Over the past few decades, occurrence of organic micro-pollutants such as pharmaceuticals in the aquatic ecosystems has been considered as a major environmental and health issue globally. Pharmaceuticals have become chemicals of emerging concern to the public because of their potential to reach drinking water. A novel Polyaniline/humic acid (PA/AH) composite was synthesized and investigated for adsorption of Metronidazole antibiotics (MTZ) from aqueous solutions. The nature and morphology of synthesized adsorbent were characterized by scanning electron microscope, Surface adsorption (BET). Batch experiments were performed to study the influence of various experimental parameters such as contact time, initial concentration of the MTZ and temperatures at fixed solution pH and adsorbent dosage. A comparison of kinetic models was evaluated for the pseudo-first-order, pseudo-second-order, Elovich, intraparticle diffusion and Bangham's kinetics models. The experimental data fitted very well the pseudo second-order kinetic model and also followed by intra-particle diffusion model; whereas diffusion is not only the rate-controlling step, and likely that both adsorption steps, bulk and intra-particle diffusion, control the rate of adsorption process. The results show that the sorption capacity increases with increase in solution temperature from 10 to 55 o C. As adsorption capacity of 42.2 to 49.95 mg/g increases when the temperature increases from 10 to 55 o C. The developed polyaniline nanocomposites in this study have considerable potential for the removal of MTZ and could be considered as a promising adsorbent for the removal of other antibiotics also from aqueous solutions.

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Antibiotics as emerging contaminants are of global concern due to the development of antibiotic resistant genes potentially causing superbugs. The inefficiency of conventional purification processes in the complete removal of antibiotics increases the resistance of microorganisms in humans and the environment, hence new and low-cost technology is needed. Adsorptive materials have been extensively used for the conditioning, remediation and removal of inorganic and organic hazardous materials. Zirconium oxide is a widely used inorganic material which is chemically stable, non-toxic and not soluble in water. Thus it could be an attractive candidate for drinking water puri? cation. In this study, Zirconium Oxide Nanoparticles (ZrO 2 NP)has been used as the adsorbent for the possibility of removing Cipro? oxacin (CIP) from aqueous solution using the batch adsorption technique under different conditions of initial CIP concentration (25, 50, 75, 100 mg/L), adsorbent dose (0.1, 0.2, 0.3, 0.5, 0.7, 0.9 and 1 g/L) and contact time (10-150 min). The percentage of CIP adsorbed increased with increase in the mass of the adsorbent dose from 0.1 to 1 g/L. Kinetics study for sorption was evaluated using diffusion models, pseudo-first order kinetic and pseudo-second order kinetic. Results show that pseudo second-order kinetic model gave the best description for the adsorption process. The experiments showed that the highest removal rate was 96.5% under optimal conditions. The sorption of CIP on ZrO 2 NP was rapid during the first 30 min and the equilibrium attained within 75 min. The results suggest that ZrO 2 NPcould be a good candidate to remove CIP from wastewater containing different amounts of antibiotic.