Equilibrium, Kinetic and Thermodynamic Studies of theAdsorption of Heavy Metals from Aqueous Solution by ThermallyTreated Quail Eggshell

Background and Objective: Nowadays, the contamination of water resources by heavy metals has resulted in serious health issues. Themetals in their elemental as well as chemically combined form are toxic, non-degradable and persistence in nature. Thus, there is needto develop a simple, efficient and economical method for removing dissolved heavy metals from water/wastewater. In the presentstudy, it was aimed to prepare a new adsorbent from agricultural waste in order to remove Cu2+ and Zn2+ from aqueous solution.Materials and Methods: Calcium oxide (CaO) based material was prepared from quail eggshell, characterized and used as adsorbent forthe removal of Cu2+ and Zn2+ from aqueous solution. Calcined quail eggshell at 900EC was studied and exhibited high adsorption capacity.The effects of variables affecting the adsorption process, contact time, adsorbent dosage, temperature and initial heavy metalsconcentration were investigated at fixed pH of 4.5. Results: At contact time of 30 min, adsorbent dosage of 1.5 g, temperature of 35ECand initial Cu2+ and Zn2+ concentration of 150 mg LG1, the maximum heavy metals uptake could be achieved. Based on the value ofcorrelation coefficient, the experimental results for Cu2+ best fitted the Langmuir isotherm model with monolayer adsorption capacityof 13.49 mg gG1, while Freundlich isotherm model was best fitted to the experimental results for the Zn2+ adsorption. The kinetics andthermodynamic behaviours of the adsorption process were also investigated. Conclusion: The obtained results showed that theexperimental data were in good agreement with pseudo-second-order kinetic model. The results from thermodynamic analysis revealedthat the process is spontaneous and endothermi