Shuai Liu,Dicka Ar Rahim,Yan Zhang,Dan Wang,Ekkachai Kanchanatip,Yi He,Mi Yan
To advance the utilization of high-concentration CO2 produced in biogas upgrading, it is essential to remove associated hydrogen sulfide (H2S). This study presents a series of bimetallic Fe–Cu oxides supported on multi-walled carbon nanotubes (MWCNTs), which were synthesized to efficiently remove H2S from CO2-rich gas at low temperatures. The synergy of the bimetallic elements not only forms a multifaceted active phase but also causes new defects on the MWCNTs, creating more H2S/CO2 separation sites. The adsorption experiments demonstrate that the deep H2S removal performance of the adsorbent is unaffected by the CO2 concentration, achieving a maximum adsorption capacity of 30.11 mg g−1, which exceeds that of commercial desulfurizers and previously reported adsorbents. Additionally, density functional theory calculations were employed to elucidate that the introduction of Cu species increases the gap in the average adsorption energies between H2S and CO2. The adsorbent also exhibited stability after 4-cycle regeneration at room temperature, maintaining 62.6% of its initial H2S capacity. This work underscores the potential of Fe–Cu oxide/MWCNTs adsorbents as a viable, regenerable solution for H2S removal in CO2 purification, offering implications for carbon-negative construction.
CaO-based adsorbents present a promising approach for industrial CO 2 emissions reduction. This study systematically investigates the influence of adsorption temperature, adsorbent mass, CO 2 concentration, and flow rate on CO 2 capture efficiency using commercial CaO via thermogravimetric analysis (TGA). Optimal adsorption performance, achieving a capacity of 0.62 g/g and a rate exceeding 0.14 g/g/min, was observed at 750°C, 7 mg mass, 20% CO 2 , and 20 mL/min flow. Characterization (SEM, BET, and FTIR) indicated that 750°C preserved a hierarchical pore structure (24.64 m 2 /g surface area, 0.1026 cm 3 /g pore volume, and 7.08 nm average pore size), mitigating sintering and pore blockage while confining carbonation to surface layers. Kinetic modeling confirmed chemisorption dominance (pseudo-second-order). These findings elucidate fundamental mass/heat transfer limitations, supporting the development of enhanced CaO-based carbon capture, utilization, and storage (CCUS) technologies. Applied sciences; Chemistry; Environmental science.
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