Energy-Saving Effect of Low-Cost and Environmentally Friendly Sepiolite as an Efficient Catalyst Carrier for CO2 Capture

Recently, the development of efficient solid acid catalysts to promote the CO2 desorption rate while reducing energy consumption has attracted much attention. In this work, low-cost environmentally friendly sepiolite (SEP) clay was evaluated as a support of metal oxide (Fe2O3, CuO) catalysts. By comparing their catalytic performances for CO2 desorption from CO2-rich monoethanolamine (MEA) solution at 100 °C, the obtained results showed that the tested catalysts can accelerate the CO2 release rate and reduce heat consumption in comparison with the non-catalytic MEA solution. The relative heat duty found decreased in the following order: blank (100%) > SEP (66.4%) > CuO-SEP (58.8%) > Fe2O3-SEP (54.0%). Recycling tests to study stability demonstrated that Fe2O3-SEP can maintain its catalytic efficiency after six recycling runs. Characterization studies revealed that a high mesoporous specific surface area and a high ratio of Brønsted and Lewis acid sites are beneficial to enhancing the activity of the catalysts. In addition, a possible catalytic mechanism for CO2 desorption was proposed. As a result, this work proved that SEP has the potential to be a low-cost and competitive catalyst carrier for CO2 capture.