REMOVAL OF ISOPROTURON FROM AQUEOUS SOLUTION BY ADSORPTION ONTO A COMMERCIAL ACTIVATED CARBON S. Álvarez-Torrellas, G. Ovejero, A. Rodríguez, J. García Catalysis and Separation Processes, Chemical Engineering Department, Complutense University 28040, Madrid, Spain E-mail: satorrellas@ucm.es Abstract In this research work, the removal of a pesticide, isoproturon, from aqueous solutions by adsorption on granular activated carbon in batch mode and fixed-bed columns operations has been studied. The effect of relevant operation parameters on breakthrough curves as mass of adsorbent (m = 0.1-0.3 g), initial isoproturon concentration (C0 = 50-150 μg.L -1 ) and volumetric flow rate (Q = 2.0-3.0 mL.min -1 ) was studied. Breakthrough times of the column were found to increase with an increasing in the value of the mass of adsorbent, and with a decrease in the initial concentration and flow rate. The adsorption parameters of the process were determined. 1. Introduction There has been an increasing concern in recent years about the possible adverse effects on human health of the emerging contaminants occurring in the aquatic environment. They are present even in effluents from wastewater treatment plants (WWTPs) at trace levels (from μg.L -1 to ng.L -1 ), including pharmaceuticals, personal care products, pesticides, surfactants, flame retardants, etc. The lack of validated analytical methods, nonuniform monitoring data, and the lack of accurate information about the fate and effects of these compounds and/or their metabolites and transformation byproducts in the aquatic environment make risk assessment problematic. So, the full extent and consequences of the presence of these compounds in the environment are therefore, still largely unknown [1]. These compounds occur in wastewater treatment plants effluents because they are truly persistent under the conditions of a conventional activated sludge process or because their microbial degradation was not fast enough to be completed within a low retention time. It is also accepted that some of these substances are beginning to be associated with adverse effects in aquatic organisms at environmentally relevant concentrations [1]. One of these mentioned micropollutants are pesticides, which are widely used not only in agriculture but also in domestic and industrial activities. This fact resulted in the presence of residues of these products and their metabolites in the environment [2]. Some of the most commercially important herbicides belong to the urea family, containing over 20 related compounds, as chlorotoluron, diuron or isoproturon. Isoproturon is water-soluble, moderately hydrophobic, and weakly adsorbed by soils. It has been reported concentrations in ground and surface water exceeding the limit levels [3]. European Union has approved different policies, such as Water Framework Directive 2000/60/EC, where the Directive 2013/39/EU includes a list of 45 priority compounds to be controlled, being one of them the isoproturon [4]. Adsorption technology is widely popular due to its simplicity, no requirements of chemical reactants, and the availability of a wide range of adsorbents. Therefore, it has been proved as the most promising option for the removal of the non-biodegradable organic compounds from aqueous streams. Activated carbon is the most common used adsorbent due to its effectiveness, versatility, and high adsorption capacity, which it is mainly conditioned by its porous structure and surface functional groups [5-6]. Research studies about micropollutants treatment by adsorption in fixed-bed column are scarce. From our knowledge, this is one of the first work about the elimination of isoproturon by activated carbon