Cyclodextrin-enhanced 1,4-dioxane treatment kinetics with TCE and 1,1,1-TCA using aqueous ozone

An integrated approach using ozone nanobubble and cyclodextrin inclusion complexation to enhance the removal of micropollutants

“…Notably, the absorbance of O3 decreased with increasing concentration of HPβCD, while the fluorescence intensity of 4-chlorophenol increased. These two aspects are consistent with previous studies on the formation of inclusion compounds with HPβCD (Khan et al 2019;Faisal et al, 2020). The response of absorbance of O3 was attributed to the high electron density in the cavity of HPβCD, which could cause alteration in the valence electron characteristics in the O3 molecule, an increase in the difference in electron transition energy and a decline in the electron transition probability (Shi and Zhou, 2011).…”

“…The procedures for 1 H NMR and 2D ROESY NMR analyses are described in the Supplementary Material (Text S2). The binding constants of HPβCD-O3 and HPβCD-4-chlorophenol inclusion complexes, indicative of inclusion potential, could be explained by the Benesi-Hildebrand equation (1) (Cai et al, 2015;Khan et al 2019).…”

“…This observation was mainly attributed to the molecular dimensions of the β-CD cavity which could readily form inclusion complexes through host-guest interactions (Szente et al, 2018). Khan et al (2019) reported that significant amounts of O3 and/or contaminants could enter the clathrate cavity and thus enhance their interaction through proximity effects. More importantly, the O3 decay rates (0.19-0.95 h -1 ) in the O3 nanobubble aeration group were 0.49-0.75 times lower, and O3 lifespans (3.5-66 h) were 2.00-9.33 times higher, than those determined from the macrobubble aeration group, at the same HPβCD:O3 molar ratio (Fig.…”

“…According to this concept, Dettmer et al (2017) initially investigated the hydroxypropyl-β-cyclodextrin (HPβCD):O3 clathrate complex as an ozone stabilizer. The addition of HPβCD has been further proven to significantly enhance the ozonation of 1,4-Dioxane, Trichloroethylene and 1,1,1-Trichloroethane (Khan et al 2019). Nevertheless, the molecular structures of the complexes and the dynamics of their formation need further study in order to reveal the underpinning mechanisms.…”

Comparison of Manganese Dioxide and Permanganate as Amendments with Persulfate for Aqueous 1,4-Dioxane Oxidation

“…Degradation and removal of 1,4-D from contaminated water has been demonstrated through application of strong oxidants or advanced oxidation processes (AOP) [1,8,9,13]. The persulfate ion (PS) has been proposed for in-situ chemical oxidation (ISCO) of groundwater plumes because of the increased aqueous solubility and stability advantage PS has over other regularly used AOP oxidants such as catalyzed H 2 O 2 propagation and ozone [14].…”