Enhancing sustainability through optimized adsorption using a novel Klason-lignin-based biosorbent derived from sugar-palm fruit shells for efficient removal of Pb(II) and Cd(II)

• A novel application of Klason lignin from sugar palm fruit shells for heavy metal adsorption. • KLSPFS demonstrated high adsorption efficiency • Process parameter optimization performed using the Box-Behnken design • KLSPFS biosorbent contributing to waste management and circular economy This study investigates the isolation and application of a Klason-lignin-based biosorbent derived from sugar palm fruit shell (SPFS) waste for the adsorption of Pb(II) and Cd(II) from toxic wastewater. The SPFS waste, rich in lignocellulose, underwent pretreatment to extract lignin-containing functional groups suitable for metal ion adsorption. The biosorbent's morphology bfefore and after adsorption was analyzed. Adsorption effectiveness was evaluated through isotherm and kinetic models, with optimal conditions determined using Box-Behnken Design and Response Surface Methodology. Maximum adsorption capacities of 31.35 mg/g for Pb(II) and 12.5 mg/g for Cd(II) were achieved. Optimal conditions, based on Box-Behnken design, were 116.535 minutes, 60 mg/L concentration, and 0.5 g adsorbent mass, resulting in adsorption efficiencies of 94.48% and 60.98% for Pb(II) and Cd(II), respectively. This research demonstrates the potential of Klason lignin from sugar palm fruit shell (KLSPFS) as an effective biosorbent for Pb(II) and Cd(II) removal, contributing to sustainable development goals 3, 6, and 12 by promoting efficient recycling technologies for improved health, water quality, and waste reduction.