Available online at www.sciencedirect.com Journal of Membrane Science 309 (2008) 94–101 Removal of hormones and antibiotics by nanofiltration membranes Ismail Koyuncu a,∗ , Osman A. Arikan a,b , Mark R. Wiesner c , Clifford Rice b a Department of Environmental Engineering, Istanbul Technical University, Maslak, Istanbul 34469, Turkey b USDA-ARS, Environmental Management and Byproduct Utilization Laboratory, Beltsville, MD 20705, USA c Department of Civil and Environmental Engineering, Duke University, P.O. Box 90287, Durham, NC 27708-0287, USA Received 4 July 2007; received in revised form 2 October 2007; accepted 9 October 2007 Available online 16 October 2007 Abstract The removal of several hormones and antibiotics by nanofiltration membranes was studied in mixed solutions. The effects of solution chemistry, organic matter and salinity were investigated on the rejection of tetracycline’s and sulfanamides and selected hormones and their adsorption on membranes. Tetracyclines were observed to have a high adsorptive affinity for the membrane. Almost 80% of chlorotetracycline was adsorbed on the membrane surface compared with 50% for doxcycline while the adsorption rates for hormones were lower than those obtained for tetracyclines. Addition of calcium, organic matter and salinity had an influence on the rejections. Rejection of sulfanamides was low compared to hormones and tetracyclines. Addition of antibiotics to hormone solution increased the hormone rejections while almost complete rejections were observed for tetracyclines. © 2007 Elsevier B.V. All rights reserved. Keywords: Nanofiltration; Hormone; Antibiotics; Adsorption 1. Introduction There is a growing awareness of the importance of trace levels of organic compounds as contaminants originating from indus- trial, agricultural, medical and domestic uses. Compounds used in personal care products, pharmaceuticals and other consum- ables as well as hormones may enter aquatic environments after passing through wastewater treatment plants, which often are not designed to remove these chemicals [1,2]. In addition, vet- erinary pharmaceuticals and growth promoters used in animal husbandry may be released directly to the environment with ani- mal wastes through overflow or leakage from storage facilities or land application [1,3]. As early as 1973, Norpoth et al. [4] indicated that the use of contraceptives may cause severe long-term problems due to the high persistence and biological activity of those com- pounds in the environment. Evidence now exists that hormones and pharmaceuticals are widespread in effluents of sewage treatment plants [5]. One of the first results concerning environ- mental occurrence of pharmaceuticals was reported by several ∗ Corresponding author. Tel.: +90 212 285 3789; fax: +90 212 285 6545. E-mail address: koyuncu@itu.edu.tr (I. Koyuncu). researchers [6–8] who detected clofibric acid in treated sewage in the US. Further studies were obtained in Great Britain [9] and Canada [10]. However, extensive investigation of the occurrence of hormones and pharmaceuticals in the environment began in the 1990s, when the first analytical methods were developed allowing for the determination of pharmaceuticals in aqueous matrices [11]. Many scientific reports have documented the environmental and health implications of hormones and antibiotics. Although, the concentrations of hormones and antibiotics in drinking water and wastewaters are at low levels (ng/l), these compounds may accumulate in animals. Several studies have suggested a link between environmental exposures to hormones and deteriorat- ing trends in human health including decreases in male sperm count; increase in testicular, prostate, ovarian and breast can- cer; and reproductive malfunctions [12–17]. Desbrow et al. [18] found levels of hormones in domestic effluent samples at con- centrations up to 80 ng/l. A recent study conducted by the US Geological Survey on fresh water resources that receive efflu- ents from across the US showed the occurrence of estradiol and estrone in approximately 7–10% of the water samples with max- imum concentrations up to 93 and 112 ng/l, respectively [1]. Estradiol concentrations ranging from 6 to 66 ng/l have been found in ground water [19] and in the South Nevada water sys- 0376-7388/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.memsci.2007.10.010