samples) were added prior to the column separations (see Experimental, procedure C). From the results shown in Table IS’ it is seen that in all cases quantitative recovery of gallium and indium was achieved. The values given in Table IV of the gallium yields have been corrected by subtracting the gallium originally present in the samples from the gallium added. Iron(II1) ions present in the sorption solution shorn a behavior very similar to that of gallium, so that a separation of the two elements under these experimental conditions is inipossible. Precision. T h e following values for precision were obtained: standard
deviations in the 2-methoxyethanol-lhydrochloric acid system; + 1.64 (al), 1 1 . 7 2 (Ga), and 3~1.68(In): standard deviations in the acetone-hydrochloric acid system; 1 1 . 7 5 (Ga), +l.r32 (In), and 3~1.55(*\l). The 5-nig. quantities of gallium and indium and the 100-mg. amounts of aluminum added and subsequently found (Tables 11, 111, and IV) were taken as the basis for the calculation of the standard deviations. LITERATURE CITED
( 1 ) Denisova, S . E., Tsvetkova, E. V., Zavod. Lab. 27, 656 (1961). ( 2 ) Gregory, G. R. E. C., Jeffery, P. G., Talanta 9 , 800 (1962).
( 3 ) Kiesl, W., Bildstein, H., Sorantin, H., Mikrochim. Acta 1963, p. 151. ( 4 ) Korkisch, J., Arrhenius, G., AIVAL. CHEM.36, 850 (1964). ( 5 ) Korkisch, J., Feik, F., Anal. Chim. Acta. in Dress. ( 6 ) Kraus,’K. A., Selson, F., Smith, G. W., J . Phys. Chem. 58, 11 (1954). ( 7 ) Laskorin, B. S . , Ulvanov, V. S., Gviridova, 1%..4.,Arzhatkin, A. AI., Yuzhin, .4. I., At. Ener. ( U S S R ) 7, 110 (1959). (8) Xadezhina, L. S., Zh. Anal. Khim. 17, 383 (1962).
RECEIVEDfor review June 4, 1964. Accepted July 30, 1964. Work supported by The Petroleum Research Fund ( P R F grant S o . 1587-A3) administered by the Smerican Chemical Society.
Anion Exchange Behavior of Alkali and Alkaline Earth Elements in Dioxane-Mineral Acid Media R. R. RUCH, F. TERA,, and G. H. MORRISON Department o f Chemistry, Cornell University, Ithaca,
b A distribution siudy was made of the behavior of Group I and II elements between the solution phases dioxane-HCI-HsO and dioxaneHN03-HZ0 and Dowex 1-X8 resin, and the most favorable separation conditions were ascertained. Group II elements (Mg, Ca, Sr, and Ea) were separated from each other b y a dioxane-HNO3-HzC) eluent using a gradient elution technique. Only a partial separation of Group I elements was effected by the same technique. A sepa,ration of Group I from Group II eniploying dioxaneHCI-HzO as eluent was demonstrated. The effect of dioxane content, acid concentration, loading, and analytical advantages are discussed.
I
EXCHAKGF. coupled with mixed solvent elution techniques has proved to be successful as a general separation method. Both anion and cation exchange resins combined with various alcohol or a,cetone solutions of mineral acids as sidvents have been employed for the separation of transition elements (1, 6 , 20), U and T h (11-I3), the rare earths (3,4,1 6 ) , and Group I and I1 elements ( 5 , 7 , 8, 19). Dioxane offers considerable promise in mixed solvent ion exchange systems because of its extremely !ow dielectric constant [2.2], high miscibility .ivith aqueous acid media, and fair solubility for some inorganit. salts in mixed aqueous solutions. The HxO3 and HC1 components of the eluent solution lend theniselves to simplicity of removal ON
