Characteristics of New Potassium-Based Sorbents Prepared with Nano-Titanium Oxide for Carbon Dioxide Capture

The CO 2 absorption and regeneration properties of novel regenerable potassium-based dry TiO 2 sorbents were measured in a fixed bed reactor at low temperature conditions (CO 2 absorption at 60 °C and regeneration at 200 °C). The K 2 CO 3 -based sorbent developed in this study showed excellent characteristics in regard to CO 2 absorption and regeneration. It satisfied the requirements of a sorbent: significant CO 2 capture capacity (85 mg CO 2 /g sorbent to 92 mg CO 2 /g sorbent) and fast and complete regeneration at a low temperature condition (1 atm, 150 °C). In particular, a K 2 CO 3 -based sorbent prepared (KTi(S-B)I30) by the impregnation of nano-size TiO 2 with K 2 CO 3 showed excellent characteristics in CO 2 absorption without pre-treatment with water vapor. This result was because of the effect of the textural property of the TiO 2 used as a support, which had a uniform pore size distribution in a very narrow range with a maximum of about 100 A, unlike the K 2 CO 3 -based AC sorbent, which showed a very wide distribution ranging from 1 A to 1000 A. In addition, it had a relatively large surface area of about 45.4 m 2 /g. As a result, the CO 2 capture capacity of the sorbent was found to be affected by the pore size of the sorbent, as well as the surface area of the sorbent.