Efficient Removal of Aqueous Copper (II) Ions Using EDTA-Modified Graphene Oxide: An Adsorption Study

Graphene oxide has drawn attention globally as it emerged as a promising adsorbent material with enhanced adsorption of environmental pollutants due to its eco-friendly attributes, high surface area, and cost-effectiveness for mass production. This economical solution is a promising and potentially transformative approach to heavy metal removal, contributing to a cleaner and more sustainable future. In this study, unmodified and modified graphene oxide were examined for the removal of copper (II) ions in an aqueous solution. Modified Hummer’s method was utilized to synthesize the graphene oxide. The synthesized graphene oxide was then modified with N- trimethoxysilylpropylethylenediaminetriaceticacid (EDTA-silane), resulting in EDTA-modified graphene oxide (EGO). Batch adsorption tests were done for both adsorbents in order to determine the effects of various factors, such as pH, adsorbent dosage, and contact time. Additionally, in order to describe the adsorption behavior of the adsorption system, it was further fitted to isotherm and kinetic adsorption models. Results of adsorption study showed optimum adsorption for copper (II) ions was achieved at pH = 7, contact time = 45 min, and adsorbent dosage of 5 mg and 4 mg of unmodified graphene oxide (GO) and modified graphene oxide (EGO), respectively. The fundamental mechanism of both adsorbents was best explained by Langmuir isotherm model and the pseudo-second-order model, indicating that the adsorption system followed chemisorption. The adsorption capacity and maximum removal of copper (II) ions was 672.22 mg/g and 78.41% for GO, and 729.11 mg/g and 89.94% for EGO. The latter suggested that graphene oxide treated with EDTA-silane (EGO) has the higher capacity to adsorb copper (II) ions.