Optimization of Pb (II) and Cd (II) adsorption onto ZnO nanoflowers using central composite design: isotherms and kinetics modelling

By Navish Kataria, V. Garg. Journal of Molecular Liquids, 2018

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Abstract This study focused to optimization and screening of parameters for the adsorption of Cd (II) and Pb (II) onto ZnO nanoflowers. These were synthesized by low temperature hydrothermal methods. The surface properties of ZnO nanoflowers, before and after metal adsorption were characterized by FTIR, FESEM and EDX spectra. The adsorption parameters were optimized using central composites design. Adsorption behaviour and metals–adsorbent interaction was evaluated using batch mode experiments and isothermal models. Maximum adsorption capacity of ZnO nanoflowers was 71.5 mg/g and 115 mg/g for Cd (II) and Pb (II), respectively. In isotherms studies, Freundlich model is best fitted to metal adsorption data that indicated multilayer adsorption of Cd (II) and Pb (II) onto ZnO. The rate mechanism of metals ions adsorption was well explained by pseudo-second order models. The Adsorption efficiency of ZnO nanoflowers was analysed in spiked ground water sample also. The reusability of ZnO nanoflowers was also explored upto three cycles.

Subfields: Industrial and Manufacturing Engineering, Organic Chemistry, Water Science and Technology

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