Chlorinated volatile organic compounds (CVOCs) and 1,4-dioxane kinetics and equilibrium adsorption studies on selective macrocyclic adsorbents

Abstract

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.

Description

© 2024 cc-by-nc-nd

Keywords

1,4-dioxane, Activated carbon, Biological degradation, CVOCs, Linear isotherms, Partition coefficient, Rapid adsorption, Res-TFN, Selective adsorption, TCE, β-CD-TFN

Citation

Abaie, E., Kumar, M., Garza-Rubalcava, U., Rao, B., Sun, Y., Shen, Y., & Reible, D.. 2024. Chlorinated volatile organic compounds (CVOCs) and 1,4-dioxane kinetics and equilibrium adsorption studies on selective macrocyclic adsorbents. Environmental Advances, 16. https://doi.org/10.1016/j.envadv.2024.100520

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