Effects of pH and Cationic and Nonionic Surfactants on the Adsorption of Pharmaceuticals to a Natural Aquifer Material

Abstract

A wide range of pharmaceutical compounds have been identified in the environment, and their presence is a topic of growing concern, both for human and ecological health. Adsorption to aquifer materials and sediments is an important factor influencing the fate and transport of pharmaceutical compounds in the environment. Surfactants and other amphiphiles are known to influence the adsorption of many compounds and may be present in the environment from wastewaters or other sources. The work described here examines the adsorption of four pharmaceutical compounds, acetaminophen, carbamazepine, nalidixic acid, and norfloxacin, in the presence of a natural aquifer material. Adsorption was studied as a function of pH and in the presence and absence of two surfactants, cetylpyridinium chloride (CPC), a cationic surfactant, and Tergitol NP9, an ethoxylated nonionic surfactant. In the absence of surfactants, results indicate a 1-2 orders of magnitude variation in adsorption affinity with changing pH for each of the two quinolone pharmaceuticals (nalidixic acid and norfloxacin) but no measurable adsorption for carbamazepine or acetaminophen. In the presence of surfactants, adsorption of acetaminophen and carbamazepine was enhanced to extents consistent with compound hydrophobicity, while adsorption of nalidixic acid and norfloxacin was not. At high pH values, the anionic species of nalidixic acid exhibited enhanced adsorption in the presence of the cationic surfactant, CPC.

Antibiotic resistance genes occurrence and bacterial community composition in the Liuxi River

“…In sediment samples collected from the Yellow River, Hai River, Liao River, oxytetracycline had the concentrations as high as 653 µg kg −1 , sulfamethoxazole had not detected at all, and norfloxacin had the highest concentrations of up 5770 µg kg −1 among the fluoroquinolones (ciprofloxacin, norfloxacin, and enrofloxacin) analyzed. Those results were different from the results from the present study, supporting that the distribution of antibiotics in the environment are dependent on the antibiotic consumption, use patterns, antibiotic partition characteristics and chemical stability (Hari et al, 2005). The waste effluents containing antibiotics from animal feedlots and chemical plants (Figure 1) were probably responsible for the antibiotic pollution in the Liuxi River.…”

Kinetic Study of Denatonium Sorption to Smectite Clay Minerals

“…Generally, an environmental assessment of chemical fate and transport is determined by the speciation, phase (i.e., solid, liquid, or gas), and interaction(s) of the material with environmental matrices (air, soil, and ground water). Since concerns exist about DB contaminating ground water, the starting point in any discussion must include a study of DB-soil solution interactions (Gorman-Lewis and Fein, 2004;Hari et al, 2005).…”

Sorption of Enrofloxacin and Ciprofloxacin in Agricultural Soils: Effect of Organic Matter

“…Other antimicrobial families have also displayed similar behaviour, such as tetracyclines (Teixido et al 2012). Several authors have attributed this sorption behaviour to cooperative forces among sorbed molecules (Hinz 2001;Groisman et al 2004). By contrast, unamended soil S2 isotherms for both FQs were nearly linear (Table 2; N values close to unity) in the concentration range studied (Figure 2).…”

“…Nevertheless, the contribution of partitioning in the sorption of polar ionizable antimicrobials to the hydrophobic fractions present in humic-like substances has proven to be almost negligible (Tolls 2001;Gu et al 2007). By contrast, cation-exchange mechanisms are thermodynamically more favourable than hydrophobic partition processes (Horvath et al 1976). Although both FQs are mainly zwitterionic (electrically neutral), their negative-and positivecharged groups (the carboxyl and amino groups, respectively; Figure 1) can be spatially separated enough to electrostatically interact with different charged surface functional groups (Hyun et al 2003).…”