Incorporation of copper ion promoted adsorption of anionic dye (Acid Yellow 36) by acrolein-crosslinked polyethyleneimine/chitosan hydrogel: Adsorption, dynamics, and mechanisms

In this study, a novel adsorbent, A-PEI/CS-Cu 2+ , was developed by crosslinking polyethyleneimine/chitosan hydrogel with acrolein and loading it with copper ions . The adsorption process of A-PEI/CS-Cu 2+ on the anionic dye acid yellow 36 (AY36) was investigated by kinetic, isothermal and thermodynamic modeling . It was noteworthy that A-PEI/CS-Cu 2+ exhibited rapid adsorption with a 90 % removal rate achieved within just 5 min, which was much faster than the adsorption rate of A-PEI/CS without load of copper ions and showed its potential for rapid adsorption applications. The maximum adsorption capacity for AY36 could reach up to 3114 mg g −1 . In addition, the high concentration of saline wastewater was found to have almost no effect on the adsorption reaction in the salt effect test experiment. In five desorption-regeneration cycle experiments, the sample exhibited good recyclability and regeneration performance. The driving force of the adsorption process mainly originated from the electrostatic interaction , hydrogen bonding , and intermolecular interaction, in which the addition of copper ions led to the enhancement of the electrostatic interaction and chelation between A-PEI/CS-Cu 2+ and AY36. Overall, the findings suggest the excellent potential of A-PEI/CS-Cu 2+ for rapid and efficient adsorption, as well as its suitability for practical applications in wastewater treatment .