<p>Zeolites are currently of significant importance as nanomaterials in selective adsorption, ion exchange, and heterogeneous catalysis. However, the limited availability and rising cost of conventional precursors, combined with zeolites increasing global demand, underscore the need to explore low-cost, abundant alternative raw materials. This study focuses on the zeolitization of natural silica and coal fly ash by-product through an innovative approach using the L9 Taguchi orthogonal array to optimize key synthesis parameters, namely NaOH concentration, synthesis duration, hydrothermal temperature, and the SiO₂/Al₂O₃ mass ratio. The resulting powders were characterized using various analytical techniques, including XRD, FTIR, SEM/EDX, and DTA/TG. The zeolitization rate of the starting materials was considered the response parameter, and the influence of operational factors was assessed using ANOM /ANOVA analyses. Under optimal conditions (160 °C, 36 h, 1.5 M NaOH, and SiO₂/Al₂O₃ mass ratio of 2.2), a zeolitization efficiency of 89% was achieved, with analcime identified as the dominant crystalline phase. Subsequently, the adsorption performance of the optimal sample was evaluated using methylene blue (MB) as a model contaminant. Kinetic studies indicated that the adsorption followed a pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Equilibrium data fit well with the Langmuir, Freundlich, and Temkin isotherm models, indicating that the adsorption involves both monolayer coverage and heterogeneous surface interactions. Under optimal conditions (MB 40 mg L⁻¹, pH 12, contact time 80 min, adsorbent dosage 2 g L⁻¹), a high removal efficiency of 99.69% was achieved, confirming the effectiveness and cost-efficiency of the synthesized analcime zeolite.</p> Graphical Abstract <p></p>