Removal of Astrazon Red Dye from Wastewater using Eggshell/Graphene Oxide Embed in (Gum Acacia/Acrylamide) Hydrogel Nanocomposites Synthesized by Gamma Irradiation

Abstract

AbstractThis research aimed to use a low-cost, environmentally friendly adsorbent to eliminate the cationic dye Astrazon red 6B (AR) from an aqueous system. For this rationale, a nanocomposite hydrogel made of (Gum Acacia/Acrylamide)-calcinated Eggshell/Graphene oxide (GA/AAm)-ES/GO was created using Gamma radiation-induced copolymerization and cross-linking. FT-IR, XRD, EDX mapping, SEM, TGA and TEM were used to investigate the structures and properties. The nanocomposites exhibited superior adsorption behavior towards AR. Because of the dual effect of ES and GO, mixing ES with GO in (GA/AAm)-ES/GO nanocomposite hydrogel improved its adsorption capability. It was obtained that the optimum initial pH was 9 and the equilibrium contact time was 480 min. The removal percentage was enhanced by increasing the initial dye concentration. A little removal effectiveness was observed by increasing the adsorbent weight from 5.0 to 10.0 g for each liter of the dye solution. The Langmuir isotherm was found to be more suitable for analyzing the adsorption isotherm the maximal monolayer dye adsorption capacity (qmax) was 313.3 mg/g. The pseudo-second-order adsorption kinetics fitted the data well, and the rate constant was predicted to be (0.108 10–3) g mg−1 min−1. ∆H° values are negative at all investigated initial concentrations for (GA/AAm)-ES and (GA/AAm)-ES/GO. The values of ∆S° are negative for (GA/AAm)-ES/GO, while values for (GA/AAm) and (GA/AAm)-ES are positive. ∆G° are negative values for all systems that refer to the spontaneity of the adsorption process. High efficiency was observed for (GA/AAm)-ES/GO up to three rounds of reuse, while a drop in efficiency of the fourth round to 58.78%. Graphical Abstract