Macroscopic and molecular approaches of enrofloxacin retention in soils in presence of Cu(II)

Adsorption of enrofloxacin in presence of Zn(II) on a calcareous soil

“…Enrofloxacin retention on a calcareous soil was fully discussed in a previous study conducted in our laboratory (Graouer-Bacart et al, 2013). To summarize the major results highlighted in this study, the adsorption equilibrium time corresponded to 16 h. ENR adsorption onto the soil showed strong pH dependence attributed to a combination of pH-dependent speciation of ENR and soil surface charges illustrating the influence of electrostatic interactions in the sorption process.…”

“…The suspensions were stirred until the adsorption equilibrium was reached (time predetermined by kinetic studies). The pH of the sample is one of the most important factors affecting ENR retention (Yan et al, 2012;Graouer-Bacart et al, 2013). Since the addition of antibiotic and metal solutions can modify the soil solution pH, the pH value was controlled and adjusted to 8.1 (soil pH value) if needed by adding 0.1 mol L À 1 KOH.…”

“…Once ENR has entered the environment, its sorption on soils is one of the key processes governing its mobility and the characterization of the retention mechanisms is essential for assessing its fate in soil and water systems. The extent of ENR adsorption is related to various soil properties such as content and type of clay minerals, cation exchange capacity, pH or ionic strength (Essington et al, 2010;Figueroa-Diva et al, 2010;Yan et al, 2012;Graouer-Bacart Leal et al, 2013). At environmentally relevant concentrations, the retention of pharmaceuticals in soils is quantified using the adsorption coefficient K d which describes a constant partition of the compound between the solid and the liquid phases.…”

“…Metal cations are naturally present in soils or originate from industrial wastes and various agricultural treatments, and can significantly modify antibiotic sorption properties (Jia et al, 2008;Pei et al, 2010;Pérez Guaita et al, 2011;Graouer-Bacart et al, 2013). Therefore, the simultaneous presence of ENR and metal cations in soils is very likely.…”

“…However, only few studies investigated the sorption properties of fluoroquinolones and particularly ENR in presence of metal cations. It was shown that the retained fluoroquinolone amounts onto the soil surface increased with the copper concentration due a "bridge" effect of Cu(II) and the formation of a ternary surface complex (Pei et al, 2010;Pérez Guaita et al, 2011;Graouer-Bacart et al, 2013). Thus, data concerning the speciation and the reactivity of fluoroquinolones in presence of metal cations at the solid-water interface are limited leading to a lack of knowledge.…”