Интернаука №16 (часть3) 2020 - [38]

Extractability (%)

time(min)

Ga

Zn

4

31.5

72.5

8

76.3

98.2

12

97.9

98.7

16

99.4

98.6

20

98.5

-

47

Журнал «Интернаука»

№ 16 (145), часть 3, 2020 г.

As shown in Table.

Extraction distribution coefficient of Ga (III) and

1, extraction equilibrium times of Ga and Zn were

Zn (II) was calculated by measuring radioactivity of

12.4min and 8min.

samples before and after vibrating. (Table.2)

3.1.2. Determining extraction distribution coeffi-

cient

Table 2.

Extraction distribution coefficient (Kd) of Ga and Zn to TBP extractant polymer resin (static condition)Conc. of HCl

extraction distribution coefficient ( Kd)

(mol·L-1)

Ga

Zn

0.1

0.01

0.08

1.0

1.1

12.3

2.0

27.5

18.8

3.0

104.6

32.8

4.0

816.7

22

6.0

1360

3.8

8.0

1845

1.4

As shown in Table.2, distribution coefficient of Ga

3.2.1. Determining extraction distribution coeffi-

was increased by concentration of HCl. Distribution

cient and column equilibrium constant

coefficient of Ga and Zn were 357.9 and 1317.9 on 6.8

On the column, while 67Ga and 65Zn were extracted

mol·L-1 HCl solution.

on 6 mol·L-1 HCl, maximum eluent volumes ( Vmax) were 3.2. Extractions of Ga and Zn by extractant polymer

416mL and 1.2mL. Base on those, column equilibrium

resin (dynamic condition)

constant and distribution coefficient on the column were

shown in Table. 3.

Table 3.

Equilibrium constant and distribution coefficient of 67Ga and 65Zn on the column

Column equilibrium constant ( D)

Extraction distribution coefficient on the column ( K) 67Ga

331.1

1418.2

65Zn

1.3

5.6

As shown in Table. 3, distribution coefficients un-

3.2.2. Relation between extraction time and ex-

der the kinetic condition were 5% (for Ga) and 9% (for

change ratio ( F) on the column

Zn) higher than ones under the static condition. Equilib-

Variation of exchange ratio of 67Ga (non-radioactive

rium coefficient of Ga was 253.3 times higher than one

Ga concentration; 450μg·mL-1) by time on extractant

of Zn. It showed that extraction rate of Ga was faster resin column was shown as Fig. 1.

than Zn, respectably.

% , 1,2

o

ati

1

reg 0,8

anh 0,6

c

277K

x e 0,4

289K

Ga

308K

0,2

0

0

5

10

15

20

25

extraction time,min

Figure 1. variation of extractability of Ga by time on extractant resin column

As shown in Fig.1, on extractant resin column ex-

67Ga extraction velocity constants and film distribu-

traction equilibrium time of 67Ga was 11min at 308K,

tion coefficient on the column by temperature were

18min at 291K and 24min at 277K.

shown in Table.4.

3.2.3. Kinetics of 67Ga extraction on the column

Table 4.

67Ga extraction rate constants and film distribution coefficient on the column by temperature Temperature (K)

277

289

308

Rate constant ( β)

0.107

0.074

0.218

film distribution coefficient ( Df)

8.0×10-6

5.8×10-5

1.12×10-5

48

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№ 16 (145), часть 3, 2020 г.

By experimental results, it was found that during

and Bt was determined while 67Ga was extracted on early period of column process, film diffusion was rate-extraction chromatograph column. Relation between t determining step and after that, gel diffusion was rate-and Bt at 289K was shown in Fig.2.

determining step. So relation between extraction time

3,5

3

Bt

2,5

2

1,5

1

0,5

0

0

5

10

15

20

t, min

Figure 2. Relation between t and Bt (289K) for Ga extraction on the column

By t-Bt relation at 289K, extraction reaction rate static condition and column equilibrium constant of Ga

constant was 0.23cm-1. So on extractant polymer resin was 254.7times higher than Zn. While 67Ga extracted to

column, extraction process of 67Ga was assumed to be extractant resin was back extracted with 0.05mol·L-1

simultaneous process of film diffusion and gel diffusion.

HCl solution, back-extractability under the static condi-

Activation energy of extraction reaction on the column tion was only 15~20%, but was 94% under the dynamic

determined from relation between lnβ and 1/T was condition and it was found that dynamic condition had E*=14.92kJ·mol-1.

very advantage for back-extraction than static one. From

4. Conclusion

the relation between temperature and extraction equilib-

Extraction characteristics of Ga and Zn on extract-

rium time, it was found that diffusion of Ga ion into ant resin-HCl solution system were found resolved un-surface and interior of resin granule was carried out.

der static and dynamic condition. While concentration

Extraction rate constant was 0.23cm-1 at 289K. On ex-of Ga ion on 6mol·L-1 HCl solution was more than

tractant polymer resin column, extraction process of

300mg·L-1, Ga extraction could be achieved equilibrium

67Ga was assumed to be simultaneous process of film

and Ga saturated extraction capacity of dry extractant diffusion and gel diffusion. Activation energy of extrac-resin was 29.02mg·g-1. Distribution coefficients under

tion reaction on the column was E*=14.92kJ/mol.

the dynamic condition were higher than ones under the

References:

1. Yamamoto, M., Komura, K., Sakanoue, M. A simple sequential separation method of Pu and Am by anion exchange and extraction chromatography. Radiochimica Acta, 29: 205 (1981).