This work presents a simple method for the preparation of the Mg-doped nanocomposite copper silicates (Mgx-Cu1−x-SiO3) (x=0.25, 0.5, 0.75 and 0.9) using coal gangue waste as the silicon source for CO2 capture at low temperature. The as-prepared Mgx-Cu1−x-SiO3 was systemically characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller surface area analysis (BET). The results suggest that all Mgx-Cu1−x-SiO3 possess large surface areas, micropores and mesoporous structures composed of the agglomerates of small nanoparticles. They exhibit high CO2 adsorption capacity at 298.15 K under 1 bar, and that of Mg0.9-Cu0.1-SiO3 was the highest with the value of 16.73 cm3/g. The Freundlich isotherm model fits the CO2 adsorption isotherm well. Thermodynamic analysis indicates that the CO2 adsorption on Mg0.9-Cu0.1-SiO3 is exothermic (ΔH°<0), chaotic (ΔS°<0), and spontaneous (ΔG°<0). This work highlights the low-temperature adsorption behavior of silicate materials on CO2, which can provide some research basis for the utilization of silica in coal gangue.

中文翻译：

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以煤矸石为原料制备纳米掺镁硅酸铜材料及其对CO2的吸附表征

这项工作提出了一种使用煤矸石废物作为硅源以低浓度捕获 CO2 的硅源制备掺镁纳米复合硅酸铜 (Mgx-Cu1-x-SiO3) (x=0.25、0.5、0.75 和 0.9) 的简单方法。温度。通过扫描电子显微镜 (SEM)、傅里叶变换红外光谱 (FTIR)、X 射线粉末衍射 (XRD)、X 射线光电子能谱 (XPS) 和布鲁瑙尔对制备的 Mgx-Cu1-x-SiO3 进行了系统表征。 -Emmett-Teller 表面积分析 (BET)。结果表明，所有 Mgx-Cu1-x-SiO3 都具有大的表面积、微孔和由小纳米颗粒团聚体组成的介孔结构。它们在 298.15 K 和 1 bar 下表现出较高的 CO2 吸附能力，其中 Mg0.9-Cu0.1-SiO3 的吸附能力最高，为 16.73 cm3/g。Freundlich 等温线模型很好地拟合了 CO2 吸附等温线。热力学分析表明，Mg0.9-Cu0.1-SiO3 上的 CO2 吸附是放热的（ΔH°<0）、混沌的（ΔS°<0）和自发的（ΔG°<0）。该工作突出了硅酸盐材料对CO2的低温吸附行为，可为硅石在煤矸石中的利用提供一定的研究依据。