The increasing discharge of heavy metals and toxic contaminants into aquatic environments has created an urgent need for efficient and sustainable water treatment technologies. Nanocomposite cation exchangers have emerged as promising materials due to their high surface area, excellent ion exchange capacity, improved mechanical strength, and enhanced chemical stability. In this study, a novel organic–inorganic nanocomposite cation exchanger was synthesized using a polymeric matrix combined with zirconium-based inorganic nanoparticles through a sol–gel precipitation method. The synthesized material was characterized using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Thermogravimetric Analysis (TGA) to investigate its structural, morphological, elemental, and thermal properties.

The ion exchange capacity of the prepared nanocomposite was evaluated by standard column methods, while its adsorption performance toward selected heavy metal ions, including Pb(II), Cd(II), Cu(II), Ni(II), and Zn(II), was investigated under batch adsorption conditions. The effects of pH, contact time, adsorbent dosage, initial metal ion concentration, and temperature on adsorption efficiency were systematically examined. The adsorption process was further interpreted using Langmuir and Freundlich isotherm models, whereas adsorption kinetics were analyzed using pseudo-first-order and pseudo-second-order kinetic models. The synthesized nanocomposite exhibited rapid adsorption kinetics, high selectivity toward divalent metal ions, excellent regeneration capability, and stable performance over repeated adsorption–desorption cycles.

The results demonstrate that the developed nanocomposite cation exchanger possesses superior adsorption efficiency and ion exchange capacity compared with conventional ion exchange materials. Its excellent physicochemical properties and reusability make it a promising candidate for industrial wastewater treatment, environmental remediation, metal ion recovery, and analytical preconcentration of trace metals. The study highlights the potential of nanocomposite cation exchangers as cost-effective and environmentally sustainable materials for advanced water purification technologies.