal ions from radioactive and electroplating wastes (Davis et al., 1971; Itoi et al., 1980; Huang, 1981, 1983). Limiting current density is one of the important factors in operating the electrodialytic equipment with ion-exchange membranes. At limiting current density, the socalled concentration polarization will occur and cause the following unfavorable effects: (1) reduction in current efficiency due to the dissociation of water into H+ and OHand (2) reduction in membrane service life due to the precipitation of insoluble salts on the membrane caused directly and indirectly by the pH value changes and H+ and OH- ion migration. In order to prevent the concentration polarization, an accurate prediction of the limiting current density is essential in electrodialysis. (Forgaces et al., 1972; Huang, l974,1977a, 1977b; Sonin and Isaacson, 1974; Mandersloot and Hicks, 1965). At a high concentration of the electrodialytic solution, the ionic transfer due to the Donnan membrane equilibrium effect lowers the current efficiency. At very low concentration, the liquid-phase resistance and the amount of water leakage increase (Chin, 1975). Thus, there exists an optimum concentration range in electrodialysis. Owing to the energy crisis, the utilization of biomass material was very attractive. The H2S0,-glucose-xylose mixture would be present when cellulose material was hydrolyzed by dilute H2S04. In view to industrial application, however, the dilute H2S04should be recovered and reused. In this study, we investigated the mass-transfer rate of the 1-2 electrolyte in electrodialysis by using the sulfuric acid-glucose-xylose system. The results would be used to calculate the limiting current density and then to select an optimum concentration range for a multicompartment electrodialyzer. Theory The ionic mass transfer in dilute electrolyte solutions can be expressed by the Nernst-Planck equation (Newman, 1973) as
* To whom all correspondence should be addressed.
Ni = -2iF~iCiO4- DiOCi + CiP
(1)
The right-hand side of the above equation shows that the electromigration is caused by electrical potential gradients, diffusion by concentration gradients, and convection by the bulk flow, respectively. The equation of continuity is
which describes the concentration distribution of each species in a solution, both charged and uncharged. In this work, it is reasonable to assume that the electrolytes are completely dissociated, C = C+/v+= C-/v-, and the fluid is incompressible, 09= 0. Furthermore, the bulk electrolyte solution is electrically neutral, C+Z+ C- 2- = 0. Hence, at steady state without chemical reaction, the following two equations for the cation and anion are given by substituting eq 1 into eq 2
+
D+V2C + Z+Fu+O(Cb@)= W C D-V2C
+ Z-Fu-O(CO@)= W
C
(3) (4)
Subtracting eq 4 from eq 3 yields
b(COI#J)=
( D - - D+)V2C (Z+u+- Z-u-)F
1
(5)
Substituting both the Nernst-Einstein relation, Di = uiRT, and eq 5 into either eq 3 or eq 4, we obtain
W C = D,V2C
(6)
where D* = (2, - Z-)D+D-/(Z+D+- 2- D-) represents the average diffusivity of the electrolyte. The system considered here is a one-dimensional, steady-state laminar flow. As shown in Figure 1, x denotes the direction of bulk fluid flow and y denotes the direction of current flow. It is reasonable to assume that the mass-transfer rate caused by the bulk fluid flow exceeds that by diffusion in the x direction. Thus, eq 6 can be simplified as (7)
From the momentum balance in two parallel plates, we obtain
v, = %v,[ 2 1-
0196-4305/86/1125-0537$01.50/0@ 1986 American Chemical Society
(;>'I
538
Ind. Eng. Chem. Process Des. Dev., Vol. 25, No. 2, 1986
as t+ = Z+N+/(Z+N+ + Z N - ) and t- = Z-N-/(Z+N++ Z-N-), respectively. From eq 1 and the condition of
feed cutlet
electroneutrality, eq 13 can be expressed as -
_i --
[ (; (&-&) 1
-
k ) W + C + )+
By further assuming complete selectivity of the anionexchange membrane, i.e., t+ = 0, t- = 1, and zero convective velocity a t the membrane surface, the limiting current density can be express as
Figure 1. Ionic transport diagram of ion-exchange membrane electrodialysis.
