Efficiency of dry plant leaves (MULCH) for removal of lead, cadmium and copper from aqueous solutions

Mulch has been found to be capable of removing lead, cadmium and copper from aqueous solutions. The efficiency of this removal, at the optimal conditions, is close to the efficiency of removal using activated carbon. Several factors affecting the removal process have been studied. These include plant type, concentration of metal ions and method of drying leaves. The method of analysis used is the AAS. The efficiency of removal of lead by plant leaves was, in decreasing order: Eucalyptus camaludulensis L. approximate to Pinus halepensis L. > Thuja orientalis L. > Populus nigra L. > Phragmites australis L. > Anabasis syriaca L. The efficiency of removal of cadmium by plant leaves was, in decreasing order: Eucalyptus camaludulensis L. > Populus nigra L. > Anabasis syriaca L. similar to Thuja orientalis L. > Phragmites australis L. > Pinus halepensis L. The removal process of lead, cadmium and copper followed the Freundlich adsorption isotherm. Maximum removal efficiency by plant leaves was at ca pH7 for cadmium and at ca pH 5.4 for copper. Oven-dried leaves showed slightly higher removal efficiency of metal ions than naturally dried leaves.