Aluminum-modified diatomite efficiently catalyzes the CO2 desorption to achieve low-energy consumption regeneration of amine solution

Currently, the addition of solid acid catalysts is considered a promising strategy for promoting CO₂ desorption and reducing regeneration energy consumption. In this work, the abundant and environmentally friendly diatomite was selected as the carrier to prepare a series of composite catalysts (denoted as Al-D) with different Al 2 O 3 loadings through precipitation method. The catalytic desorption performance (desorption amount, desorption rate, relative heat duty) of the composite catalysts was studied in 100 mL of 5 M monoethanolamine (MEA) solution at 87 °C. It was found that the composite catalysts can effectively promote CO 2 desorption, with 30 % Al-D showing the best catalytic performance. Specifically, the 30 % Al-D increased the CO 2 desorption amount by 35.49 %, increased the maximum desorption rate by 59.09 %, and reduced the relative heat duty by 43.23 % versus the blank group. The physicochemical properties of the catalysts were investigated by a variety of characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and ammonia temperature-programmed desorption (NH₃-TPD). Based on these findings, a potential reaction mechanism was proposed. Finally, the 50 cycles of experiments showed that 30 % Al-D had excellent stability and feasibility for large-scale application. This work not only offers a novel strategy for developing high-performance catalysts from naturally abundant mineral materials, but also provides a material foundation and theoretical insight for energy conservation and cost reduction in industrial carbon capture processes. • Diatomite was used to prepare the cost-effective amine-based CO 2 capture catalyst. • The catalyst boosted CO₂ desorption by 35.49 % and lowered heat duty by 43.23 %. • The catalyst showed excellent stability performance in 50 cyclic experiments. • This work showed natural mineral materials' great potential for CO₂ capture.