Adsorption of Dibenzothiophene by Vermiculite in Hydrophobic Form, Impregnated with Copper Ions and in Natural Form

Abstract

The adsorption capacity of vermiculite, a natural clay, for removing dibenzothiphene (DBTP) from water solutions was investigated. DBTP is an organic compound with sulfur, commonly found in fossil fuels and coal. This compound can also be found in the environment due accidental spills of oil and derivatives. Due to its structure and physicalchemical properties it is considered a persistent compound. Vermiculite (VT) was used as an adsorbent in its natural form, impregnated with copper ions (Cu-VT), and hydrophobically modified (HDTMA-VT) by replacement sodium cations by hexadecyltrimethyl ammonium ion. The results showed that DBTP was adsorbed in considerable amounts by HDTMA-VT; however, the Cu-VT adsorbed DBTP in some proportions of HDTMA-VT. Because of the presence of sulfur atoms in the structure of the molecule, π complexation can be observed. The adsorption isotherms were treated by the Freundlich equation. The values of K f are similar to Cu-VT and HDTMA-VT, showing that the adsorption may be either through hydrophobic interactions or interactions through the formation of π complex. Meanwhile, the results with the VT (natural form) showed a much smaller value of K f . It is believed, compared with the literature, and because of the chemical composition of the vermiculite, that the adsorption mechanism is also conducted by π complexation, considering the absence of organic carbon content.

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.…”

A Catabolic Activity of Sphingomonas wittichii RW1 in the Biotransformation of Carbazole

“…Carbazole is used widely in the synthesis of dyes, pharmaceuticals, and plastics is used to make photographic plates that are sensitive to ultraviolet light and is used in the manufacture of reagents, explosives, insecticides, lubricants, and rubber antioxidants. Environmentally, carbazole is often found in soil, groundwater, and rivers contaminated by petroleum and wood-preserving wastes or chemical industry pollution, and it is a suspected carcinogen (Froehner et al 2010;King and Barker 1999;Mueller et al 1989).…”

Characterization and Modification of a Clay Mineral Used in Adsorption Tests

“…The use of expanded vermiculite as a supporting agent to wastewater treatment has been presented in the literature. The use of expanded vermiculite as adsorbent has been particularly related to the removal of dyes, hydrocarbons and other hydrophobic substances [16]- [22].…”