Behavior of CaTiO3/Nano-CaO as a CO2 Reactive Adsorbent

Abstract

This study focuses on the preparation of a CaTiO 3 -coated nano-CaO-based CO 2 adsorbent (CaTiO 3 /nano-CaO) for the improvement of sorption properties. The CaTiO 3 -coated nano-CaO adsorbent was prepared by forming Ti(OH) 4 from the hydrolysis of titanium alkoxide in a nano-CaCO 3 suspended solution. The resulting Ti(OH) 4 -coated nano-CaCO 3 was then heated and calcined. Test results from transmission electron microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy show that an obvious film of TiO 2 was formed on the surface of nano-CaCO 3 after heating. X-ray diffraction analysis also showed that the nano-CaTiO 3 layer was formed at 750 °C, a calcination temperature that causes the reaction of TiO 2 with nano-CaO. The cyclic tests of reactive sorption capacity were conducted in a thermogravimetric analyzer under the following conditions: 0.02 MPa CO 2 partial pressure, carbonation temperature of 600 °C, and calcination temperature of 750 °C. Test results showed that CaTiO 3 coated onto the nano-CaO caused a significant improvement in the durability of the capacity for reactive sorption. Nano-CaO that had an optimum content of 10 wt % TiO 2 showed significantly stable CO 2 reactive sorption capacity (5.3 mol/kg) after 40 cyclic carbonation−calcination runs compared to the reactive sorption capacity of CaO without TiO 2 coating (3.7 mol/kg).