Chemical Industry and Chemical Engineering Quarterly 2012 Volume 18, Issue 4-1, Pages: 563-576
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Equilibrium and kinetic studies of Pb(II), Cd(II) and Zn(II) sorption by Lagenaria vulgaris shell
Mitić-Stojanović Dragana-Linda, Bojić Danijela, Mitrović Jelena, Anđelković Tatjana, Radović Miljana, Bojić Аleksandar Lj.
The sorption of lead, cadmium and zinc ions from aqueous solution by
Lagenaria vulgaris shell biosorbent (LVB) in batch system was investigated.
The effect of relevant parameters such as contact time, biosorbent dosage and
initial metal ions concentration was evaluated. The Pb(II), Cd(II) and Zn(II)
sorption equilibrium (when 98% of initial metal ions were sorbed) was
attained within 15, 20 and 25 min, respectively. The pseudo first,
pseudo-second order, Chrastil’s and intra-particle diffusion models were used
to describe the kinetic data. The experimental data fitted the pseudo-second
order kinetic model and intra-particle diffusion model. Removal efficiency of
lead(II), cadmium(II) and zinc(II) ions rapidly increased with increasing
biosorbent dose from 0.5 to 8.0 g dm-3. Optimal biosorbent dose was set to
4.0 g dm-3. An increase in the initial metal concentration increases the
sorption capacity. The sorption data of investigated metal ions are fitted to
Langmuir, Freundlich and Temkin isotherm models. Langmuir model best fitted
the equilibrium data (r2 > 0.99). Maximal sorption capacities of LVB for
Pb(II), Cd(II) and Zn(II) at 25.0±0.5°C were 0.130, 0.103 and 0.098 mM g-1,
respectively. The desorption experiments showed that the LVB could be reused
for six cycles with a minimum loss of the initial sorption capacity.
Keywords: Sorption, Lagenaria vulgaris, heavy metals, kinetics, isotherms