Efficient removal of Pb2+ ions from water using sulfonated polyvinylidene fluoride; Synthesis and characterization of a novel cation exchange resin

• Sulfonated PVDF synthesized as a novel, thermally stable ion-exchange resin. • Achieved 95% Pb 2+ removal at 25 ppm under optimal pH 5-7 conditions. • Adsorption kinetics fit the pseudo-second-order model (R 2 = 0.9802). • Langmuir isotherm confirmed monolayer chemisorption with high capacity. • Resin shows enhanced hydrophilicity, strong recyclability, and high efficiency. Heavy metal contamination in aquatic systems represents a serious environmental and public health concern, necessitating the development of efficient and durable treatment materials. In this work, sulfonated polyvinylidene fluoride (S-PVDF) was successfully synthesized through sulfuric acid sulfonation and introduced as a novel ion exchange resin for the removal of Pb 2+ ions from water. Structural and functional modifications of the polymer were confirmed by FTIR, 1 H-NMR, TGA, and contact angle analysis, which collectively demonstrated the successful incorporation of -SO 3 H groups and enhanced hydrophilicity. Batch experiments achieved an adsorption capacity of 11.8 mg.g −1 (95% removal at 25 ppm) within 5 h under optimal pH 5-7, with equilibrium capacities of ∼38-39 mg.g −1 (83-86% removal). Column studies further demonstrated strong performance, achieving 90% efficiency at low flow rates and 81% at a bed height of 10 cm. Kinetic modeling revealed that the adsorption process followed the pseudo-second-order model (R 2 = 0.98), with a fitted capacity of 37.175 mg.g −1 , indicating chemisorption as the dominant mechanism. Equilibrium data fitted the Langmuir isotherm (R 2 = 0.99), with a maximum adsorption capacity of approximately 63.7 mg.g −1 , confirming monolayer adsorption on a uniform surface. These findings highlight S-PVDF as a thermally stable ion exchange material, offering a promising alternative to conventional resins for sustainable water purification applications.