Sorption of aromatic hydrocarbons onto montmorillonite as affected by norfloxacin

Abstract

a b s t r a c tEffect of norfloxacin (Nor) on the sorption of 1,3-dinitrobenzene (1,3-DNB), and PAHs (naphthalene (NAPH), phenanthrene (PHEN) and pyrene (PYR)) to K + -montmorillonite was studied. Nor suppressed 1,3-DNB sorption due to their competition for the same sorption sites. 1,3-DNB was sorbed on K + -montmorillonite surface via cation-polar interaction and n-electron donor-acceptor interaction. Nor also was sorbed on these sites through cation exchange, cation bridging and/or surface complexation. Nor increased three PAHs sorption on montmorillonite and the enhanced magnitude was positively correlated with the -donor strength of three PAHs. The enhanced sorption of PAHs by Nor was primarily attributed to -interaction between -electron-depleted quinoline ring of Nor and -electron-rich PAHs. Compared with cation (Nor + ) and anion (Nor − ), zwitterion (Nor ± ) of Nor increased PHEN and PYR sorption more pronounced due to additional cation-interaction between the sorbed Nor ± and PAHs. 1 H NMR spectrum provided direct evidence for -and cation-complexation between PAHs and Nor + in solution by ring-current-induced upfield chemical shifts of amino group and methylene group of Nor + .

Adsorption Characteristics of Norfloxacin by Biochar Prepared by Cassava Dreg: Kinetics, Isotherms, and Thermodynamic Analysis

“…A clear different band at around 3400 cm -1 appeared after the contact of NOR with biochars, which could be attributed to the presence of O-H groups. The asymmetric (1600 cm -1 ) and symmetric (1370 cm -1 ) stretching vibrations of COO -were observed due to deprotonation of -COOH group, which was similar to studies obtained for NOR sorption onto montmorillonite (Pei et al 2012). This could be probably caused by electronic induced effects, indicating a possible sorption mechanism involving π-π interactions between the NOR and biochars (Jia et al 2013).…”

Organic xenobiotics removal in constructed wetlands, with emphasis on the importance of the support matrix

“…On the other hand, sorption of polar or ionic pollutants is dominated by electrostatic interactions and ion exchange phenomena. Materials with such characteristics can be found among several types of clays [36,[121][122][123][124][125]. The large majority of organic xenobiotic pollutants are non-polar, although some particular classes like most pharmaceuticals are polar or ionizable [119].…”

“…Electrostatic interactions with the surface and mechanisms such as cation exchange, cation bridging with the surface, surface complexation, and hydrogen bonding seem to be involved in the capture of ionic and polar species from aqueous media [121][122][123][124][125]176]. In addition, the interlayer expandability of many of these minerals and the presence of water molecules associated with exchangeable cations in these interlayers allows the exchange of these hydrated ions with much larger organic molecules and their intercalation between the aluminosilicate layers [123,177,178].…”

“…Some of the most popular types of clay minerals (kaolinite, illite, montmorillonite, vermiculite, sepiolite, bentonite) have been tested to remove by adsorption a variety of organic pollutants such as dyes [182][183][184][185][186][187][188][189][190][191], pesticides [74,[192][193][194][195][196], PAHs [124,189,197], pharmaceuticals [74,75,157,[175][176][177], phenolic compounds [125,174,198] and other aromatics [124,174,189,198]. In the vast majority of these studies the organic substances are removed most commonly from pure water solutions in batch adsorption assays.…”

Horizontal subsurface flow constructed wetland for removal of high-loaded ibuprofen from wastewater under tropical climate

“…The sorptive capacity of substrate should be suitable for the removal of target contaminants from wastewater. Sorption of pollutants onto the surface of substrate involves different mechanisms such as hydrophobic partitioning, electrostatic interaction, van der Waals interaction, ion exchange and surface complexation(Tolls 2001, Haberl et al 2003, Reddy and DeLaune 2008, Pei et al 2012, Dordio and Carvalho 2013. Non-polar organic pollutants can be preferentially adsorbed to the substrate materials which are rich in organic matter such as soil, compost and agricultural wastes through hydrophobic process.…”