Synthesis and characterization of zeolite sourced from rice husk lignocellulosic waste ash

Abstract

Rice husk, typically deemed a byproduct in the rice industry, presents a promising avenue for the production of valuable materials including zeolites, which are highly sought-after as crucial adsorbent support materials. This study intricately focuses on the synthesis of zeolites utilizing rice husk ash (RHA) as the SiO₂ source with a Fourier-Transform Infrared (FTIR) analysis guided optimized addition of aluminum from external sources. The produced zeolite, as evidenced by the FTIR spectrum, showcases distinct functional groups associated with zeolite formation, notably the -O-H band at 2851 cm−1 and the bending vibration of adsorbed water molecules at 1659 cm⁻¹. Prominent Si-O-Si, Al-O, and Si-O-Al functional groups absorbed further validate zeolite framework formation. Employing a straightforward method involving alkaline extraction and acid precipitation, the study successfully yields pure silica xerogel from this waste, minimizing mineral contaminants. The resulting xerogel demonstrates 91% silica content and 2.6-4% moisture. Subsequent water washing proves effective in further reducing mineral content (Na < 200ppm, K < 400ppm). X-ray Diffraction (XRD) analysis of the zeolites reveals the amorphous nature of silica xerogels, emphasizing their heightened activity for zeolite Y and P production. This comprehensive investigation not only underscores the potential for converting rice husk waste into valuable materials but also contributes to sustainable and efficient utilization practices.