IAEA1229 ISOTHERM.

1. NAME OR DESIGNATION OF PROGRAM:  ISOTHERM.

3. DESCRIPTION OF PROGRAM OR FUNCTION

The Ion Exchange program ISOTHERM can be used to create Ac against As, and ln(Kc) against Ac  plots and to calculate the thermodynamical equilibrium constant Ka,  Gibbs free energy, and the values of exchanger phase activity coefficients fA and fB, by a numerical integration of the polynomial equations of ln(Kc against the Ac plot.

4. METHOD OF SOLUTION

The program is used to input a set of isotherm  data points at a given total solution normality. The program "best fits" a series of polynomial equations (depending on the number of input points) using Gauss elimination and numerical integration.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

In cases where partial exchange occurs, normalization of the isotherm can lead to problems, as the normalization can lead to an exaggeration of experimental errors at the isotherm, resulting in plots of ln(Kc) against Ac(N) for different solution phase conditions which do not closely coincide at Ac(N)--0 and especially at Ac(N)--1. It appears  that normalization is best avoided. This was done on the basis of new factors: (i) Ac(maximum) should be equal to or less than one. (ii) If the ratio of Ac(highest)/Ac(max.cal) is greater than one, Ac(maximum) was chosen as Ac(highest) instead of Ac(max.cal) which was calculated from the best fitting polynomial.

6. TYPICAL RUNNING TIME:

7. UNUSUAL FEATURES OF THE PROGRAM

Two new subroutines were included  to save new data in files and read them out again.

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- R.P. Townsend and F. Fletcher:
  "Proceedings of the Fifth International Conference on Zeolite"
  L.V. Rees, Editor (1980)
- P.W. Atkins:
  "Physical Chemistry", 4th Edition
  Oxford University Press (1990)
- E. Glueckauf:
  Nature, 163-414 (1949)
- G.L. Gaines and A.J. Walker:
  J.Chem.Phys. 21, 714 (1953)
- R.M. Barrer and A.J. Walker
  Trans.Faraday Soc., 60, 1-1 (1964)
- R.M. Barrer and J. Klinowski
  J.C.S.Faraday 1, 70, 2080 (1974)

- J.Kh.Abou-Jamous, B. Adbul Ghani, M. Haswani:
  Modified Computer Program for Plotting and Interpretation of Ion
  Exchange Isotherm
  Damascus - Syrian Atomic Energy Commission

11. MACHINE REQUIREMENTS:  IBM PC AT-compatible.

The program was installed at the NEA Data Bank both on  a PC/Pentium75 (75 MHz) with 16 MB of RAM; and on a DEC VAX 6000-510 computer.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  MS-DOS Vers.3.2 or later. Compiler MS-FORTRAN Vers.2.2

The installation of the program at the NEA Data Bank was done on the PC under MS-DOS 6.2 and using the Lahey Fortran compiler Version 5.20; and on the VAX under VMS Version 6.1 and using the VAX Fortran compiler Version 6.2.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHORS

J.Kh.Abou Jamous, Bashar Adbul Ghani, Michel Haswani
Syrian Atomic Energy Commission
P.O. BOX 6091
DAMASCUS, Syria

File name	File description	Records
IAEA1229_01.001	Information file	77
IAEA1229_01.002	Fortran source code	511
IAEA1229_01.003	Executable for PC	0
IAEA1229_01.004	Error messages for Lahey compiler	0
IAEA1229_01.005	Sample input file	11
IAEA1229_01.006	Sample output file with Lahey compiler	272
IAEA1229_01.007	Sample output file with VAX	272
IAEA1229_01.008	DOS file-names	7