production of selected secondary metabolites in transformed ...

total flux [mol.m –2 ]
0.7
0.65
0.6
0.55
0.5
0.45
0.4
0 1 2 3 4 5
pH
total flux [mol.m –2 ]
0.4
0 1 2 3 4 5 6
Finally the total diffusion flux showed complex dependency on the ionic strength of
copper(II) solution. For small NaCl additions, the decrease of total flux comes with the
increase of ionic strength, on the contrary substantial increase appeares in higher NaCl
concentration range. Former decrease can be caused by decrease of HA sorption ability,
competitive diffusion of Na + ions or by affecting Cu 2+ solvation. The later increase is not very
clear. It can be supposed that in the solution with high ionic strength bigger Cu 2+ clusters are
solvated and easily took out from the solution.
CONCLUSIONS
This paper deals with the study of copper(II) ions non–stationary diffusion in humic gel.
Main aim was to determinate the influence of individual copper(II) solution properties on the
total diffusion flux across the solution–gel interface.
It was proved that copper(II) ions diffusion across the phase interface is affected mainly by
the initial concentration of copper in the solution and by the time duration of the diffusion.
The influence of other solution properties, such as its pH or ionic strength as well as the type
of copper(II) salt anion is far less important however show interesting dependencies.
Although the applied apparatus was very simple and could be improved for following
experiments (the higher solution volumes should be used) experimental data are fitted well by
the theoretical calculations, so it can be said that this method presented itself suitable for the
wide spectrum of diffusion experiments using humic gel as a very usefull natural–like model.
REFERENCES
[1] Klučáková, M.: Huminový gel jako model pro studium transportu těžkých kovů
v přírodních systémech. CHEMagazín 2004, Vol. 14, No. 3, p. 8–9. ISSN 1210–7409
[2] Klučáková, M., Kaláb, M., Pekař, M., Lapčík, L.: Study of Structure and properties of
Humic and Fulvic Acids. II. Study of Adsorption of Cu + ions to Humic Acids Extracted
from Lignite, J.Polym.Mater 19 (3) 2002
[3] Malenovská, M.: Studium difúzních procesů v huminových gelech. 55 stran. Diplomová
práce na VUT, FCH Brno 2005. Vedoucí diplomové práce Ing. Martina Klučáková
PhD.
[4] Sedláček, P..: Difúze kovových iontů v huminových gelech. 70 stran. Diplomová práce
na VUT, FCH Brno 2006. Vedoucí diplomové práce Doc. Ing. Martina Klučáková PhD.
[5] Klučáková, M., Pekař, M.: Diffusion of Metal Cations in Humic Gels. In Humic
Substances: Nature´s most Versatile Materials (E. Ghabbour, G. Davies Eds.), Francis
& Taylor, New York, 2004, p. 263–74
0.7
0.65
0.6
0.55
0.5
0.45
ionic strength [mol.dm –3 ]
Fig. 8 Total diffusion flux dependency on solution pH (left) and ionic strength (right)
Sborník soutěže Studentské tvůrčí činnosti Student 2006 a doktorské soutěže O cenu děkana 2005 a 2006
Sekce DSP 2006, strana 227