Synthesis and characterization of a novel Ca-alginate-biochar composite as efficient zinc (Zn²⁺) adsorbent: Thermodynamics, process design, mass transfer and isotherm modeling

ABSTRACT

In this present work, Ca-alginate-biochar adsorbent has been synthesized, characterized and tested its effectiveness in the removal of aqueous phase Zn²⁺ metal. The removal efficiency was studied under various physicochemical process parameters. External mass transfer model, intraparticle diffusion model and pseudo-first-order and pseudo-second-order models were used to fit the experimental Zn²⁺ adoption kinetic results and to identify the mechanism of adsorption. The desorption studies indicate the possibilities of ion-exchange and physical–chemical adsorption of Zn^2+. The adsorption was best described by Langmuir isotherm model. Thermodynamic parameters suggested that the adsorption process becomes spontaneous, endothermic and irreversible in nature.

Graphical Abstract

KEYWORDS:

• Ca-alginate-biochar composite
• adsorption mass transfer model
• metal ions
• isotherm

Acknowledgments

The authors acknowledge the Department of Chemical Engineering, IIT Kharagpur, India and Curtin University, Australia for providing all research instruments and financial support to carry out this study. The authors are highly thankful to the MMF laboratory of John de Laeter Centre of Curtin University for the SEM imaging and XRD analysis.

Additional information

Funding

The authors acknowledge the Department of Chemical Engineering, IIT Kharagpur, India and Curtin University, Australia for providing all research instruments and financial support to carry out this study.