N. Y .
after separation, whereas many good selective ion exchange systems for Groups I and I1 in aqueous media containing complexing agents (15, 17, I S ) may require destruction for removal. I t might also be noted that dilute HCl or “ 0 3 alone will not cause Groups I or I1 to be absorbed on an anion exchange, column (8, 1 4 ) ; it is mandatory that an organic solvent be present in order to enhance complex formation or ion association, thus causing the species to have a tendency to exist in the resin phase (11). Although studies involving lithium in mixed solvents have been reported (9, I O ) , no systematic fundamental study with a low dielectric, mixed solvent anion exchange system has been applied to Group I. Further, it was anticipated that a low dielectric system might enable one to perform Group I1 separations a t lower over-all percentages of organic solvent than those reported with alcohol-HS03-H20 systems ( 7 , 8). Thus both the dioxane”03-Hz0 and dioxane-HC1-HnO systems were examined with a strongly basic anion exchange resin for most elements in Groups I and I1 over a series of different dioxane and acid concentrations. Batch experiments were first employed to survey the whole realin of concentrations involved and then column techniques were used to evaluate the more favorable a n a l y t d possibilities. EXPERIMENTAL
Reagents and Solutions. Hydrochloric acid, nitric acid, and salts of Group I and I1 elements were of
reagent grade and used directly with no further purification. The 1,4dioxane used specifically was Fisher “Certified” reagent grade. For most experiments Dowex 1-X8, 100 to 200 mesh (J. T. Baker Co.) was used. The resin was purified in the chloride form by passing, in a column operation, a large excess of 6-11 HCl, washing throughly with excess distilled, deionized water until a negative acid test, passing absolute ethyl alcohol. air drying for a day, heating a t 70” C. for 2 hours, and then storing in a desiccator dried by CaClz until used. The nitrate form of the resin was prepared exactly as the chloride using 5 X H Y 0 3 . Stock solutions of alkali and alkaline earth chlorides and nitrates were prepared by dissolving the respective salts in either O.lZ1 HCl or 0.1.11 HNOa as desired. Radioactive tracers S a z z , K42, RbS6,Ba133,and SrS5were added to their respective solutions. These tracers were obtained from Oak Ridge h’ational Laboratory and IsoServe Inc. Sample solutions of about 51 m!. were pre1)ared by mixing 1.0 ml. of stock metal solution to a solution of known volumes of acid solution and dioxane. Calculations involving concentrations were made neglecting the small (-1%) volume changes of the equilibrated systems. For all sample solutions used the concentration of metal used, unless otherwise stated, was 1.4 i 0.1 x 10-35. Thus a 0.98M H S O , solution, 1.4 X 10-3S in Ea, was prepared by adding 1.0 ml. of 0.0735 Ba(?;O& (0.1JI in HSO3) with 10 ml. of 5 . 0 X HN03 and 40 ml. of dioxane. Batch
Experimental
Procedure.
I n all cases a nitrate solution was used with a nitrate form resin, a chloride solution with a chloride form resin. To a n exactly known weight (approxiVOL. 36, NO. 12, NOVEMBER 1964
231 1
Table 1.
K D Values for the System Dioxane-HCI-H20
Over-all concentration of mixed solvent svstema -___.Dioxane, HC1,
.Lw
CI /C
Li
Na
K
Rb
88 88 78 78 78 59 59 59 39 a
0 10 14 13 13 16 0 002 24 27 27 30 0 49 2 4 2 1 2 8 2 8 0.10 2.0 2.6 3.6 2.8 0,002 0.6 1.7 3.9 3.2 2.9 50.3 1.0 0.8 50.1 0.49 0.6 0.5 1.0 0.6 0,002 0.3 0.5 0.8 0.3 2.9 0.7 0.3 shown in Figure 7 , using 7870 dioxane-0.49.U HC1 as an eluent demonstrates the feasibility of separa-
X
tion of Group I from Group II. These two elements represent the least favorable separation factor between the two groups. Batch experimental data (Table I) show R b typical of Group I whereas M g has the lowest KO for Group 11 elements. The group separation was further confirmed by a similar separation of R b from I3a. The approach to separations involving dioxane-acid coupled with gradient elution has offered several analytical advantages. Group II elements can be separated in a time comparable to most ion exchange methods used presently and more important the volumes involved are very small eliminating any additional concentration. Further, the gradient elution technique is capable of automatic treatment. .Us0 the fact that the eluate is merely a simple aqueous HC1 or HxO3 solution containing a volatile organic substance might be an advantage in those cases where additional cheinical steps are involved. The separation of Group I from Groul) I1 can now be accomplished by an anion exchange approach. This
(4) Frjtz, J. 8.) Greene, R. G., Ibid., 36, 1090 (1964). (5) Fritz, J. S.,Pietrzyk, D. J., Tulanta 8, 143 (1961). ( 6 ) Fritz. J. S.. Itettie. T. A , . ASAL. CHEM.34. 1362 (1962): ( 7 ) Fritz, J: S., \?ski, H., Ibzd., 35, 1079 f 196.3) \ - - - - ,
(8) Fritz, J. S., Waki, H., Garralda, B. B., I b d , 36,900 (1964). ( 9 ) Katzin. L. I., Gebert. E.. J . 9 m . Chem. SOC.7 5 , 801 (1953).
(10) Kennedy, J., Davies, R . V., J . Inorg .Vucl. Chem. 1 2 , 193 (1959). (11) Korkisch, J., Janauer, G. E., Talanta
9,9.57 (1962). (12) Iiorkisch, J., Tera, F , A s . 4 ~ Cm&i. .
33. 1264 i1961). (13) 'Korkisch, J., Urubay, S.,Talanta 11, i 2 1 (1964). (14) Kraus, K. A., Selson, F., Proc Intern. Conf. Peaecjul Cses i l t . Energy 7 , 113 i1955j. (15) Lerner. 11..Rieman. E., 111. ANAL. CHEM.261 61O'( 1954). (16) Narple, L. W., J . Inorg. .Yucl. Chem. 26,859 (1964). (17) Nelson, F., J . Am. Chem. SOC.7 7 , 8 1 3 (1955j. (18) Nelson, F., Kraus, K. A , , Ibid., 77, 801 (19SS). (19) Nevoral, V., Z. Anal. Chem. 195,332 (1963). ( 2 0 ) Van Erkelens, P. C., Anal. Chim. S c t a 25, 42 (1961). I
,
,
RECEIVEDfor review July 27, 1964. Accepted September 8, 1964. This research was supported by the Advanced Research Projects Agency.
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