Wastes against wastes treatment: Industrial silica fume derived porous solid amine adsorbent for efficient and reversible ultralow-pressure CO2 adsorption

•MPS-TEPA-30 affords an 1.5 mmol g−1 CO2 adsorption capacity at 10 mbar of ultralow pressure.•MPS-TEPA-30 demonstrates remarkable CO2 adsorption enhancement compared to SBA15-TEPA-30 and MCM41-TEPA-30.•MPS-TEPA-30 affords low preparation cost and exceptional stability in seven adsorption–desorption cycles.•The good thermal stability of adsorbent makes it suitable for high-temperature adsorption–desorption processes.•MPS-TEPA-30 demonstrates excellent adsorption selectivity for CO2/N2 (1:1) mixture at 323 K and 10 mbar. The utilization of ambient low-pressure CO2 adsorption for carbon neutrality initiatives holds great potential. However, conventional liquid amine absorption methods for CO2 capture are plagued by high energy consumption and equipment corrosion issues. In this study, we present a novel approach using industrial waste silica fume (SF) as a precursor and tetraethylenepentamine (TEPA) as a chemical modifying agent to efficiently synthesize low-cost mesoporous solid amine adsorbents within the waste-derived mesoporous powder sorbents (MPS) series. Employing the static adsorption technique, the impact of both adsorption temperature and amine loading on the CO2 adsorption efficacy was comprehensively investigated. The optimized sample, MPS-TEPA-30, demonstrated a superior CO2 adsorption capacity, achieving 2.22 mmol g−1 at 323 K and 1 bar, a significant 6.8-fold increase compared to the unmodified MPS material (0.326 mmol g−1). Additionally, MPS-TEPA-30 demonstrated notable performance advantages, surpassing SBA15-TEPA-30 and MCM41-TEPA-30 with near 1.49- and 2.12-fold increases in adsorption capacity, respectively. Impressively, MPS-TEPA-30 exhibited remarkable adsorption ability beyond 1.5 mmol g−1 at ultralow pressures (