A DFT study on the adsorption of benzodiazepines to vermiculite surfaces

Abstract

Widespread use of pharmaceuticals such as benzodiazepines has been resulting over the last decades in the dissemination of residues of these compounds in the environment, and such fact has been raising increasing concern. The generally low efficiencies of conventional wastewater treatment processes for the removal of this type of pollutants demands for the development of alternative or complementary water and wastewater treatment technologies, among which adsorption processes have been gaining popularity, provided that cheap efficient adsorbents are found. Clay materials have been one of the popular choices in this regard. In the present study, quantum chemical calculations have been performed by periodic DFT using the projector augmented-wave (PAW) method to characterize the interactions of two benzodiazepine molecules, alprazolam and diazepam, with a surface of clay mineral, vermiculite. It was observed that both molecules interact strongly with the vermiculite surface, both through a water-bridge binding and by cation-bridge provided by the exchangeable Mg 2+ cations of the vermiculite surface. The results point to an interesting potential of vermiculite to be used efficiently as filter medium to remove these pollutants from water and wastewater.

Determination of adsorptive properties of expanded vermiculite for the removal of C. I. Basic Red 9 from aqueous solution: Kinetic, isotherm and thermodynamic studies

“…The use of vermiculite as an adsorbent has been studied for the removal of Hg(II) (Do Nascimento and Masini, 2014), Cr(III) (Badawy et al, 2010;Sis and Uysal, 2014), Cu(II) (Badawy et al, 2010), Pb(II) (Hongo et al, 2012;Sis and Uysal, 2014), Zn(II) (Sis and Uysal, 2014), Cs (Suzuki et al, 2013), Ag(I) (Sari and Tüzen, 2013), Cr(VI) (Dultz et al, 2012), Cd(II) (Panuccio et al, 2009), mineral and canola oils (Mysore et al, 2005), phthalate (Wen et al, 2013), basic cationic dye (Choi and Cho, 1996), herbicides 2,4-D, diuron, alachlor, metolachlor and triazine (de Rezende et al, 2011), dibenzothiophene (Froehner et al, 2010), benzodiazepine (Carvalho et al, 2014) and cationic surfactant cetylpyridinium chloride (Tarasevich et al, 2013) from aqueous solution. Although there are many works published about the adsorption of metal ions and organic compounds onto vermiculite, only one study has been carried out to determine the dye adsorption properties of vermiculite.…”

Theoretical study on the adsorption of benzylpenicillin molecule onto vermiculite surface

“…The interaction energies of these complexes are less negative than those of some investigated systems due to the additional contribution of Mg‧‧‧Cl and Mg‧‧‧N interactions. [8,11] Accordingly, interaction of vermiculite surface with benzylpenicillin is weaker than that with chloramphenicol or benzodiazepines.…”

“…Microscopic perspectives (atomic, molecular levels) to phenomena, and processes taking place can be provided or understood. [8,9] In previous experimental and modeling reports on adsorption of organic compounds, especially for antibiotics in wastewater resources, nature and role of interactions formed on surfaces have not been yet elucidated in detail. Moreover, experimental and theoretical studies on adsorption of antibiotic molecules onto vermiculite surface have not been observed clearly.…”

“…Moreover, experimental and theoretical studies on adsorption of antibiotic molecules onto vermiculite surface have not been observed clearly. [4,5,8,10] Hence, in the present work, with the aim to understand about adsorption process, origin and role of interactions, we investigate the adsorption of BP molecule on vermiculite surface using computational chemistry and modeling approaches.…”

Chemisorption of Enrofloxacin on Rutile-Tio2 (110) Surface: A Theoretical Investigation

“…The interaction energies of P1 and P2 configurations are -55.6 and -54.9 kcal.mol -1 , respectively (cf. Table 2) The deformation energy is a characteristic parameter for evaluating the ability of separating the substrate and the surface from its stable configuration [17]. As tabulated in Table 2, these energy values for TiO 2 surface are larger than that for ENR molecule.…”