CO₂ adsorption is a promising strategy to reduce costs and energy use for CO₂ separation. In this study, we developed CO₂ adsorbents based on lightweight and flexible cellulose nanofiber aerogels with monolithic structures prepared via freeze-casting, and cellulose acetate or acetylated cellulose nanocrystals (a-CNCs) were introduced into the aerogels as functional materials using an impregnation method to provide CO₂ affinity. The microstructure of the adsorbent was examined using scanning electron microscopy, and compression tests were performed to analyze the mechanical properties of the adsorbents. The CO₂ adsorption behavior was studied by recording the adsorption isotherms and performing column breakthrough experiments. The samples showed excellent mechanical performance and had a CO₂ adsorption capacity of up to 1.14 mmol/g at 101 kPa and 273 K. Compared to the adsorbent which contains cellulose acetate, the one impregnated with a-CNCs had better CO₂ adsorption capacity and axial mechanical properties owing to the building of a nanoscale scaffold on the surface of the adsorbent. Although the CO₂ adsorption capacity could be improved further, this paper reports a potential CO₂ adsorbent that uses all cellulose-based materials, which is beneficial for the environment from both resource and function perspectives. Moreover, the interesting impregnation process provides a new method to attach functional materials to aerogels, which have potential for use in many other applications.

中文翻译：

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轻巧，灵活，多功能的各向异性纳米纤维素基气凝胶，可吸附CO 2

CO ₂吸附是降低CO ₂分离成本和能耗的一种有前途的策略。在这项研究中，我们开发了基于轻质和柔性的纤维素纳米纤维气凝胶的CO ₂吸附剂，该气凝胶具有通过冷冻铸造制备的整体结构，并且使用浸渍法将醋酸纤维素或乙酰化纤维素纳米晶体（a-CNC）作为功能材料引入到气凝胶中提供CO ₂亲和力 使用扫描电子显微镜检查吸附剂的微观结构，并进行压缩测试以分析吸附剂的机械性能。一氧化碳₂通过记录吸附等温线并进行柱穿透实验研究吸附行为。样品表现出优异的机械性能，在101 kPa和273 K下的CO ₂吸附容量高达1.14 mmol / g。与含乙酸纤维素的吸附剂相比，浸渍有a-CNC的吸附剂具有更好的CO ₂吸附能力和由于在吸附剂表面上建立了纳米级支架，因此具有轴向机械性能。尽管可以进一步提高CO _2的吸附能力，但本文报道了潜在的CO ₂使用所有基于纤维素的材料的吸附剂，从资源和功能的角度来看对环境都是有益的。此外，有趣的浸渍工艺提供了一种将功能性材料连接到气凝胶的新方法，而气凝胶具有在许多其他应用中使用的潜力。