DETERMINATION OF OPTIMUM CONDITION ON SYNTHESIS OF ZEOLITE

FROM COAL FLY ASH USING AN EXPERIMENTAL DESIGN

抄録

Since the main components of fly ash are SiO₂ and Al₂O₃, which exhibit a similar chemical structure of zeolite, this studied was concentrated on the used of fly ash as raw materials for synthesizing zeolite. The objective of this study was to define an optimum condition on fly ash synthesis, which would conciliate a high cation exchange capacity (CEC) of synthesized zeolite. To achieve this goal, the strategy relied on the use of experimental design methodology. The effects of five parameters including sieve size, activated temperature, NaOH concentration, reaction temperature, and reaction time were determined by using the two factorial design approach to specify the significant parameters on the formation of zeolite from fly ash. In the first step, the reaction temperature was found to be the most important parameter and two other significant parameters are activated temperature and reaction time. The second step of this studied, the three significant parameters were controlled at the various values and the cation exchange capacity (CEC) were determined for an optimum condition. Reaction temperature, activated temperature, and reaction time were in the range of 40 to 150°C, 800 to 1100°C and 12 to 96 hours, respectively. The results showed that the optimum condition, which exhibited the highest CEC (636 cmol/kg) of synthesized zeolite was at reaction temperature of 110°C, activated temperature of 800°C, and reaction time of 96 hours. Therefore, the development of a technique for the utilization of coal fly ash is essential to preserve the environment and to recycle the waste materials. Zeolite-like material can be use as an alternative adsorbent for the removal of heavy metals such as Cd, Zn, Pb from wastewater.