The Utility of Rice Husk Ash from Biomass Power Plant: Synthesis of Na-A and Na-X Zeolites Using the Two Step Method Hydrothermal

Abstract

Rice husk ash (RHA), a solid waste from biomass power plant was used as a raw material to synthesize Na-A and Na-X zeolites. In fact, high silica content of this material opens a possibility for it to be used as a potential zeolite precursor. In this study, a medium size particle of RHA has been reused to prepare zeolite with high purity. After segregation by mechanical sieving, the medium size particle fraction of RHA was subjected to alkali fusion treatment followed by dissolution and then residue separation to produce clear silicate supernatant as the silica source for preparing the low-silica zeolites. High purity Na-A and Na-X zeolites were prepared using hydrothermal treatment by optimizing the process condition, curing time, hydrothermal temperature and Si/Al molar ratio in the reaction mixture. The utilization of zeolite for adsorption of cadmium using batch technique was investigated. The effect of time, dosage and initial concentration of solutions on the adsorption was investigated. The result showed that adsorption capacity of Na-A zeolite was much higher than that of Na-X zeolite. The equilibrium data were fitted by the Langmuir model. Na-A and Na-X zeolites synthesized with the optimal condition possessed a maximum value of cation exchange capacity (CEC) of 470 meq/100 g and 503 meq/100g, respectively.