Jia Lijuan, Niu Ben, Jing Xiaoxia, Wu Yangfang
Department of Applied Chemistry, Yuncheng University, Yuncheng, China.
Department of Logistics, Yuncheng University, Yuncheng, China.
J Air Waste Manag Assoc. 2022 Feb;72(2):176-186. doi: 10.1080/10962247.2021.2011477. Epub 2022 Jan 10.
Water vapor has been one of the vital problems in purification of volatile organic compounds. In this study, the adsorption-desorption equilibrium of water vapor were conducted at 298, 308, 318, and 328 K on three adsorbents: hypercrosslinked polymeric adsorbents (HPA), activated carbon fiber (ACF) and granular activated carbon (GAC). The obtained isotherms were type V and the adsorption capacity at the same condition was: GAC>ACF>HPA. cluster formation induced micropore filling (CIMF) model was adopted to fit the adsorption isotherms and the fitting parameters showed that adsorption capacities of water vapor on micropores and functional groups had a negative logarithmic linear relationship with temperature. The existence of functional groups could weaken the negative influence of temperature on the water adsorption performance, while the influence of temperature had negligible relationship with microporous volume. The hysteresis loops at different temperatures on three adsorbents had similar shape, the size of which were also: GAC>ACF>HPA. They mainly occurred in micropore adsorption, but their size had positive relationships with both functional groups and microporous volume. The hysteresis became smaller along with the increase of temperature, closely related with the stability of water clusters. In conclusion, temperature, functional groups and porous structure played crucial roles for water vapor adsorption and the formation of hysteresis.: Water vapor is one of the vital influence for VOCs recovery, so studying the adsorption mechanism of water vapor is important to weaken its negative effect. Adsorption capacities of water vapor on both micropores and functional groups had a negative logarithmic linear relationship with temperature. The existence of functional groups could weaken the negative influence of temperature on the water adsorption performance, while the influence of temperature had negligible relationship with microporous volume. The hysteresis loops on three adsorbents mainly occurred in micropore adsorption, but their size had positive relationships with both functional groups and microporous volume.
水蒸气一直是挥发性有机化合物净化过程中的关键问题之一。在本研究中，在298、308、318和328 K温度下，对三种吸附剂进行了水蒸气的吸附-解吸平衡实验，这三种吸附剂分别是：超交联聚合物吸附剂（HPA）、活性炭纤维（ACF）和颗粒活性炭（GAC）。所得到的等温线为V型，且在相同条件下的吸附容量为：GAC>ACF>HPA。采用簇形成诱导微孔填充（CIMF）模型对吸附等温线进行拟合，拟合参数表明，水蒸气在微孔和官能团上的吸附容量与温度呈负对数线性关系。官能团的存在可减弱温度对水吸附性能的负面影响，而温度的影响与微孔体积的关系可忽略不计。三种吸附剂在不同温度下的滞后回线形状相似，其大小也为：GAC>ACF>HPA。它们主要发生在微孔吸附中，但其大小与官能团和微孔体积均呈正相关。随着温度升高，滞后现象变小，这与水簇的稳定性密切相关。总之，温度、官能团和多孔结构对水蒸气吸附及滞后现象的形成起着关键作用。水蒸气是影响挥发性有机化合物回收的关键因素之一，因此研究水蒸气的吸附机理对于减弱其负面影响具有重要意义。水蒸气在微孔和官能团上的吸附容量与温度呈负对数线性关系。官能团的存在可减弱温度对水吸附性能的负面影响，而温度的影响与微孔体积的关系可忽略不计。三种吸附剂上的滞后回线主要发生在微孔吸附中，但其大小与官能团和微孔体积均呈正相关。
