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.