Adsorption and desorption of uranium(VI)
from dilute aqueous solutions by
Eucalyptus citriodora
distillation sludge was studied in a batch mode. The
potential of
Eucalyptus citriodora distillation sludge to
remove uranium(VI) from aqueous solutions has been
investigated at different conditions of solution pH, metal
ion concentrations, biosorbent dosage, biosorbent particle
size, contact time and temperature. The results indicated
that biosorption capacity of
Eucalyptus citriodora distillation
sludge was strongly affected by the medium pH, the
biosorbent dose, metal ion concentrations and medium
temperature. Reduction in particle size increased the biosorption
capacity. Langmuir and Freundlich isotherm
models were applied to biosorption data to determine the
biosorption characteristics. An optimum biosorption
capacity (57.75 mg/g) was achieved with pH 4.0, particle
size 0.255 mm, biosorbent dose 0.5 g/100 mL and initial
uranium(VI) concentration of 100 mg/L. Uranium(VI)
removal by
Eucalyptus citriodora distillation sludge was
rapid, the equilibrium was established within 60 min and
pseudo-second-order model was found to fit with the
experimental data. The biosorption process decreased with
an increase in the temperature indicating its exothermic
nature. Pretreatments of biomass with different reagents
affected its biosorption capacity. A significant increase
(34 %) in biosorption capacity (83.25 mg/g) was observed
with benzene treatment. Fourier-transform infra-red studies
showed the involvement of carbonyl, carboxyl and amide
groups in the biosorption process. The results indicated that
sulfuric acid had the best effects as an eluent showing
93.24 % desorption capacity.