Kinetics Studies on the Process of Zn Removal from Wastewater Using Ultrasonically Activated Sorbents

Heavy metals pollution in industrial wastewater is a great environmental challenge. Several techniques and materials have been recently proposed in order to overcome this problem, such as the adsorption process; however, in order to be competitive, new improved low-cost materials must be proposed or developed. In the present work, the remediation of Zn-contaminated water using fly ash and Tonsil was studied. Both materials are considered low-cost sorbents since they are a byproduct of an industrial process, or locally abundant in nature. To increase the Zn uptake, the materials were activated by applying ultrasonic energy. It was found that the pH is an important parameter to be controlled since the larger sorption capacity occurred at pH = 4. Also, the materials activated with ultrasound were able to adsorb greater Zn quantities at the studied experimental conditions. Finally, the kinetics of the adsorption process was analyzed, and several mathematical models were proposed to simulate the experimental data. After making some statistical discrimination, the Lagergren model was selected to represent the sorption of Zn on the different materials studied.