3. Results and discussion
3.1. Dithizone adsorption onto silica surface
The adsorption of H2Dz onto SG and SP
from chloroform, toluene, hexane and their mixtures
was studied. The best reagent adsorption
was observed in the case of hexane. The kinetics
experiments have shown that the equilibrium of
H2Dz adsorption onto SG and SP (0.02 g) surface
from hexane solution (10 ml) was reached
in 15 and 30 min, respectively. The isotherms
are represented in Fig. 1. The values of H2Dz
maximum adsorption onto SP and SG were 46
and 40 mmol g−1
, respectively. In the present
work H2Dz-SG and H2Dz-SP with this reagent
content on the surface were used.
3.2. Zn(HDz)2 adsorption onto SP surface
The adsorption of Zn(HDz)2 onto SP surface
from chloroform and its mixtures with hexane
was studied. The best complex adsorption was
observed in the case of mixture with the ratio
chloroform:hexane=1:9. The kinetics experiments
have shown that the equilibrium of
Zn(HDz)2 adsorption onto SP (0.01 g) surface
from this mixture (5 ml) was reached in 5 min.
The shape of isotherm of zinc dithizonate adsorption
(Fig. 1(b)) testifies the stronger complex
binding with the SG surface, in contrast to
H2Dz. It is caused probably by its plane fixation
[11]. In the present work SP containing 8 mmol
g−1 Zn(HDz)2 was used.