通常发现氯化的挥发性有机化合物(CVOCs)与1,4-二恶烷组合,1,4-二恶烷用作溶剂稳定剂。分离这些化合物将是合乎需要的,因为1,4-二恶烷的生物降解遵循需氧途径,而需要厌氧条件来生物降解CVOCs。传统的吸附剂,如活性炭(AC)和碳质树脂对1,4-二恶烷和CVOCs具有很高的吸附能力,但缺乏选择性,限制它们用于分离(Liu等人。,2019)。在目前的工作中,两种大环吸附剂,β-CD-TFN和Res-TFN,检查了在1,4-二恶烷存在下氯化乙烯的选择性吸附。两种吸附剂均表现出CVOCs的快速吸附和1,4-二恶烷的最小吸附。Res-TFN对CVOCs的吸附能力高于β-CD-TFN(测得的线性分配系数,对于1,1,1,DCE,Kd2140-9750L·kg-1与192-918L·kg-1,顺式-1,2-DCE和TCE,分别),并且对CVOCs具有高度选择性(1,4-二恶烷的TCEKd〜117Kd)。相比之下,TCE和1,4-二恶烷在AC上的吸附在100µg·L-1处大约相等,TCE在Res-TFN上的吸附约为1/3。Res-TFN的更大吸附和选择性表明,它可以用作选择性吸附剂将CVOCs与1,4-二恶烷分离以允许单独的生物降解。
Chlorinated volatile organic compounds (
CVOCs) are often found in combination with 1,4-dioxane which has been used as a solvent stabilizer. It would be desirable to separate these compounds since biodegradation of 1,4-dioxane follows an aerobic pathway while anaerobic conditions are needed for biodegrading CVOCs. Conventional adsorbents such as activated carbon (AC) and carbonaceous resins have high adsorption capacities for 1,4-dioxane and
CVOCs but lack selectivity, limiting their use for separation (Liu et al., 2019). In the current work, two macrocyclic adsorbents, β-CD-TFN and Res-TFN, were examined for selective adsorption of chlorinated ethenes in the presence of 1,4-dioxane. Both adsorbents exhibited rapid adsorption of the
CVOCs and minimal adsorption of 1,4-dioxane. Res-TFN had a higher adsorption capacity for
CVOCs than β-CD-TFN (measured linear partition coefficient, Kd 2140 -9750 L⋅kg-1 versus 192-918 L⋅kg-1 for 1,1, DCE, cis-1,2-DCE and TCE, respectively) and was highly selective for
CVOCs(TCE Kd ~117 Kd for 1,4-dioxane). By comparison, TCE and 1,4-dioxane adsorption on AC was approximately equal at 100 µg⋅L-1 and approximately 1/3 of the adsorption of TCE on the Res-TFN. The greater adsorption and selectivity of Res-TFN suggest that it can be used as a selective adsorbent to separate CVOCs from 1,4-dioxane to allow separate biodegradation.