Water purification through removal of toxic dyes using novel GO-grafted magnetic polyvinyl acetate: Kinetics, isotherms and thermodynamic studies

Wastewater pollution has been a significant environmental concern in recent decades, largely due to the substantial increase in the use of chemicals and dyes across various industrial sectors. The present study reports a facile co-precipitation method for synthesizing magnetized polyvinyl acetate (MPVA) and magnetized polyvinyl acetate blended with graphene oxide (MPVA-GO). A comparative assessment of their efficiency in removing methylene blue dye from wastewater has been performed. Numerous analytical characterisation techniques, such as FT-IR, XRD, FE-SEM, HRTEM, EDX, and AFM have been adopted to examine the morphological features and to determine the structural properties of these nanocomposites. Results of batch adsorption studies demonstrated a superior uptake potential of MPVA-GO. Interestingly, the pseudo-second-order model was found to most accurately describe the adsorption kinetic behaviour of both materials. Among the evaluated isotherm models—Langmuir, Freundlich, and Temkin—the adsorption behaviour of MPVA was best described by the Langmuir model, while the Temkin isotherm provided the most accurate representation of the adsorption equilibrium for the MPVA–GO adsorbent. Furthermore, thermodynamics studies indicate a greater ΔG°, ΔS°, and ΔH° values for MPVA-GO which draws conclusion to the results that MPVA-GO is a more efficient adsorbent toward cationic dyes with a more thermodynamically favoured adsorption process.