Synthesis and characterization of a novel EDTA-based adsorbent for the removal of Cu(II) ions from aqueous medium

The study aims to explore the possibility of synthesizing EDTA-based adsorbents by an alternative method and the heavy metal adsorption characteristics of these products in the synthesized aqueous solutions of Cu(II) ions. For this purpose, an alternative anhydride (C 24 H 24 N 2 O 10 ) of EDTA dianhydride was prepared directly from the reaction of disodium ethylenediaminetetraacetic acid (Na 2 -H 2 EDTA) and benzoyl chloride (C 6 H 5 -COCl), which was then reacted with methanol to synthesize methyl diester of EDTA (C 12 H 20 N 2 O 8 ). The synthesized methyl diester of EDTA was characterized by using the elemental analysis, XRD, SEM, TEM, 1 H NMR, 13 C NMR, DEPT-135 NMR, FTIR, UV-visible spectroscopy, and EDX analyses. Batch techniques were used to investigate the adsorption of Cu(II) by the synthesized adsorbent. To optimize the adsorption process, the effects of various factors, such as pH, contact time, and the concentration of Cu(II) solutions were studied. Based on the Langmuir model, the maximum adsorption capacity was found to be 212.8 mg g -1 at the optimized pH value of 6 and contact time 30 minutes. The equilibrium experimental data were found to be the best fit to the pseudo-second-order kinetic and the Langmuir isotherm models. The negative values of free energy and enthalpy changes, and the positive value of entropy change suggested that the adsorption process was spontaneous, exothermic, and irreversible. Overall, the synthesized product could be a promising adsorbent for the removal of Cu(II) from wastewater due to its simple synthesis process and considerable adsorption properties. • Explored the simple and fast synthesis method of EDTA-based absorbents • Synthesized adsorbent and its metal complex are water insoluble • The removal of Cu(II) was found to be 98% • The highest adsorption capacity was estimated to be 212.8 mg g -1 . • The pseudo-second-order kinetic and the Langmuir isotherm models were fitted well.