At infinite dilution, the diffusion coefficients of H+ and Sod2-at 25 "C are 9.312 X and 1.065 X m2/s, respectively. In this case, the concentration polarization occurs first in the proximity of the anion-exchange membrane since DH+Ois larger than Ds02-O. Therefore, a preferable attention would be paid to the anion-exchange membrane. Because of the large Schmidt number (above 250) selected in our experiment, it is assumed that the thickness of the velocity boundary layer is far larger than that of the concentration boundary layer (Newman, 1973). Hence, the boundary condition and eq 8 can be simplified by setting C = Co at y = m and by using the Taylor series expansion at y = -B, respectively. Therefore eq 8 becomes
v,
= 3(V)[ 1 +
(g)]
C=O
(1la)
y=m
c=co c=co
(1lb) (1lc)
Solving eq 10 by using the method of combination of variables and introducing two dimensionless groups Re (=de( V)/v)and Sc (=v/D,), we obtain (12) where I? is the Gamma function and 5 = [l + (y/B)](ReScBl12x)'13. The current in an electrodialysis can be expressed by the movement of ions in an electrolyte solution, and the current density 1 a t any point in the solution is given by the summation of the fluxes of the various ion species times their charges, i.e.,
+ ,EN-)
(16)
In the present system, the Nusselt number is defined as
( N u )=
(&,)de - -N-l,=-de -2- D- FCo D-Co
(17)
Therefore,
(
3
( N u ) = 1.849 1 - - (ReS~de/L)'1~ (18)
(19)
Equation 19 is the theoretical equation for relating the mass-transfer rate to the dimensionless groups at limiting current density.
y=-B
i=l
- 1)2(ReS~$)''~
( N u ) = 5.547(ReScde/L)'13
with boundary conditions
= F g Z i N i = F(Z+N+
1.849Z-D-F(
For the 1-2 electrolyte, 2, = 1 and 2- = -2; thus,
Substituting eq 9 into eq 7 , we obtain
x = o
The average limiting current density ( ili,) is
(13)
The transfer number of the cation and anion are defined
Experimental Section Reagent and Material. All the reagents used in this experiment are analytical grade and without any further purification. Glucose and sulfuric acid are offered from Merck Chemical Co. Xylose and glycerin are purchased from Sigma Chemical Co. and Wako Pure Chemical Industry Ltd., respectively. Ion-ExchangeMembranes. Ion-exchange membranes, Selemion CMV and Selemion AMV, used in this study are manufactured by Asahi Glass Co. of Japan. They are homogeneous membranes, and their properties are listed in Table I. Apparatus. The apparatus used in the present work for measuring the limiting current density is shown in Figure 2. It is a parallel planar electrodialysis cell. The Selemion CMV and AMV were fixed on two separate PMMA plates, and a rubber gasket was placed in the middle. The center of the cell has an opening 4 x 5 cm, which represents the effective area of electrodialysis. The temperature of the electrodialyte solution was kept constant by circulating constant-temperature water in the stainless steel jacket. The electrodialyte solution was circulated by a pump to avoid drastic concentration changes in electrodialysis. The multicompartment electrodialyzer, Selemion Electrodialyzer Laboratory Model Du-Ob, used in this study
lnd. Eng. Chem. Process Des. Dev., Vol. 25, No. 2, 1986 539
Table 11. Specifications: Electrodialysis Stacks Type DU-Ob DU-Ob 16 X 24 membrane size, cm 209 effective area, cm2/membrane 2 membrane separation, mm 11 std no. of pairs of membranes 11 cation membrane 11 anion membrane carbon anode stainless steel SUS-27 cathode chloroprene gaskets polypropylene distributors PVC or polypropylene separators hrad PVC electrode frame bakelite press frames sus-27 press bolts
Table I. Specifications: Selemion CMV and Selemion AMVa Selemion Selemion CMV AMV and remarks high acidic high basic ion-exchange ion-exchange membrane membrane Tevilon cloth Tevilon cloth base material (PVC) (PVC) 0.11-0.14 0.12-0.15 thickness, mm 3.0-4.5 2.5-3.5 effective electrical 0.5 N NaCl resistance, R/cm2 a t 25 "C 190-230 280-320 specific electrical 0.5 N NaCl resistance, (Q/cm) a t 25 "C 0.94-0.96 transport no. 0.91-0.93 4-7 bursting strength, 6-8 Mullen test kg/cm2 Note: (1) Thickness by Micrometer in wet state. (2) Effective and specific resistance measured by ac 1000 C / s current in 0.5 N NaCl solution a t 25 "C. (3) Transport number obtained for membrane potential resulting from membrane separation of 0.5 N NaCl and 1.0 N NaCl solutions at 25 OC.
