Synthesis of Zeolite from ash of biomass power plant by using hydrothermal process and application of synthetic Zeolite

Abstract

Unlike biomass, combusted biomass in the form of fly ash from biomass power plant may pose a major problem in waste management. Nonetheless, they have high potential for applications, especially in construction material industry. Zeolite production is one of the potential applications for obtaining high value products from these fly ashes. This study focused on synthesis of zeolite using hydrothermal process under atmospheric pressure. A matrix of experiments was designed for three different sources of fly ash; namely, pure rice husk, biomass from power plant No. 3, and biomass from power plant No. 4. Zeolite synthesis was carried out under varied experimental conditions that include type of basic solution, concentration of alkali, temperature, and reaction time. Phase analysis via X-ray diffraction spectrometry (XRD) identified zeolite P as a major phase in the synthetic zeolite samples from the three recipes. The optimum condition for the pure rice husk ash treatment was with 3 M NaOH, 99±1ºC, and 24 hours of reaction time. Those for Biomass 3 and Biomass 4 were obtained at 2 M NaOH, 99±1ºC, and 24 hours. Zeolites synthesized at the optimum conditions for each recipe of fly ash had cation exchange capacities of 381.08, 264.34, and 261.96 mgCaCO3/g zeolite, respectively. The synthetic zeolites produced from the abovementioned optimum conditions were then tested for heavy metal treatment application. Maximum removal efficiency for lead (Pb) of the three biomass recipes were 82.43%, 74.68%, and 61.70%, respectively, at initial lead concentration of 1000 mg/L and pH 5.