In Situ Polymerization of Polyaniline on Natural Fibers for Effective Lead Ion Removal from Aqueous Solutions

The contamination of water with heavy metals, particularly lead (Pb² ⁺), has become a critical environmental and public health issue due to increasing industrialization and urbanization. Lead pollution has contributed to severe health problems, impacting over 10,000 people in recent years. In response to this growing concern, a composite material, PANI@NF, is developed by integrating polyaniline (PANI) with agrowaste fibers from date palm leaves, palm leaves, and korai grass. Among the tested composites, PANI@P20% demonstrates outstanding performance, achieving 96.2% lead removal and a sorption capacity of 24.1 mg g^-1 under optimal conditions (pH 6.0, 0.01 g adsorbent, 50 ppm Pb² ⁺, 298 K). The adsorption process for PANI@P20% follows a pseudo-second-order kinetic model and conforms well to the Freundlich isotherm, indicating multilayer adsorption on heterogeneous surfaces. Zeta potential analysis further confirms favorable surface charge interactions at pH 6.0. Additionally, this composite exhibits excellent reusability, maintaining high efficiency over eight adsorption-desorption cycles. This work underscores the potential of using low-cost, biodegradable natural fibers as sustainable adsorbents for effective lead removal, offering a promising solution for water treatment and environmental preservation.