-
__
.c._
,.-----1.
A
I
onim - exchange membrane
The effective voltage (AE) applied to the diluting compartment can be expressed (Kitamoto and Takashima, 1970) as
AE= AEapplied - 2RT '
". - (ra + r c ) I - m e l e c t r o d e overpotential ad
(20)
K : cation-exchange membroce
effective :ks-:A I -+I---
or-
f
circufont out
stoinless
-
steel f r m feed k l e t
1
Figure 2. Front and side view of two-dimensional flow channel.
was produced by Asahi Glass Co. of Japan. Its specifications are listed in Table 11. Experiment. In general, limiting current density could be determined from the following three different combinations of the experimental data: (1) current and pH value, (2) resistance and reciprocal of current density, and (3) current and voltage (Cowan and Brown, 1959; Rosenberg and Tirrell, 1957). The last type of measurement was employed in this work. The applied voltage was successively increased by an equal amount, and then the current density was measured. As usual, the limiting current density is determined from the corresponding value where the inflection point exists in the current density-voltage plot. However, this method had some disadvantages, such as the uncertainty for indicating the inflection point. Thus, we took the first-order difference of current densities for a certain voltage change, and the limiting current density was obtained by taking the average of the two current densities at which their first-order difference was minimum.
where m a p p l i e d is the applied voltage measured in the diluting compartment, a, and ad are the activities of the diluting and concentrated solutions, respectively, and rc and ra are the electric resistances of the cation- and anion-exchange membranes, respectively. Since the concentration of the diluting and concentrated solution was nearly kept equal, the second term in eq 20 was cancelled. The values of ra and r, listed in Tabel I are only 3 and 4 Q/cm2,respectively. Compared with the liquid-phase resistance, they can be neglected. In order to minimize the measurement error in the applied voltage due to electrode overpotential, as shown in Figure 2, two pieces of platinum wires were used to measure the potential drop between the membranes. Thus, the measured voltage is considered as the effective voltage, aE. In order to compare the experimental results with eq 19, we intended to find the values of a, b, c, and d in the following empirical equation, = aRebScc(de/L)d. Two of the dimensionless groups (Re, Sc, and de/L) were fixed in sequence and the effects of the remaining one on the limiting current density was then studied. Besides that, we also investigated the effects of temperature and concentration on limiting current densities. The solutions used were 6 w t % xylose 1.8 wt % glucose and various concentrations of sulfuric acid. In the experiment of multicompartment electrodialysis, the current efficiency (17) was measured by changing the concentrations of sulfuric acid under several sets of fixed current, and 17 was calculated according to
+
1
-At
ZiF
where v d is the total volume of the diluting solution, Ac is the concentration difference of H2S04in time interval At, and I is the current. Results and Discussion Because organic substances such as glucose and xylose can hardly cross the ion-exchangemembrane, we consider only the transfer of sulfuric acid (Anderson and Wylam, 1956; Jarvis and Tye, 1960; Keristsis, 1981) in this work. Effects of H2S04Concentrations on Limiting Current Densities. The limiting current densities were
540
Ind. Eng. Chem. Process Des. Dev., Vol. 25,
No. 2, 1986
15’
-
10
3
IO
L
50 100 200 400
IO
E
10’
Re
2
Figure 5. Relation diagram of and Re at varying Sc. For (A) s c = 346/s = 0.024, r = 0.980, (0)sc = 466/s = 0.017, r = 0.989, (A)Sc = 630/s = 0.011, r = 0.993, and ( 0 )Sc = 745/s = 0.021, r = 0.983.
51
i
01
02
03
04
05
% HzSO, + 6 % Xylose + I 8 %Glucose
Figure 3. Linear dependence of limiting current on the concentration of sulfuric acid at varying Re. For (A) Re = 50/s = 0.04 mA, r = 0.987, (0) Re = 1OO/s = 0.06 mA, r = 0.981, (A)Re = 200/s = 0.04 mA, r = 0.992, and ( 0 ) Re = 400/s = 0.05 mA, r = 0.994. 1
fO1
024%H z s 0 4 + 6 % %y1ose +l8%Glucose Re = 400
I30
Sc = 59-256
1
f/
/
1
~ 0 2 4 % u Z S 0 .+ 6 % X y l o s e + 18%Glucorei
100
I
2 100/
-i r=2 5 ~ de/L = 0 65
I
i
10000
1000
sc Figure 6. Relation diagram of NU),,,^^ and Sc at varying Re. In this series of experiments, Sc was adjusted by adding glycerin into the electrodialytic solution in which the glycerin concentration ranged from 0 to about 20 vol 70. For (A) Re = 50/s = 0.023, r = 0.962, (A)Re = 1Oo/s = 0.028, r = 0.957, (0) Re = 2OO/s = 0.017, r = 0.971, and ( 0 )Re = 400/s = 0.019, r = 0.968.
