Contents lists available at ScienceDirect Applied Clay Science journal homepage: www.elsevier.com/locate/clay Research paper Wastewater treatment test by removal of the sulfamethoxazole antibiotic by a calcined layered double hydroxide El Hassane Mourid a , Mohamed Lakraimi a, ⁎ , Lhaj Benaziz a , El Hassan Elkhattabi a , Ahmed Legrouri b a Physical Chemistry of Materials Team, Cadi Ayyad University, Marrakech, Morocco b International University of Grand Bassam, Grand-Bassam, Côte d'Ivoire ARTICLE INFO Keywords: Calcined layered double hydroxide Sulfamethoxazole Antibiotic Removal Intercalation Reconstruction ABSTRACT In this study, we investigated the removal of the sulfamethoxazole drug (SMX) by calcined layered double hydroxides (CLDHs) at 500 °C. The characterization of the fresh CLDH solids and after removal of SMX, by X-ray diffraction, infrared spectroscopy and scanning electron microscopy, shows that the removal is carried out by reconstruction of LDH phases intercalated by SMX via the memory effect of mixed oxides. The thermodynamic parameters indicate that the adsorption is governed by physisorption. The removal capacity of SMX by CLDHs, under optimal conditions, reaches 4314 mg/g with an SMX/CLDH mass ratio of 1.6 and the elimination rate reaches 93%. This result is a good sign for fighting the development of bacterial resistance to such antibiotics because the quantity that may remain in natural environments is very low. Recycling of the intercalated phases remains efficient after six cycles. 1. Introduction The presence of micropollutants in aquatic environments constitutes a major problem for aquatic ecosystems, leading to an increase in the rate of waterborne diseases. The World Health Organization (WHO) reported that > 80% of these diseases in developing countries are linked to poor water quality, resulting in about 30% mortality (Jensen, 2009). Emerging micropollutants include pharmaceuticals that have attracted the attention of the global scientific community for several years. Many reports on the occurrence, effects and risks of these com- pounds have been exposed for sensitization to their toxicity (Kummerer, 2009). In addition, these potential pollutants are sometimes directly emitted into watercourses without effluent treatment. The sulfamethoxazole (SMX) belongs to the family of sulphonamide drugs. It is commonly used to treat digestive infections, typhoid fever and certain bronchopulmonary infections as well as urinary tract in- fections in humans and animals. It prevents the formation of dihy- drofolate acid, which is needed for bacteria to survive (Fernández et al., 2014), but some studies have shown a relatively high incidence of bacterial resistance to this antibiotic (Trovo et al., 2009). According to a study carried out in 2009 in Morocco (El Bakkouri et al., 2009) on the resistance of uropathogenic Escherichia coli (E. coli) to antibiotics, 62.4% of the 799 strains of E. coli were resistant to ampicillin, 43.9% to trimethoprim/sulfamethoxazole and 10.4% to fluoroquinolones. The analysis of the evolution of these resistances between 1999 and 2004 showed a significant increase in the resistance to ampicillin and fluoroquinolones, particularly in the 15 to 65 year-old persons. In contrast, the resistance to trimethoprim/sulfamethoxazole did not show significant growth, compared to the IMS (Intercontinental Medical Statistics) data, despite the high consumption of antibiotics. Different methods have been used in recent years to eliminate the pollutants (Sureshkumar and Namasivayam, 2008; Abaamrane et al., 2012; Alventosa-Delara et al., 2014; Ghaedi et al., 2015). Adsorption is one of the most common treatment processes in water treatment and has become a method of choice because it is very effective and easy to use (Crini, 2006; El Gaini et al., 2009; Yasin et al., 2010). LDHs, also known as hydrotalcite-like compounds or anionic clays, and their calcined products (CLDHs), have been widely used as pollu- tants adsorbents (You et al., 2002; Li et al., 2005; Legrouri et al., 2005; Ni et al., 2007). These are layered materials with a net positive charge on the layer, due to partial substitution of divalent by trivalent cations. This charge is balanced by exchangeable charge compensating organic or inorganic anions, which are present in the interlayer space with water molecules (Ni et al., 2007). The materials can be represented by the general formula: − − [M M (OH) ](A ) . mH O II 1 x III x 2 n x/n 2 https://doi.org/10.1016/j.clay.2018.11.005 Received 20 June 2018; Received in revised form 18 September 2018; Accepted 5 November 2018 ⁎ Corresponding author. E-mail address: mlakraimi@yahoo.fr (M. Lakraimi). Applied Clay Science 168 (2019) 87–95 0169-1317/ © 2018 Published by Elsevier B.V. T