Abstract:
Recent studies have shown that spent bleaching earth (SBE)
, a clayey waste from edible oil refineries,
could be used to remove Cu from aqueous solutions. Th
is could result in copper-laden material whose continual
disposal
into the environment may lead to bioaccumulation of toxic metal ions in the ecosystems. To asses
s
the
reversib
ility of copper uptake by spent bleaching earth, the kinetics of copper recovery from regenerate
d
spent
bleachin
g earth (RSBE) was studied on a batch basis in
H
SO
, and CaCl
. The acid showed superio
r
2
4
2
desorptio
n
efficiency than competitive effects of Ca
ions. The initial solid-phase Cu concentration an
d
2+
desorption
re
sident time were most important factors affecting copper release from RSBE. Up to 80% coppe
r
recovery
was realized
in 1-hour agitation period but longer contact time reduced the fraction of metal recovery
from
the adsorbent. The desorption process was consistent with the parabolic diffusion kinetics in bot
h
deso
rbants
although it was also correlated to the first order and second order models in
H
SO
and to th
e
2
4
modified Freundlich model in CaCl
respectively