Department of Building Science, Tsinghua University, Beijing, 100084, China; Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Beijing, 100084, China.
School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing, 100044, China.
Environ Res. 2021 Jan;192:110218. doi: 10.1016/j.envres.2020.110218. Epub 2020 Sep 24.
Adsorption has been used widely to remove indoor volatile organic compounds (VOCs). However, the large diffusion resistance inside traditional granular adsorbents renders a low VOC adsorption rate. This study proposes a modified method to achieve the rapid diffusion into the adsorbent during the initial adsorption period. A thin and flexible adsorption board with a layer of adsorbent coated on a heating film was prepared for in-situ adsorption and regeneration. Then, regular, vertical macro-channels through the adsorption board were fabricated by laser drilling to enhance mass transfer inside the board. Experimental results demonstrated that after modification, the penetration times for formaldehyde and xylene extended from 3.8 to 6.2 h, and from 62 to 99 h, respectively. The effective adsorption capacity of the modified board had increased by a multiple of two for formaldehyde and 1.8 for xylene. A mathematical model was developed and experimentally validated to evaluate the modification effect for more adsorbent-pollutant pairs. The results showed that the amplification of effective adsorption capacity was positively correlated with the Da/(K·De) parameter; this is the diffusion resistance ratio prior to and following the modification. A spectrogram of adsorbent-pollutant pairs was plotted to guide the modification. This simple macro-channel modification of the adsorption board may be used as an alternative design for adsorption applications in indoor air purification.
吸附广泛应用于去除室内挥发性有机化合物（VOCs）。然而，传统颗粒状吸附剂内部的大扩散阻力导致 VOC 吸附速率低。本研究提出了一种改进方法，在初始吸附期实现快速扩散到吸附剂中。制备了一种带有加热膜的薄而灵活的吸附板，在加热膜上涂覆有一层吸附剂，用于原位吸附和再生。然后，通过激光钻孔在吸附板上制造了规则的、垂直的宏观通道，以增强板内的传质。实验结果表明，经过改性后，甲醛和二甲苯的穿透时间分别从 3.8 小时延长到 6.2 小时和从 62 小时延长到 99 小时。对于甲醛和二甲苯，改性板的有效吸附容量分别增加了两倍和 1.8 倍。建立了一个数学模型，并进行了实验验证，以评估更多吸附剂-污染物对的改性效果。结果表明，有效吸附容量的放大与 Da/（K·De）参数呈正相关；这是修改前后的扩散阻力比。绘制了吸附剂-污染物对的光谱图，以指导修改。这种简单的吸附板宏观通道改性可以作为室内空气净化中吸附应用的替代设计。
