Light olefins by methane partial oxidation using hydrated waste eggshell as catalyst

Abstract Catalysts obtained from the residual eggshell were prepared by calcination-hydration-calcination cycles under static atmosphere or under air flow and evaluated in the oxidative coupling of methane to obtain C2-C3 hydrocarbons. It was found that the calcination-hydration-calcination cycles under different conditions influence the specific surface area, the crystallinity and the basicity of the obtained materials. The production of light olefins from methane was observed under all samples. The best results were obtained for the hydrated sample calcined under air flow, reaching a methane conversion of 30% and selectivity for ethylene above 53% at 800 °C. The hydrated and muffle-calcined sample showed a higher C2/CO2 ratio. These differences are attributed to the strength of the basic sites and the presence of surface lattice oxygen.