Study on the synthesis of ordered mesoporous alumina with high specific surface area using inorganic aluminum sources and its adsorption performance for carbon dioxide

In this work, inexpensive aluminum nitrate was used as the raw material and ammonium carbonate as the precipitant. Ordered mesoporous alumina (OMA) with a high surface area was synthesized using suitable template agents and auxiliary agents. The synthesized materials underwent characterization via X-ray powder diffraction (XRD), N₂ adsorption-desorption (BET), transmission electron microscopy (TEM), and other analytical techniques. The effects of various template agents, aging durations, calcination methods, and calcination temperatures on the structure of the synthesized OMA were investigated. Key factors influencing the formation of inorganic precursors, the self-assembly of template agents with inorganic precursors, and the pore formation process (involving template agent and water removal) during synthesis were analyzed. Using the synthesized OMA as the substrate and triethylenetetramine (TETA) as the modifier, the impact of modified materials on CO₂ adsorption performance was assessed. The results showed that OMA prepared with P123 as the template agent and ammonium dihydrogen phosphate as the auxiliary agent exhibited a specific surface area of 545.2 m²/g, an average pore diameter of 3.8 nm, and a pore volume of 1.01 cm³/g. The addition of auxiliary agents significantly increased the specific surface area of the synthesized material. The modified TETA-OMA, with a loading capacity of 50 %, achieved an adsorption capacity of 216.25 mg/g at an intake flow rate of 20 mL/min and an adsorption temperature of 40 °C. After six cycles of adsorption-desorption recycling, minimal changes were observed in the adsorption performance, indicating excellent regeneration capability. The synthesized high-surface-area ordered mesoporous alumina holds potential for industrial applications.