Novel Polyethyleneimine/κ-Carrageenan Composite from Facile One-Step Fabrication for the Removal of Copper Ion from Aqueous Solution

In this work, a novel PEI/CG composite was fabricated via a facile one-step strategy at ambient conditions using biodegradable and highly absorbent κ-carrageenan (CG) as a matrix, polyethyleneimine (PEI) as a functional component and poly(ethylene glycol) diglycidyl ether (PGDE) for cross-linking PEI/CG. Systematic investigations were carried out to determine the optimal PEI/CG mass ratio, PGDE/PEI mass ratio and the total concentration of CG and PEI in CG/PEI/PGDE/5 wt% NaOH solution. Batch adsorption experiments have been achieved to investigate the effects of different parameters including solution pH, adsorbent dose, initial Cu2+ concentration, solution temperature and contact time on the adsorption performance of the composite towards Cu2+. Interestingly, the PEI/CG composite showed efficient Cu2+ adsorption performance. Furthermore, adsorption kinetics, thermodynamics and isotherms have also been investigated to reveal Cu2+ adsorption behavior and mechanism by the composite during the Cu2+ adsorption process. In addition, the PEI/CG composite after Cu2+ adsorption was also investigated with FT-IR and EDS technique to estimate adsorbed Cu2+ onto the composite. This work opened up new horizons for the fabrication of novel PEI composite with practical application using a facile one-step fabrication strategy.