Optimized Synthesis of Graphene Oxide-Based Hydrogel Composite Beads for Efficient Methyl Orange Removal from Aqueous Solutions

Abstract:

Synthetic dyes such as methyl orange (MO) are persistent water pollutants that pose serious environmental and health hazards due to their toxicity and resistance to biodegradation. Developing efficient, sustainable, and reusable adsorbents for dye removal remains a major challenge in wastewater treatment. This study presents the design and optimization of chitosan/polyethyleneimine/graphene oxide (CS/PEI/GO) hydrogel nanocomposite beads synthesized through controlled cross-linking with glutaraldehyde (GLA) for enhanced adsorption of MO from aqueous solutions. A Box–Behnken experimental design coupled with response surface methodology (RSM) was employed to evaluate the effects of PEI, GO, and GLA concentrations on adsorption capacity. Statistical analysis confirmed the high significance of the cubic model (F = 38.34, p = 0.0001) with a non-significant lack of fit, validating its strong predictive reliability. PEI concentration had the most pronounced effect, providing protonated amine sites for electrostatic interaction with the anionic dye, while GO increased surface area and provided oxygen-containing groups that enhanced hydrogen bonding and π–π interactions. GLA served as a cross-linker to stabilize the hydrogel structure without deactivating active sites. The optimized composition (2.0% PEI, 900 ppm GO, and 2.5% GLA) achieved a predicted adsorption capacity of 23.16 ± 1.05 mg/g, which closely matched the experimentally obtained value of 23.31 ± 1.19 mg/g, with only 2.2% deviation. These findings confirm that the CS/PEI/GO hydrogel nanocomposite provides a balanced integration of structural stability, functional site availability, and high adsorption efficiency, demonstrating its potential as a scalable, eco-friendly material for advanced dye removal and sustainable wastewater treatment.

• Periodical: Nano Hybrids and Composites (Volume 51)
• Pages: 33-43
• DOI: https://doi.org/10.4028/p-00jxZH
• Online since: May 2026
• Authors: Edgar Clyde R. Lopez*
• Keywords: Adsorption, Chitosan, Graphene Oxide, Hydrogel, Methyl Orange, Polyethyleneimine

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