Reactive silica enrichment from sugarcane bagasse ash by optimized calcination and alkali activation for zeolite applications

Abstract

Sugarcane bagasse ash (SCBA), an abundant agro‐industrial waste, was investigated as a sustainable silica–alumina‐rich precursor material for potential Zeolite A synthesis. This study examines the influence of calcination temperature and alkali activation on the structural, compositional, and morphological characteristics of SCBA. Controlled calcination at 500–800°C was performed to remove residual carbonaceous matter and enhance structural reactivity, followed by alkali treatment with 1–3 M NaOH at 100°C. Calcination at 600°C for 2 h produced favorable structural activation with reduced impurity phases and improved silica–alumina characteristics, while treatment at 800°C resulted in severe sintering and loss of reactive powder morphology. A moderate alkali concentration (approximately 2 M NaOH) promoted silica‐rich phase enhancement and impurity reduction, whereas higher alkali concentrations led to excessive sodium incorporation and possible silica dissolution. XRD and FTIR analyses confirmed the development of reactive amorphous aluminosilicate phases with stronger SiOSi vibrational characteristics after thermochemical treatment. SEM and TEM analyses revealed the transformation of irregular carbonaceous particles into porous, structurally activated morphologies, while BET analysis of raw SCBA showed a surface area of 134.306 m ² /g, with mesoporous characteristics. The study demonstrates an effective thermochemical activation route for converting SCBA into a reactive silica–alumina‐rich material suitable for potential Zeolite A precursor applications. This approach supports sustainable waste valorization, resource recovery, and circular economy‐based development of low‐cost materials for future environmental remediation applications.