Chitosan Based Polymer Membrane Modified with CuO/Graphene Oxide Nanoparticles: Novel Synthesis, Characterization and Enhanced Methyl Orange Removal

This study developed a novel nanocomposite by blending Chitosan and Polyvinyl Alcohol (Ch/PVA) with 1% Copper Oxide nanoparticles (CuO NPs), cross-linked using tetraethyl orthosilicate (TEOS). Three Ch/PVA-based nanocomposites were synthesized using CuO, Graphene Oxide (GO), and a CuO&GO combination. The research aimed to assess the nanocomposites’ efficacy in removing methyl orange (MO) dye. The X-ray diffraction analysis revealed that the fabricated CuO NPs had a monoclinic structure with an average particle size of 16.35 nm. The distinctive bands at 3222 cm −1 for the Ch/PVA composite were confirmed by Fourier-transform infrared spectroscopy (FT-IR). Scanning Electron Microscopy (SEM) results confirmed the NPs were well distributed throughout the matrix and Thermal gravimetric analysis (TGA) verified the stability of chitosan till 350 °C. The sorption experiments with methyl orange dye were carried out under different pH (2–12), dye concentration (0.025–1.0 mML −1 ), contact time (0–60 min), and temperature (25–55 °C) to establish the adsorbent at the lab-scale. UV–vis results showed the maximum sorption capacity (72 mM/g) achieved within 10 min with 96% dye removal. The adsorption behavior of nanocomposites was attributed to a physicochemical and monolayer adsorption process. Thermodynamic studies at 328 K confirmed that the adsorption process was spontaneous with Δ G ° value − 4.2 KJmol −1 . Also, ΔH° and ΔS° were found to be 11.3 and 52.2 KJmol −1 for MO adsorption, respectively. This work paves a new route for developing biodegradable, nontoxic, cost-effective, eco-friendly, and highly efficient adsorbents capable of selectively removing and recycling anionic dyes from wastewater. Graphical Abstract