Simple marble dust for integrated carbon capture and utilization with simulated flue gas containing oxygen and water

Marble dust is a low-cost, robust, and environmentally friendly natural material for integrated carbon capture and utilization (ICCU). This study demonstrates the effect of oxygen and water in the flue gas on the ICCU performance of marble dust when it is integrated with reverse water gas shift reaction (RWGS), which could potentially be scaled up for the application of marble dust. The inclusion of water vapor in flue gas augmented the capture ability of calcined marble (CM) to eliminate 12.8 mmol g⁻¹ CO₂ from flue gas and achieved the highest CO yield of 10.2 mmol g⁻¹ with almost 100 % CO selectivity. The introduction of O₂, despite lowering CO₂ capture efficiency, retained the pore structure of CM, boosting a lasting CO producing. With inert MgO as a stabilizer in CM, the segregation between two-layered CaO and MgO crystalline structure alleviated the sintering and carbon deposition, enhanced diffusion and retained superior structural stability over consecutive cycles than raw CaO.