A Novel Mesoporous SiO2 Material with MCM-41 Structure from Coal Gangue: Preparation, Ethylenediamine Modification, and Adsorption Properties for CO2 Capture

Abstract

A novel mesoporous SiO2 material (M-SiO2) with MCM-41 structure was readily fabricated from the inexpensive coal gangue via a hydrothermal reaction in the presence of cetyltrimethylammonium bromide (CTAB) for CO2 capture. On the basis of orthogonal experimental results, the optimum conditions for the preparation of M-SiO2 were identified as follows: the SiO32– leaching of 21 g/L from coal gangue, the CTAB concentration of 0.25 mol/L, the HCl concentration of 2.5 mol/L, the hydrothermal temperature of 393.15 K, and the hydrothermal time of 20 h. Under the optimum condition, the M-SiO2 exhibited an adsorption capability of 9.61 mg/g to 8% CO2 at 298.15 K. To further improve the CO2 adsorption performance, the M-SiO2 was chemically modified using ethylenediamine (EDA), and the optimum conditions for the modification of M-SiO2 were identified as follows: the impregnation time of 10 h, the drying temperature of 343.15 K, and the ratio of EDA/M-SiO2 = 2:1. Under the optimum conditions, the adsorption capability...