Acacia Tortilis Seeds as a Green Chemistry Adsorbent to Clean up the Water Media from Cadmium Cations

Abstract

 Abstract—The potential use of Acacia tortilies seeds as a new green chemistry adsorbent to reduce cadmium cations from water was evaluated through batch experiments. The Acacia tortilies seeds were characterized by determination of solubility in water and determination of surface area and pore volume as well as determination of cellulose content. The important parameters which affect the adsorption process, such as initial pH, contact time and contact temperatures were studied. The maximum adsorption capacity occurs at pH 3.4 after 2 hours. Two isotherm models include Langmuir and Freundlich were investigated. The maximum adsorption capacity obtained were 706, 807and 1004 mg/g at 293, 303 and 323 K, respectively. Experimental data were also performed to the first-order, pseudo-second order and intra-particle diffusion kinetic models. The results indicated that the adsorption of cadmium cations onto Acacia tortilies seeds followed well second-order kinetics. Thermodynamic parameters,  Go ,  Ho and  S o indicated the cadmium cations sorption to be endothermic and spontaneous with increase randomness at solid-solution interface. The adsorption mechanism of cadmium cations onto Acacia tortilies seeds was interpreted. A comparison between adsorption capacity of Acacia tortilies seeds and adsorption capacities of other low cost adsorbents were presented. It was found that, the adsorption capacity of Acacia tortilies seeds was higher than the adsorption capacities of all other low cost adsorbents indicated in this research.