Centre for Catalysis Research and Innovation, Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Chem Rev. 2021 Jul 14;121(13):7280-7345. doi: 10.1021/acs.chemrev.0c00762. Epub 2021 May 11.
Carbon capture from large sources and ambient air is one of the most promising strategies to curb the deleterious effect of greenhouse gases. Among different technologies, CO adsorption has drawn widespread attention mostly because of its low energy requirements. Considering that water vapor is a ubiquitous component in air and almost all CO-rich industrial gas streams, understanding its impact on CO adsorption is of critical importance. Owing to the large diversity of adsorbents, water plays many different roles from a severe inhibitor of CO adsorption to an excellent promoter. Water may also increase the rate of CO capture or have the opposite effect. In the presence of amine-containing adsorbents, water is even necessary for their long-term stability. The current contribution is a comprehensive review of the effects of water whether in the gas feed or as adsorbent moisture on CO adsorption. For convenience, we discuss the effect of water vapor on CO adsorption over four broadly defined groups of materials separately, namely (i) physical adsorbents, including carbons, zeolites and MOFs, (ii) amine-functionalized adsorbents, and (iii) reactive adsorbents, including metal carbonates and oxides. For each category, the effects of humidity level on CO uptake, selectivity, and adsorption kinetics under different operational conditions are discussed. Whenever possible, findings from different sources are compared, paying particular attention to both similarities and inconsistencies. For completeness, the effect of water on membrane CO separation is also discussed, albeit briefly.
从大型源和环境空气中捕获碳是遏制温室气体有害影响的最有前途的策略之一。在不同的技术中，CO 吸附因其低能量要求而受到广泛关注。考虑到水蒸气是空气中普遍存在的成分，并且几乎存在于所有富含 CO 的工业气流中，了解其对 CO 吸附的影响至关重要。由于吸附剂种类繁多，水在 CO 吸附中起着从严重抑制剂到优秀促进剂的多种不同作用。水也可能会提高 CO 捕获的速率，或者产生相反的效果。在含有胺的吸附剂存在的情况下，水甚至是其长期稳定所必需的。本贡献是对水（无论是在气体进料中还是作为吸附剂水分）对 CO 吸附的影响的综合综述。为方便起见，我们分别讨论了水蒸气对四类广义定义的材料（即(i)物理吸附剂，包括碳、沸石和 MOF，(ii) 胺功能化吸附剂，和(iii) 反应性吸附剂，包括金属碳酸盐和氧化物）上 CO 吸附的影响。对于每一类，讨论了在不同操作条件下湿度水平对 CO 吸收、选择性和吸附动力学的影响。只要有可能，就会比较来自不同来源的发现，特别注意相似之处和不一致之处。为了完整性，还讨论了水对膜 CO 分离的影响，尽管只是简要讨论。
