Synthesis and Application of a Novel Sorbent (Tannic Acid-Grafted-Polyethyleneimine Encapsulated in Alginate Beads) for Heavy Metal Removal

Abstract

A sorbent was produced by chemical modification (tannic acid grafting) of polyethylenimine (PEI) and encapsulation in alginate gel beads. The sorbent was characterized by SEM-EDX and FTIR analyses before being used for the sorption of Cu(II), Zn(II) and Ni(II). The influence of pH was tested and sorption isotherms have been determined: the Langmuir equation fits well experimental data; for Cu(II), the bi-site Langmuir equation was preferred. Metal sorption capacity exceeds 1 mmol metal g⁻¹ and amine groups (with hydroxyl groups of tannic acid or carboxylic groups of alginate) contribute to metal binding. The pseudo second-order rate equation fits kinetic profiles well.

Keywords:

• heavy metal
• polyethylenimine
• tannic acid
• heavy metal
• sorption isotherm
• pH effect
• uptake kinetics
• diffusion
• encapsulation

ACKNOWLEDGEMENTS

Authors thank Jean-Marie Taulemesse for SEM and SEM-EDX analysis.

Additional information

Funding

This work is part of EU research project (BIOMETAL-DEMO). The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) managed by REA-Research Executive Agency (http://ec.europa.eu/research/rea) under grant agreement nº 619101.