Abstract
Methylene blue (MB) is a hazardous pollutant with severe impacts on human health and marine ecosystems. To solve these issues, this work investigates the removal of MB from wastewater using sodium alginate beads embedded with natural zeolite clinoptilolite (NZC) modified with HCl and NaOH. To comprehend the changes in NZC physicochemical properties, it was modified with different concentrations of HCl and NaOH (0.5, 1.0, 3.0, and 5.0 M) and extensively characterized using Fourier-transform infrared spectroscopy (FTIR-ATR), and nitrogen adsorption analysis. Both HCl-NZC and NaOH-NZC beads achieved 100% MB removal efficiency, with maximum adsorption capacities of 45.80 mg/g and 45.09 mg/g, respectively. The adsorption process followed the Langmuir isotherm model with high correlation value (R²) of 0.9952 (HCl-NZC) and 0.9907 (NaOH-NZC), indicating monolayer adsorption on a homogeneous surface. This study serves as a preliminary investigation into the adsorption behavior of acid- and base-modified NZC encapsulated in alginate beads for MB removal. The findings demonstrate that the modified beads exhibit strong adsorption capacity and stability, suggesting their potential application as fillers or active components in future zeolite-based composite membrane systems for efficient dye removal.