<p>In this study, an LDH core–shell nanocomposite (NiAlFe-LDH@PS) was successfully prepared using NiAlFe-LDH as a core and coated with polystyrene (PS) nanoparticles via the coprecipitation method with a PS/LDH ratio of 2:1. PS nanoparticles were synthesized by recycling Styrofoam waste to produce styrene, a monomer for PS nanoparticle preparation. The prepared NiAlFe-LDH@PS was characterized by Transmission Electron Microscopy (TEM), X-ray diffraction patterns (XRD), Scanning Electron Microscopy/energy-dispersive X-ray spectroscopy (SED/EDX), Brunauer–Emmett–Teller analysis (BET), and Fourier-transform-infrared-spectroscopy (FTIR) analysis for structural morphology, elemental components, surface area, and pore morphology. Then, it is subsequently used as an innovative adsorbent for the elimination of Pb²⁺ ions from an aqueous solution. The maximum adsorption efficiency (99.7%) was achieved under the optimal conditions: pH 6, NiAlFe-LDH@PS dosage of 0.15g/100 mL of solution, agitation speed of 150 rpm, initial Pb²⁺ concentration of 75 mg/L, and a contact time of 75 min. The data fitted well with the Langmuir isotherm model, having a maximum adsorption capacity of 177.305 mg/g. The pseudo-second-order model accurately described the adsorption kinetics, with a correlation coefficient of 0.9947, indicating that external mass transfer and intra-particle diffusion control the adsorption mechanism. NiAlFe-LDH@PS exhibited significant reusability, with an efficiency of 42.37% after six regeneration cycles. Finally, this research demonstrates the significance of NiAlFe-LDH@PS as a superior adsorbent for sequestrating Pb²⁺ ions from an aqueous solution compared to other adsorbents used for the same purpose. The novelty of NiAlFe-LDH@PS nanocomposite lies in its cost-effective preparation from local waste materials, while maintaining high reliability in repeated cycles and superior cadmium removal performance compared to conventional adsorbents.</p>