Characterization of calcium oxide prepared by hydration-dehydration method

Abstract

Calcium oxide, CaO is an important inorganic catalyst, used in toxic waste remediation agent and adsorbent. In this study, CaO was prepared by hydrationdehydration method using commercial calcium oxide as starting material, converted into its hydroxide by sonicating it in ultrasonic water bath for one hour, then, undergone dehydration step by heating under high vacuum at different temperatures which were 200, 300, 400, 500, 600, 700 and 800oC respectively. The prepared samples were characterized using several techniques including Thermal Gravimetry Analysis (TGA), Fourier Transform Infrared (FT-IR), X-Ray Diffraction (XRD), Nitrogen Gas Adsorption (NA) and Field Emission Scanning Electron Microscope (FESEM). The FT-IR shows that the elimination of hydroxide and carbonate species increased with the increasing calcination temperature. By XRD, the prepared CaO- 700 shows the smallest particle size which is 27.93 nm compared to commercial CaO with particle size of 37.14 nm. The basicity study of the prepared CaO carried out using back titration method showed that the prepared CaO-800 was found to be very high basic which is 1.78 mmol/g. The result obtained using Electron Spin Resonance spectroscopy to the CaO-800 irradiation by UV in H2, showed that the cavity of CaO-800 was too large to trap electrons, containing several impurities such as manganese, Mn2+ that might inhibit the formation of trapped electron in CaO.