SYNTHESIS OF ZEOLITE FROM BAMBOO LEAF ASH AND ALUMINUM CANS WASTE WITHOUT ADDITION OF COMMERCIAL PRECURSORS

• Main Author: Yusrina Kulsum, Anita
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/87210
• Institution: Institut Teknologi Bandung

Bamboo leaf ash is an abundant biomass waste in Indonesia and can be utilized for zeolite production. In this study, H-SOD zeolite was synthesized using bamboo leaf ash without pre-treatment as the silica source and waste aluminum cans as the aluminum source. The synthesis was performed using the sol-gel and hydrothermal methods at a temperature of 90°C. The molar ratio of SiO?/Al?O? and Na?O/Al?O? determines the formation of a single-phase zeolite type. The molar ratios of SiO?/Al?O? and Na?O/Al?O? were calculated based on the silica content in the bamboo leaf ash. Additionally, the synthesis time was optimized to obtain pure zeolite crystals. This study aims to determine the effects of the molar ratios of SiO?/Al?O? and Na?O/Al?O? and synthesis time on the type of zeolite formed. The effect of the molar ratio of SiO?/Al?O? was investigated under constant reaction conditions, namely a synthesis time of 4 hours and a Na?O/Al?O? ratio of 17. The synthesis results with a SiO?/Al?O? ratio of 5 showed the formation of H-SOD zeolite along with a minor phase of metastable RHO zeolite. A SiO?/Al?O? ratio of 7 produced single-phase H-SOD zeolite. Increasing the SiO?/Al?O? ratio to 9 did not produce zeolite due to the lack of Na? and OH? ions, which play a role in the formation of zeolite crystals. To study the effect of the molar ratio of Na?O/Al?O?, zeolite synthesis was conducted with a SiO?/Al?O? ratio of 7 and varying Na?O/Al?O? ratios of 17, 21, and 25, with synthesis times of 4, 12, and 20 hours. The synthesis results showed the formation of single-phase H-SOD zeolite at a Na?O/Al?O? ratio of 17 for all reaction times (4, 12, and 20 hours). Samples with a Na?O/Al?O? ratio of 21 and a 4-hour synthesis time produced H-SOD zeolite and RHO zeolite as a minor phase. The RHO phase decreased in the samples synthesized for 12 hours, while the samples synthesized for 20 hours showed damage to the zeolite framework. Synthesis with a Na?O/Al?O? ratio of 25 and synthesis times of 4, 12, and 20 hours resulted in H-SOD zeolite as the main phase and RHO zeolite as a minor phase. Based on the results, the optimum conditions for producing single-phase H SOD zeolite are a SiO?/Al?O? ratio of 7, Na?O/Al?O? ratio of 17, and a synthesis time of 4 hours. Further characterization using SEM-EDX for the single-phase H-SOD zeolite showed a coral-like morphology and a low Si/Al ratio of 1.28. Zeolite H-SOD synthesis from bamboo leaf ash and Al(OH)? was performed to replace the process of making NaAlO? from waste aluminum cans, which takes a long time, allowing the synthesis process to be applied in high school-level educational modules. The synthesis was conducted under the same optimum reaction conditions. The results showed that the H-SOD zeolite produced had similar characteristics to those synthesized using waste aluminum cans, but with a higher Si/Al ratio of 1.32. Therefore, this H-SOD zeolite synthesis module can be applied as part of material chemistry learning at the high school level, with an emphasis on stoichiometry concepts to calculate the molar ratios of precursors in zeolite synthesis.