Uptake of Cd and Pb from Aqueous Solutions Using Selected Tree Leaves Through Phytoremediation

Leaves of five selected plants Citrus limon (Rutaceae), Ceratonia siliqua L., Olea europaea (Oleaceae), Washingtonia filifera, and Myoporum (Myoporaceae) grown in Jordan were examined for removal of heavy metals (cadmium (Cd) and lead (Pb) ions) for aqueous solutions. Cd and Pb were analyzed by atomic absorption spectrometry. A pH S-2 acidometer was used for determining the acidity of leaves–solution systems. Results indicated that those plant leaves were efficient for removal of metals compared with the efficiency of activated carbon. Removal of a 5 mg/L aqueous metal solution of Cd and Pb was treated with 2.5 g of oven-dried plant in 50 mL deionized water. The metal removal was expressed as a function of time ranging between 0 and 192 h of contact time. The uptake of Cd and Pb by leaves of the plants was arranged in the following order: (i) for Cd, activated carbon > Olea europaea (Oleaceae) > Ceratonia siliqua L. > Washingtonia filifera > Citrus limon (Rutaceae) > Myoporum (Myoporaceae); (ii) for Pb, activated carbon > Olea europaea (Oleaceae) > Ceratonia siliqua L. > Washingtonia filifera > Citrus limon (Rutaceae) > Myoporum (Myoporaceae).