Utilization of Calligonum comosum as a New Adsorbent Material for Lead Ion Removal from Aqueous Solution

The quantities of heavy metals in surface and ground water are increased during the recent years due to industrial activities and the development of new technologies. The important of study of the different ways in which heavy metals can be destroyed from water lies in their toxicity and accumulation in living organisms. These heavy metals transfer to the living organisms via different ways such as skin and mouth and cause several health problems such as anemia, kidneys and liver diseases, brain damage, and ultimately death. For these reasons, it is very important to clean up water from heavy metal contamination.Lead is one of the most dangerous heavy metals, which is toxic even at trace level. It is accumulate in the food chain and can not be destroyed due to the difficulty of degradation. The nvironmental Protection Agency (EPA) reports that, the action level of lead in drinking water is 0.05 mg/l.Several methods were used to remove lead from water or west water such as ion exchange, precipitation, electrodialysis, membrane separations, solvent extraction, biological materials, and activated carbon. Agriculture materials or agriculture wastes such as cotton stalks, peanut hulls, palam tree, wood pulp, and onion skins also have been used as a low cost materials.Calligonum comosum will be use in this work as a novel bio-adsorbent material for removal of lead ions from aqueous solution by performing a batch adsorption technique. Different parameters such as pH, particle diameter, adsorbent concentration, contact time, mixing speed, temperature, initial concentration, and ionic strength were studied to optimize the condition of adsorption.Adsorption kinetics such as first-order reaction, second-order reaction and intra-particle diffusion models were investigated. Langmuir and Freundlich isotherms were applied to the equilibrium data. Thermodynamic parameters such as Δ G°, Δ H° and ΔS° were calculated according to the Langmuir constant kL. The obtained maximum adsorption capacity (Q max) from the Langmuir isotherm plots were 96.76, 98.16 and 108.74 mg/g at 293 K, 303 K and 323 K, respectively.