Effect of contact time and the use of hydroxypropyl-β-cyclodextrin in the removal of fluorene and fluoranthene from contaminated soils

Abstract

14Sorption-desorption experiments of fluorene (FLU) and fluoranthene (FLT) in soils 15were carried out and correlated to their removal from aged contaminated soils using 16 aqueous solutions in the absence and in the presence of hydroxypropyl-β-cyclodextrin 17 (HPBCD) as the extraction agent. FLU became more resistant to extraction in aged 18 contaminated soils due to its initial adsorption onto the mineral and amorphous soil 19 organic matter (SOM) domains, sites of lower binding energy from which, due to its 20 small size, it could spread towards the condensed SOM as the contact time increased. 21Therefore, FLU will not be easily desorbed from aged contaminated soils due to 22 physical entrapment mechanisms, even when using HPBCD as extractant, presenting 23 FLU low risks to the environment. On the contrary, FLT was extracted from aged soils 24 in the presence of HPBCD in solutions to a much greater extent than in its absence. Due 25 to its more hydrophobic character FLT sorption in soils was relatively quicker, 26 remaining more or less fixed on hydrophobic sites of the organic matter (OM) with 27 different energies, and therefore the amount of FLT extracted was almost constant for 28 different ageing times. During extraction experiments, the influence of the OM quality 29 of the soils was also highlighted because an inverse proportionality between OM 30 content of soil and extractability of sorbed FLT was observed. It was concluded that 31Preprint submitted to Elsevier 2 soils with lower OM content that had more diagenetically processed OM could block 1 the extraction of FLT more effectively than soils with higher OM content that are less 2 humified. This indicates the need to not only use adsorption-desorption data in 3 contaminant fate and transport models, but also extraction studies in aged contaminated 4 soils and other complementary analytical approaches when assessing soil 5 contamination-related risks. 6 7 8

Clay mineral dependent desorption of pyrene from soils by single and mixed anionic–nonionic surfactants

“…The pyrene removal from kaolin-rich soil was a fast process and over 50% of pyrene were removed at the mass ratio of 7:3 after reaching equilibrium (4 h). A fast initial increase of the percentage of pyrene extracted was followed by a slower increase, as shown in desorption of pyrene from kaolin, which is consistent with the findings of Morillo [43]. Desorption curves of kaolin-rich soil was fitted to a simple firstorder model (R P 0.98) and the plots of desorption of pyrene from kaolin was fitted to a first-order two-compartment model (R P 0.94).…”

Assisted attenuation of a soil contaminated by diuron using hydroxypropyl-β-cyclodextrin and organic amendments

“…These diuron solubility studies in the aqueous phase in the presence of different CDs showed that the best complexation parameters for the formation of CD-diuron water-soluble inclusion complexes were obtained in the case of HPBCD. CDs are considered novel hosts for the complexation of hydrophobic compounds in the environment, including PAHs and pesticides and even some emerging contaminants such as alkylphenols (Morillo et al, 2014;Sánchez-Trujillo et al, 2013). Consequently, the use of CDs can address some of the largest problems facing chemistry, such as the increase of pollution in the environment (Albelda et al, 2012).…”

The Development of a New Complexation Technique of Hydrocortisone Acetate with 2-Hydroxypropyl-β-Cyclodextrin: Preparation and Characterization

“…The calculated K S (1:1) was 484M -1 , which is within the range considered suitable for the formation of stable inclusion complexes 100-5000M -1 [17]. The K S (1:1) calculated by Filipović-Grcić J et al [12] was equal to 466M -1 . The relation between S max = 4.9338mM and S o = 0.0769mM, demonstrated that the increase of HA solubility was on the order of 64 times.…”

“…The HPβCD which is known for its good aqueous solubility and low toxicity [11] and the cost is within the range of common surfactants [12].…”