b in eq 21 to be 0.322 by the method of least squares. Effect of Schmidt Number on ( N u )exptl. From the experimental data, the relationship between S c and (Nu)exptl is shown in Figure 6 for four different Reynolds 1 I 10 20 30 40 50 60 numbers, 50,100,200, and 400. In this work, the solution Temp I “CJ viscosity was adjusted by adding glycerin into the electrodialytic solution; its concentration ranged from 0 to Figure 4. Dependence of limiting current on temperature. s = 0.11 mA, r = 0.973. about 20 vol 5% , in which case the solution viscosity was in the range of 1.094-1.902 cP. measured with various HzS04concentrations at different From the result of Figure 6, the value of c is found to Reynolds number while keeping the temperature (25 “C), be 0.355. It is also indicated that the greater the Sc, the de/L(0.65), and Schmidt number (256) constant. These greater the (Nu)expt, when Re and delL are constant. results are shown in Figure 3. It was found that a linear Basically the increase of Sc corresponds to the increase of relationship existed between the limiting current density solution viscosity, which results in increasing the boundary and the H2S04concentrations. As indicated in eq 17, the layer thickness and reducing the mass-transfer rate. In limiting current density is proportional to the solution fact, ( N u ) is proportional to the one-third order of visconcentration at constant ( N u ) . cosity from the relationships of eq 19 and Dip/ T constant Effect of Temperature on Limiting Current Den(Newman, 1973),whereas ( iti,) is inversely proportional sities. The limiting current densities were measured with to the two-third order of viscosity from eq 17. Therefore, various temperatures for Sc ranging from 59 to 256 at the from eq 13, we obtain the result that the mass-transfer rate HzS04concentration of 0.24%, de/L = 0.65, and Re = 400. decreases and ( N u ) increases with the increase of the S c These results are shown in Figure 4. A linear relationship number. was also found to exist between limiting current densities Effect of de/L on ( N u)exptl. At various values of de/L and temperatures. As also obtained by Miyoshi et al. (0.65, 0.46, and 0.32) and Re (50, 100, 200, and 400), the (1976),they explained this result in terms of the diffusivity relationships between de/L and at 25 “C are effect. However, in the present work, eq 19 could be reshown in Figure 7 for the H$04 concentration of 0.24% arranged as (ih) = 5.5471Z-IFCo[( V)/(deL)1’’3(D_3/ol)’/3. and Sc = 256. It is found that the value of d is 0.318, and It was evident that the temperature effect was resulted the greater the (de/L), the greater the (Nu)exptl. from the diffusivity change. Effect of the (ReScde/L) Group on NU),,^^^. Effect of Reynolds Number on (Nu)exptl. The Summarizing the above results, we can write could be calculated from eq 17, because the concentration polarization occurred first near the anion(Nu)exptl = uRe0~322Sc0~355(de/L)o~318 (22) exchange membrane. The relationships between Re and Now, substituting the experimental data into eq 22 and (Nu)exptlwere measured at 25 “C by varying Sc a t the H,S04 concentration of 0.24% and de/L = 0.65. These vs. Re0.322S~0.355(de/L)o,318 as shown in plotting (Nu)exptl results are shown in Figure 5. We obtained the value of Figure 8, we found from the slope the value of u to be 5.26.
Ind. Eng. Chem. Process Des. Dev., Vol. 25, No. 2, 1986
1
1
Now rate -16 6 7 m l h e c
T =25T Sc = 256 1024%H2S0.
