Enhanced application of modified clinoptilolite for efficient treatment of wastewater contaminated with toxic ions

Global water quality is increasingly compromised by the interplay of inadequate management, climate change, and escalating industrialization, leading to higher concentrations of toxic pollutants in available water resources. In the meantime, natural zeolites are recognized for their cost-effective potential in purifying polluted water. This study reports the development of a novel, highly effective adsorbent by applying a combined thermal and alkaline-ultrasonic treatment to natural clinoptilolite zeolite, which resulted in a 35% increase in mercury ion adsorption capacity compared to the raw material (achieving 95%removal efficiency). Furthermore, the modified zeolite maintained stable mercury ion adsorption through seven reuses. Characterization of the zeolite was conducted using several advanced techniques, including Field-Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX), and BET surface area analysis. The results of kinetic investigations demonstrated that the mechanism by which modified zeolite captures mercury ions from solution is consistent with the pseudo-second-order kinetic model. In addition, the equilibrium adsorption data were optimally elucidated by the Langmuir isotherm model, presenting a superior congruence when juxtaposed with the Freundlich isotherm.