Abstract

Montmorillonite, a natural and abundant clay, was subjected to acid treatments in HCl solutions for different times to enhance its physicochemical properties for CO₂ adsorption. Acid activated montmorillonites were characterized by elemental analysis, XRD, FTIR, nitrogen physisorption, TGA, and NMR to evaluate the physicochemical changes due to the acid treatment. Besides, these samples were examined as CO₂ adsorbents, evaluating the influence of the modified textural characteristics on the affinity of montmorillonite towards CO₂ capture. After 3 h of acid treatment, the specific surface area of clay increased from 39 to 202 m²/g, while the pore volume increased from 0.05 to 0.31 cm³/g. CO₂ adsorption isotherms were carried out at 0, 15, and 30 °C, showing that acid activated clays were much more efficient for CO₂ adsorption than raw materials. Further studies on the CO₂ adsorption process were performed: experimental equilibrium data were correlated by using Langmuir, Freundlich, and Sips models, and the isosteric heat of adsorption was calculated from the Clausius–Clapeyron equation.

Graphic Abstract

中文翻译：

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酸活化对蒙脱石CO 2吸附能力的影响

摘要

蒙脱土（一种天然且丰富的粘土）在HCl溶液中进行了不同时间的酸处理，以增强其吸附CO _2的理化性能。通过元素分析，XRD，FTIR，氮物理吸附，TGA和NMR对酸活化的蒙脱石进行表征，以评估由于酸处理而产生的理化变化。此外，将这些样品作为CO ₂吸附剂进行了检查，评估了改性的织构特性对蒙脱石对CO ₂捕获的亲和力的影响。酸处理3小时后，粘土的比表面积从39增加到202 m ² / g，而孔体积从0.05增加到0.31 cm ³ / g。一氧化碳₂吸附等温线分别在0、15和30°C进行，表明酸活化粘土对CO _2的吸附比原材料有效。进行了有关CO ₂吸附过程的进一步研究：使用Langmuir，Freundlich和Sips模型对实验平衡数据进行关联，并根据Clausius-Clapeyron方程计算吸附的等渗热。

图形摘要