Structural and microstructural analysis of different CaO–NiO composites and their application as CO2 or CO–O2 captors

Abstract

In this work, CaO–NiO mixed oxide powders were prepared by mechanical mixing and incipient impregnation methods. The samples were characterized structurally and microstructurally, where it was determined that microstructural properties changed depending on the NiO addition method. The CO2 and CO–O2 capture evaluations were performed in a thermogravimetric analyzer. These results showed that the presence of nickel significantly modified the CO2 and CO capture processes. In both cases, the CO2 or CO capture temperature was shifted to lower values in the CaO–NiO composites in comparison to the CaO sample. Nevertheless, the carbon oxide captures seemed to decrease as a function of the nickel addition. It was associated to the nickel superficial deposition over the CaO particles. On the other hand, the CO–O2 oxidation was importantly enhanced and maintained, for long times, with the presence of nickel independently of the calcium oxide carbonation process.