Synthesis of Zeolite from Coal Fly Ash: Its Application as Water Sorbent

Abstract

Coal fly ash (CFA) was used as raw material for zeolite synthesis by fusion method. In detail, it was mixed with NaOH (with ratio of 2.25) and treated under various temperatures. Synthesized zeolite was characterized using various techniques i.e. X-rayfluorescence (XRF), X-ray diffraction (XRD), and BET surface area analysis. It was found that the surface area of synthesized zeolite were in the range of 49.407-69.136 m²/g depending on the preparing condition, compared to the surface area of CFA about 17.163 m²/g. In addition, according to the XRD result, it was proven that the form of zeolite was Sodium Aluminum Silicate Hydrate (1.08Na₂O.Al₂O₃.1.68SiO₂.1.8H₂O). The synthesized zeolite was then applied as water sorbent to remove water from ethanol solution (95%). The testing results revealed that the optimal fusion temperature was 450^oC, which provided maximum percentage of water removal from ethanol solution (from 95% ethanol to 99.25% ethanol). For comparison, commercial-grade molecular sieve was also tested and was found to increase ethanol concentration from 95% to 99.61%. Hence, it is concluded that our synthesized zeolite provides comparable performance to the commercial-grade molecular sieve.