Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB T6G 2W2, Canada.
Environ Sci Technol. 2012 Aug 7;46(15):8341-50. doi: 10.1021/es3013062. Epub 2012 Jul 16.
In this study, adsorption and desorption of mixtures of organic compounds commonly emitted from automotive painting operations were experimentally studied. A mixture of two alkanes and a mixture of eight organic compounds were adsorbed onto beaded activated carbon (BAC) and then thermally desorbed under nitrogen. Following both adsorption and regeneration, samples of the BAC were chemically extracted. Gas chromatography-mass spectrometry (GC-MS) was used to quantify the compounds in the adsorption and desorption gas streams and in the BAC extracts. In general, for both adsorbate mixtures, competitive adsorption resulted in displacing low boiling point compounds by high boiling point compounds during adsorption. In addition to boiling point, adsorbate structure and functionality affected adsorption dynamics. High boiling point compounds such as n-decane and 2,2-dimethylpropylbenzene were not completely desorbed after three hours regeneration at 288 °C indicating that these two compounds contributed to heel accumulation on the BAC. Additional compounds not present in the mixtures were detected in the extract of regenerated BAC possibly due to decomposition or other reactions during regeneration. Closure analysis based on breakthrough curves, solvent extraction of BAC and mass balance on the reactor provided consistent results of the amount of adsorbates on the BAC after adsorption and/or regeneration.
在这项研究中，实验研究了汽车涂装作业中常见排放的有机化合物混合物的吸附和解吸。两种烷烃的混合物和八种有机化合物的混合物被吸附到珠状活性炭（BAC）上，然后在氮气下热解吸。在吸附和再生后，对 BAC 样品进行化学提取。气相色谱-质谱联用（GC-MS）用于定量分析吸附和解吸气流以及 BAC 提取物中的化合物。一般来说，对于两种吸附质混合物，在吸附过程中，低沸点化合物会被高沸点化合物取代，从而发生竞争吸附。除了沸点之外，吸附质的结构和功能也会影响吸附动力学。在 288°C 下再生三个小时后，正癸烷和 2,2-二甲基丙基苯等高沸点化合物仍未完全解吸，表明这两种化合物导致 BAC 上出现“脚跟”积累。在再生 BAC 的提取物中检测到了混合物中不存在的其他化合物，可能是由于在再生过程中分解或发生其他反应。基于穿透曲线的封闭分析、BAC 的溶剂萃取和反应器的质量平衡，为吸附和/或再生后 BAC 上吸附质的量提供了一致的结果。
