Magnetic Activated Carbon Functionalized with Polyaniline for Efficient Pb (II) Adsorption from Aqueous Solutions

Lead (Pb) contamination in water poses a significant threat to both human health and the environment as it is toxic even at very minimal concentrations. In the scope of this study, a novel magnetic composite material, AC/Fe3O4/PANI-SDS, was synthesized to efficiently eliminate Pb2+ ions from polluted water. Each component of the composite has a significant impact: the activated carbon provides a large surface area for adsorption, the magnetic iron oxide (Fe3O4) allows easy magnetic recovery from water systems using a magnet, and the polyaniline (PANI) and sodium dodecyl sulfate (SDS) improve the capability of the material to attract and hold onto Pb2+ ions. To assess the surface, magnetic, and structural properties of the prepared material, several characterization techniques were applied, such as FTIR, XRD, SEM-EDS, BET analysis, VSM, and zeta potential measurements. These tests confirmed that the composite has the right structure and functional groups to perform as a capable and efficient adsorbent. Batch adsorption studies were used to evaluate the effects of pH, interaction time, initial Pb2+ ion concentration, and temperature on removal efficiency. The findings highlight the composite’s remarkable adsorption efficiency after 220 min under optimal conditions, specifically at pH 6. Adsorption kinetic studies demonstrated strong agreement with the pseudo-second-order model, while isotherm analysis showed that the Langmuir model provided the highest correlation coefficient within the investigated concentration range. This fitting suggested apparent Langmuir-type adsorption behavior, with a maximum adsorption capacity of 348.39 mg/g. Thermodynamic assessment demonstrated that the elimination of Pb2+ ions is an endothermic and spontaneous process. In addition, the composite can be reused and recycled repeatedly without significantly reducing its effectiveness, offering an economical and ecologically sustainable approach. The findings of this research highlight the potential of the AC/Fe3O4/PANI-SDS composite as a new, efficient, and eco-friendly adsorbent for the elimination of Pb2+ ions from solutions. In real-world applications, its high capacity for adsorption, ease of separation, and reusability make it a promising treatment for heavy metal contamination.