الفهرس 
titelOnly 14 pages are availabe for public view
 |  | from | 192 |  |  |
| | | from | 192 | | |
Abstract
The ability of natural biosorbents for removing heavy metal ions were investigated by studying the effect of nano sized Delonix regia and Moringa oleifera on adsorption of Cd2+ and Pb2+ ions from aqueous solution. The investigated biosorbents (Delonix regia and Moringa oleifera) were characterized by FT-IR, SEM, TEM, XRD and EDS techniques. The influence of pH, temperature, adsorbent dosage, contact time and initial metal ion concentration on adsorption process were investigated. The maximum biosorption capacities (qm) of Cd2+ and Pb2+ by Delonix regia and Moringa oleifera were 37.23, 40.54, 43.62 and 37.91 mg/g, respectively. The lowest biosorptions for Cd2+and Pb2+ ions were observed at pH 2.0 by the investigated biosorbents. The highest biosorption was observed for Cd2+ ions on Delonix regia and Moringa oleifera at pH 4.0, 5.0, respectively. The highest biosorption for Pb2+ ions was observed at pH 5 by the investigated biosorbents. The optimum contact time for the adsorption process was found to be at 60 minutes. The amount of metal ions adsorbed increases with increasing the adsorbent dosage. Moreover, biosorption capacity (qe) and removal efficiency of Cd2+ and Pb2+ions solutions increases as temperature increases. FT-IR data indicated that the adsorption of metal ions occurs on the surface of Delonix regia and Moringa oleifera as the main functional groups that are responsible for metal ions binding are involved in the process. XRD pattern of the powder indicating the presence of a significant amount of amorphous material due to lignin in the biosorbents. SEM showed the morphological features and the surface morphology of the powders did not have regular, fixed size and shape. TEM analysis examined the particle size of the majority of particles and was found to be 18, 30 nm for Delonix regia and Moringa oleifera, respectively. EDS analysis determined the