A New Approach of Complexing Polymers Used for the Removal of Cu Ions.

This study presents two modified polymers for Cu ion removal from aqueous media. Shredded maize stalk (MC) and a strong-base anionic resin (SAX) were modified with indigo carmine (IC) in order to obtain two different complexing polymers, i.e., IC-MC and SAX-IC. Initially, the complex reaction between IC and Cu in the solution was studied. Additionally, the complex formation Cu-IC in liquid solutions was evaluated at different pH ranges of 1.5, 4.0, 6.0, 8.0, and 10.0, respectively. For Cu ions, adsorption onto the IC-MC and IC-SAX batch experiments were conducted. The contact time for evaluating the optimum adsorption for Cu ions on the complexing materials was established at 1 h. Efficient Cu ion adsorption on the IC-MC and SAX-IC at pH = 10 was achieved. The adsorption of Cu ions depends on the quantity of IC retained on MC and SAX. At 2.63 mg IC/g MC(S4) and 22 mg IC/g SAX(SR2), a high amount of Cu ion adsorption was reported. The highest adsorption capacity () of IC-MC was obtained at 0.73 mg/g, and for IC-SAX, it was attained at 10.8 mg/g. Reusability experiments were performed using the HCl (0.5 M) solution. High regeneration and reusability studies of IC-MC and IC-SAX were confirmed, suggesting that they can be used many times to remove Cu ions from aqueous matrices. Therefore, the development of complexing materials could be suitable for Cu ion removal from wastewater.