+ 6 %Xylose +
10
01
0"
10
10
IO-
(de/L)
A
Figure 7. Relation diagram of (Nu)expt, and de/L a t varying Re. For (A)Re = 50/s = 0.022, r = 0.961, (A)Re = l O O / s = 0.031, r = 0.948, (0) Re = 200/s = 0.018, r = 0.973, and (0)Re = 400/s = 0.015, r = 0.981. I
300
p 200
-2 -?
i
"
"
n I
'
I
fool 0 0
10
20
30
~ ~ 0 3 2 1 scou47 6
a 046%.
40
50
60
(de/~)03'e4
Figure 8. Relationship of (Nu)expt, and Re0~322S~o~366(de/L)o~318 at T = 25 "C. s = 4.746, r = 0.985.
This is slightly different from the theoretical values in eq 19. This may be due to the measurement error on membrane separation resulting from nonuniform flow pressures in the diluting compartment. Multicompartment Electrodialysis. All the experiments were carried out for 1h at 23.4 "C with various fixed currents (0.5-2.7 A) and H z S 0 4 concentrations (0.46%-5.49%). The flow velocity was chosen as about 6.95 X lo-, m/s. In this case, the flow pressure of the diluting compartment is greater than that of concentrating compartment by 0-20 mmHg. According to the operating conditions and the specifications of the electrodialyzer listed in Table 11, the minimum limiting current calculated from eq 17 and eq 22 is 2.94 A, which is greater than the upper value of 2.70 A in our study. Furthermore, the limiting current density in the multicompartment electrodialyzer with spacers is greater than that predicted at the same operating conditions in a simple unicompartment electrodialysis cell (Miyoshi et al., 1982). Thus, all the operation conditions were adequate. The plots of current efficiency vs. current for various H2S04concentration are shown in Figure 9. At a constant current density, the current efficiency is low when the HzS04concentration is also low, because of a larger amount of water leakage. But at higher HzS04concentrations, the current efficiencies remain low because of the ionic permeance created by the Donnan membrane equilibrium effect. As indicated by Chin (1975) in studying the electrodialysis for NaC1, MgC12, and CaC1, solutions, water leakage decreased with increasing concentration of the feed solution and with an increase in the current density, since the concentration had more effect on the amount of solvent
0.
386%.
0081%. 4944
o 177%,
550%.
v264%,
541
542
Ind. Eng. Chem. Process Des. Dev., Vol. 25, No. 2, 1986
r--
'
3
t,
-1
(264%H2S04+18%Glucose+
I = I76
e, 251-
6%Xylosei
Arrp
~-.1
10
!
i
20
15
Flow rate
I
imi/sec)
Figure 10. Relation diagram of current efficiency a n d flow rate of diluting solution.
C = electrolyte concentration at any time, mol/m3
D i= diffusion coefficient of component i, mz/s D, = average diffusion coefficient of electrolyte, m2/s de = equivalent diameter ( = 4 B ) ,m F = Faraday's constant (=96487), CJequiv i = current density, A/m2 4 = effective length in electrodialysis, m Ni = molar flux of component i , mol/(s.m2) Ri = number of mole change of component i caused by chemical reaction per unit time per unit volume, mol/(m3.s) r = correlation coefficient for checking the applicability of linear regression s = standard deviation ti = transference number of component i 4 = mobility of component i, m2.mol/(J.s) V = bulk fluid velocity, m/s ( V ) = average velocity, m/s Zi= valence of component i Greek Letters
tration difference (qH2p), membrane fouling ( q m ) ,current leakage (qi), electrolysis (qe)and flow rate (73 (Matsuzaki et al., 1981). The current efficiency ( q ) can be expressed as 7) = qqqH20qmqiqeqP Therefore, the influence of the flow rate is limited to a certain degree. Some factors such as electric permeance, electrolysis, and water leakage are difficult to control, because the Selemion CMV and AMV possess microscopic passageways. Furthermore, the anode is made of carbon which may react with sulfuric acid. Actually, for desalination from seawater, Matsuzaki et al. (1981) had found that qq was theoretically expressed as functions of the ratio of the flow rate of leakage to raw water and the ratio of desalinated salt weight of leakage to raw water; qH?o was expressed as only a function of the current density in the temperature range of 15-45 OC and had a constant value (about 0.88), in the case of the current, the density was greater than 200 A/m2, and vm in the case of nonmembrane fouling is 0.96 in view of the membrane transport number. However, other factors were not investigated experimentally or theoretically. It was found that the current efficiencies were greater than 40% for H2S04concentrations of 1.4%-4.8% and current densities of 49-126 A/m2. However, for demineralization of sugar solutions, Anderson and Wylam (1956) had pointed out that ion-exchange membrane electrodialysis was more suitable than the ion-exchange resin method, since there was no danger of hydrolysis or degradation of sugar. In the present work, the amount of hydrolysis or degradation of glucose and xylose was expected to be few because of the low H2S04concentration and low temperature. If the possibility of sugar degradation is taken into consideration, electrodialysis can be applied while operating in the range which current efficiencies are greater than 40% (McRae and Leitz, 1972; Chin, 1975). Acknowledgment This work was supported by a grant from the National Science Council of The Republic of China, to which we express our thanks. Nomenclature 2B = the width of the membrane cell, m C, = molarity of component i, mol/m3 Co = initial concentration of electrolyte, mol/m3
9 = p
current efficiency
= viscosity of fluid, CP
v = kinematic viscosity, mz/s u+, v- = number of cation and anion in one electrolyte molecule 6 = electrical potential, V
Subscripts +, - = cation and anion
( ) = average character lim = limiting character
Superscripts - = vector character = infinite dilution character Registry No. H2S0,, 7664-93-9; glucose, 50-99-7; xylose, 5886-6.
