Synthesis and adsorption application of succinyl-grafted chitosan for the simultaneous removal of zinc and cationic dye from binary hazardous mixtures

In this work, a grafted (with carboxylic groups) chitosan material was synthesized and the adsorption mechanism of a basic dye (Remarcyl Red TGL denoted as CR) and a heavy metal (Zn) was investigated both in single-component and binary solutions. The reaction of succinic anhydride (SUC) with chitosan (CS) inserted a large number of carboxylic groups and the final chitosan-grafted material (abbreviated as CSUC) presented improved adsorption properties. A common phenomenon in the wastewater treatment science is the simultaneous existence of different-type pollutants (dyes, heavy metals etc.). The adsorption behavior of the material prepared (CSUC) was tested as multi-adsorbent for the simultaneous removal of Zn and CR from simulated wastewaters. CSUC was characterized using various techniques as SEM, XRD, and TGA, while the variety of adsorption interactions dominated in different pH-conditions (electrostatic forces, hydrogen bonding, chelation etc.) were confirmed with FTIR spectroscopy. The calculation of adsorption rate and maximum adsorption capacity were done using kinetic tests (pseudo-second order equation) and isotherms curves (Langmuir-Freundlich model), respectively. The antagonistic adsorption of CR or/and Zn was confirmed with selectivity experiments in binary mixtures. The reuse of this super-adsorbent was also proved with a series of 40 cycles of sequential adsorption and desorption modules. (C) 2014 Elsevier B.V. All rights reserved.