Optimized valorization of green SiO2-rich sugarcane bagasse white ash for effective pollutant adsorptive removal in sustainable wastewater remediation

• High-purity silica (93.27%) was efficiently converted from sugarcane bagasse ash using optimized acid pretreatment and pyrolysis. • Achieved 90.91% methylene blue dye removal efficiency under optimized conditions. • Adsorption kinetics followed a pseudo-second-order model, indicating chemisorption as the dominant mechanism. • Demonstrates dual benefits of waste utilization and wastewater remediation. Sugarcane bagasse ash exhibits exceptional potential as a green material for silica (SiO₂) production and dye removal, contributing significantly to environmental pollution remediation. In this study, sugarcane bagasse was pretreated with hydrochloric acid (HCl) and pyrolyzed at varying temperatures and durations to produce sugarcane bagasse white ash with optimal silica yield. Characterization using TGA, SEM, EDS, FTIR, and XRD confirmed the presence of silica with the highest content of 93.27%, which was subsequently employed as an adsorbent for aquatic pollutant removal. The adsorption performance toward methylene blue (MB) dye was evaluated under different contact times, adsorbent dosages, and pH values, achieving a maximum removal efficiency of 90.91%. Kinetic analysis indicated that the adsorption process followed a pseudo-second-order model, with chemisorption as the predominant mechanism. These findings reveal that silica derived from sugarcane bagasse ash is an economically affordable and highly efficient adsorbent for sustainable wastewater treatment.