Development of a bio-functional nanocomposite adsorbent for enhanced dye removal from aqueous media

Abstract

Untreated dye discharge into water bodies poses significant risks to aquatic life, human health and the environment. The widespread use of dyes in industrial processes has raised concerns among environmental activists and the public about the potential harm of dye effluents to ecosystems. Dye-based wastewater treatment has become increasingly important due to the rising contamination from industries such as food, pharmaceuticals and textiles. The primary objectives of the current investigation were to use gum arabic as a self-template for the in situ production of zinc oxide nanoparticles (ZnO NPs) optimized with bentonite, and to employ the resulting nanocomposite as a potential adsorbent for extracting synthetic dyes from aqueous solutions. The removal of methylene blue (MB) from aqueous solution has been accomplished using the gum arabic/zinc oxide/bentonite adsorbent. The specific adsorption properties of Ga/ZnO/bent was examined using adsorption kinetics and isotherms. The effectiveness of dye adsorption on a Ga/ZnO/bent has been examined using several factors, including temperature, pH, contact duration and concentration. The adsorption experiment was conducted by varying the temperature from room temperature to 60 °C, using a constant adsorbent dose of 6 g in 50 mL of a 100 ppm dye solution across different time intervals (5, 10, 15, 20, and 25 minutes). The optimal adsorption temperature was determined to be 60 °C, at which the hydrogel beads demonstrated an impressive removal efficiency of 98.37 ± 0.4%, indicating highly effective performance under elevated thermal conditions. The chemical oxygen demand (COD) of the 100 ppm MB-treated solution was 92.32 mg L⁻¹, and the mineralization efficiency was 80.14%. Beyond wastewater treatment, the Ga/ZnO/bent composite hydrogel beads hold great promise in biomedical applications such as antimicrobial wound dressings and drug delivery systems, in agriculture as slow-release micronutrient carriers, in active food packaging for enhanced shelf life, and in biosensing platforms for environmental and health monitoring, demonstrating their potential as a sustainable, multifunctional material for advanced technological applications.