Sustainable fabrication of arecanut waste-based polymer blend adsorbents for enhanced lead(ii) ion removal from water

Abstract

Heavy metal contamination in water systems leads to critical environmental and health challenges, necessitating sustainable remediation technologies. This study presents a unique approach utilising arecanut organic residue, an abundant agricultural waste, for the removal of lead from water. A bioadsorbent composite film was synthesised using chitosan–polyvinyl alcohol (PVA) incorporated with arecanut organic residue by solvent casting. The physicochemical properties of the films were characterised by XRD, FTIR, optical profilometry, BET surface area and SEM analyses. The adsorption efficiency of the synthesised films was tested by examining the removal of Pb(II) from water. The bioadsorbent films demonstrated a Pb(II) removal efficiency of 94.6% from 5 ppm solutions at pH 6 within 60 minutes at 70 °C using 0.5 g of the film. Optimisation studies revealed the critical role of functional group availability and film porosity of the polymer blends, along with experimental conditions that enhanced the adsorption capacity. Kinetic studies also confirmed the results obtained from the optimisation studies. The adsorption kinetics followed a pseudo-second-order model, and isotherm analysis confirmed Langmuir-type adsorption. The sustainable bioadsorbent exhibited good reusability, maintaining performance over multiple cycles.