Improving copper ions adsorption using Ca-modified NaY zeolite synthesized from calcined rice husk ash

In this study, NaY zeolite was fabricated from calcined rice husk ash using a hydrothermal method, followed by modification with calcium, which significantly enhanced its capacity to adsorb copper ions. Advanced analytical techniques confirmed the successful creation of Ca-modified NaY zeolite, which boasted a CaO/Al₂O₃ ratio of 1.0, a crystallization time of just 24 h, and an impressive crystallinity of 95%. This zeolite featured a microporous structure with a pore diameter of 1.139 nm and a specific surface area of 321.1 m²/g. The optimal conditions for copper ion adsorption were pinpointed to a pH of 4.0, an initial concentration of 50 mg/L, and a modest adsorbent mass of 0.1 g over a contact time of 60 min, achieving a remarkable maximum capacity of 75.18 mg/g. The kinetic and isotherm analyses revealed a reversible adsorption process characterized by uniform surface energy, enabling the adsorbent to facilitate multilayer adsorption through physical interactions. These compelling findings underscore the exciting potential of Ca-NaY zeolite derived from rice husk ash as a sustainable solution for effectively removing metal ions from wastewater, paving the way for innovative applications in environmental remediation and resource recovery.