Ag and CuO nanoparticles decorated on graphene oxide/activated carbon as a novel adsorbent for the removal of cephalexin from water

Abstract As a consequence of the inadequate disposal of pharmaceutical products and a residual portion that is not absorbed by the organism and is disposed into domestic sewage, antibiotics have been found in water resources. This results in serious problems for the environment and for human health, thus, efficient methods to remove these compounds from aqueous effluents are necessary. In this study, carbon with silver and copper oxide nanoparticles supported in activated carbon (CA-NPsAg/CuO), silver and copper oxide nanoparticles supported in graphene (OGR-NPsAg/CuO), and graphene oxide impregnated with silver and copper oxide nanoparticles supported in activated carbon (CA-OGR-NPsAg/CuO) to remove the cephalexin antibiotic in aqueous solution was investigated. These adsorbents were characterized through scanning electron microscopy and zeta potential. Adsorption equilibrium data were obtained for those three adsorbents at pH 6.7 (natural) and temperature 25 ∘C and the isotherm models of Langmuir, Freundlich, Sips, Sigmoidal Langmuir, and Dubin-Astakov were investigated to describe the data. Langmuir model was the one that better described the experimental equilibrium data for the adsorbent CA-OGR-NPsAg/CuO, while for the adsorbent CA-NPsAg/CuO, it was the Sips model, and Freundlich model for the adsorbent OGR-NPsAg/CuO. At low cephalexin concentration levels, the better performance regarding removal capacity was the adsorbent CA-NPsAg/CuO.The maximum adsorption capacity of each adsorbent was 756.8 mg g−1, 557.7 mg g−1, and 95.82 mg g−1 for CA-OGR-NPsAg/CuO, CA-NPsAg/CuO, and OGR-NPsAg/CuO, respectively. The knowledge about those studied adsorbents can improve the treatment of water contaminated with cephalexin antibiotic.