2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
Fig. 1. Adsorption isotherms of Cu 2+ and Zn 2+ on natural zeolite
Fig. 2. Adsorption isotherms of Pb 2+ and Ni 2+ on natural zeolite
The Langmuir and Freundlich models effectively
described the sorption data with all R 2 values > 0.95.
A d s o r p t i o n o f M e t a l s o n S y n t h e t i c
Z e o l i t e S l o v a k i t e ®
The adsorption of Pb 2+ , ni 2+ , Cu 2+ , and Zn 2+ onto synthetic
zeolite Slovakite ® as a function of their concentrations
was studied in the same conditions as on natural zeolite.
Figs. 3. and 4. illustrate the adsorption isotherms of selected
heavy metals on Slovakite® in single component system.
Comparing the two isotherms on Fig. 3., Cu 2+ adsorption is
usually higher than Zn 2+ . For Zn 2+ , equilibrium adsorption
approaches the value of 42 mg g –1 while for Cu 2+ equilibrium
adsorption still shows higher value than 130 mg g –1 . Fig. 4.
shows a comparison of Pb 2+ and ni 2+ adsorption. For both
metals, equilibrium adsorption still shows an increasing trend
at higher equilibrium concentrations. The cations sorbed from
the solutions followed the same order as on natural zeolite
but the sorption capacity of Slovakite ® was much higher.
The Langmuir and Freundlich models effectively
described the sorption data with all R 2 values > 0.98.
Conclusions
These results show that natural zeolite from nizny Hrabovec
and Slovakite ® can be used effectively for the removal
s504
Fig. 3. Adsorption isotherms of Cu 2+ and Zn 2+ on synthetic
zeolite Slovakite ®
Fig. 4. Adsorption isotherms of Pb 2+ and Ni 2+ on synthetic zeolite
Slovakite ®
of heavy metal cations from solutions. Best sorption capacity
was obtained on synthetic zeolite Slovakite ® , decrease in this
order Pb 2+ > ni 2+ > Cu 2+ > Zn 2+ .The selectivity sequence of
cations is the same on both sorbents, but the sorption capacity
of synthetic zeolite is much higher. The main disadvantage of
synthetic zeolite Slovakite ® its higher cost.
This work has been supported by Scientific Grant Agency
VEGA, project no. 1/4184/07.
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