Literature Cited Anderson, A. M.; Wylam, C. B. Chem. Ind. 1956,March, 191 Chin, T. R. Int. Chem. Eng. 1975, 75(2), 280. Cowan, D. A.; Brown, J. H. Ind. Eng. Chem. 1959,57, 1445. Davis, T. A.; Wu, J. S.; Baker, B. L. AIChE J . 1971, 7 7 , 1006. Farreil, J. B.; Smith, R. N. Ind. Eng. Chem. 1962, 5 4 , 29. Forgaces, C.; Ishibashi, N.; Leibovitz. J.; Spiegler, K. S.Desalination 1972, 1 0 , 181. Huang, T. C.; Chou, J. Y. K ' o Hsueh Fa Chan Yueh K'an 1981, 9 , 1069. Huang, T. C. J . Chem. Eng. Data 1977a92 2 , 422. Huang, T. C.; Yu, I. Y.; Lin, S. B. Chem. Eng. Sci. 1983,38, 1871. Huang, T. C.; Wang, T. T. Desalination 1977b,2 7 , 327. Huang, T. C.; Yu, I.Y. J . Chin. Inst. Chem. Eng. 1974,5 , 39. Itoi, S.;Nakamura, I.;Kawahara, T. Desalination 1980,32. 383. Jarvis. J. W.; Tye, F. L. Chem. Eng. J . 1960,620. Keristsls, G. D. US Patent 4 302 308, 1981. Kitamoto, A.; Takashima, Y. J . Chem. Eng. Jpn. 1970,3 , 182. Mandersloot, W. G. B.; Hicks, R. E. Ind. Eng. Chem. Process Des. Dev. 1965,4 , 304. Matsuzaki, H.; Kuroda, 0.: Takahashl, S.; Sawa, T. Nimon Kaisui Gakkaishi .. 1981,35 (3), 149. McRae, W. A.; L e k , F. 8 . "Recent Developments in Separation Science"; Li. N. N., Ed.; Chemical Rubber Co.: Cleveland, 1972; Vol 11, p 157. Miyoshi. H.; Fukumoto, T.; Kataoka, T. Nippon Kaisui Gakkaishi 1976,30 (3), 154. Miyoshi. H.; Fukumoto, T.; Kataoka, T. Nippn Kaisui Gakkaishi 1982,36 (1). 38. Newman, J. S. "Electrochemical Systems"; Prentice-Hall: Englewood Cliffs, NJ, 1973. Peer, A. M. J . Appl. Chem. 1958,Jan, 8 . Rosenberg, N. W.; Tirrell, C. E. Ind. Eng. Chem. 1957,4 9 , 780. Sonin, A. A.; Isaacson, M. S. Ind. Eng. Chem. Process Des. Dev. 1974, 73, 241. Sonin, A. A.; Probstein, R. F. Desalination 1968,5 , 293. Williams, A. W.; Kline, H. A. US Patent 4227 981, 1980. Yamane, R.; Ichikawa, M.; Mizutani. Y. Ind. Eng. Chem. Process Des. Dev. 1969,6 (2), 159.
Received f o r review October 31, 1984 Revised manuscript received September 17, 1985 Accepted October 8, 1985
