Adsorption of Zn (II) Ions from Aqueous Solutions by Novel Adsorbent: Ngella sativa Seeds

Ngella sativa seeds, an agriculture material was used for the adsorption of Zn (II) ions from aqueous solutions. The Ngella sativa seeds were extracted with diethyl ether and dried in oven at 105 degrees C, burned at 500 degrees C for one hour. The adsorption capacity of the adsorbent was studied using batch adsorption technique at different conditions such as initial pH of adsorbate, contact time between adsorbent and adsorbate and initial concentration of adsorbate. Two kinetic models were applied include first-order and pseudo second-order. It was found that, the present work is follows the pseudo second-order. High adsorption capacity was observed at initial pH of 4. The adsorption capacity was reached equilibrium after 90 minute and at adsorbate initial concentration of 764 mg/l. The Freundlich adsorption model fits well when compared to the Langmuir model. The maximum adsorption capacity of this novel adsorbent was found to be 93 mg/g at temperature 30 degrees C. Two kinetic models such as first-order and pseudo second-order were tested, in order to study the mechanism of the adsorption. (C) 2013 The Authors. Published by Elsevier B.V.