Removal of hexavalent chromium ions
[Cr(VI)] from aqueous solutions by adsorbents prepared
from barks of
Acacia albida
of Fabaceae family and leaves
of
Euclea schimperi of Ebenaceae family has been studied
by batch adsorption technique. Double-beam UV–visible
spectrophotometer was used to monitor the concentration
of Cr(VI). The influence of contact time, initial chromium
ion concentration, pH and adsorbent dose on the efficiency
of adsorption process was studied. Among the studied
parameters, pH was found to be the most influential. At the
optimum pH (pH 2), 98.47 and 97.39 % removal of Cr(VI)
was achieved using the adsorbents prepared from barks of
A. albida and leaves of
E. schimperi, respectively. After
determining the optimal conditions for maximum adsorption,
the applicability of the biosorbents was tested on real
samples. The results indicate that these adsorbents can be
employed as low-cost alternatives to commercial adsorbents
for the removal of Cr(VI) from effluents. Adsorption
isotherms and kinetic parameters were also studied. The
results showed that the adsorption of Cr(VI) by these
adsorbents follow Langmuir adsorption isotherm. The
kinetics of the adsorption process follows the pseudo-second-order kinetic model.
