Decaying leaves have been proven capable of partially removing lead
from polluted water. Several factors affecting the removal process have
been studied. These include the concentration of lead ions,
concentration of leaves, drying leaves, degree of crushing of leaves,
leaf extracts, pH, agitation and presence of competing and of complexing
agents. The relative capability of some common types of leaves for the
removal of lead from water has been studied.
The release of lead
from leaves saturated with lead ions has been studied under the effect
of varying pH, addition of competing ions and the addition of complexing
agents.
The results of the present work indicate
that the interaction between lead ions and leaves is mainly an
adsorption process and fit the Freundlich adsorption isotherm whose
parameters have also been calculated. A fractional order of reaction
(0.7) has been determined for the reaction between lead ions and leaves
using two methods of evaluation. A mechanism in which film diffusion
being the most probable limiting step has been suggested.