The initial concentration of the pollutant employed in this work (100 mg/L of nicotine) was higher than that found in the environmental [57] in order to measure ecotoxicity evolution of reaction mixture following the standard Microtox test procedure. Taking into account the maximum concentration of iron cation permitted for the discharge of industrial wastewater in the region of Madrid (Spain), 10 mg/L of Fe2+ was selected as the concentration when carrying out the Fenton runs. Employing higher concentrations of this iron source would require a further recovery or elimination step, which would be undesirable from an economical point of view. Lower catalyst amounts would slow down oxidation kinetics. All reactions were carried out in a batch manner at two different temperatures (20 and 50 °C). The initial pH was adjusted to a value of 3.5 by addition of sulfuric acid. The pH and oxidation–reduction potential were measured during the runs using pH and ORP electrodes, respectively, for a period of 120 min in order to ensure that the reaction was complete. Experimental conditions are summarized in Table 1. Liquid samples were withdrawn periodically and analyzed. Nicotine was quantified by HPLC (Hewlett-Packard, mod. 1100) using a Diode Array detector (HP G1315A) with a Chromolith Performance column (monolithic silica in rod form, RP-18e 1004.6 mm) as the stationary phase and a 92.5/7.5 (v/v) mixture of acetonitrile and water as the mobilephase.The flowrate of the mobile phase was 1 mLmin−1and a UV detector was use data wavelength of 210 nm