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This study aims to evaluate the effect of the pyrolytic temperature on the biochar derived from the macauba endocarp for the removal of uranium (VI) from aqueous solutions. The endocarp was subjected to six different pyrolytic temperatures, ranging from 250 ºC to 750 ºC. The biochars obtained at each temperature were evaluated for their adsorption capacities ("q"). The highest adsorption capacities were obtained for the biochar produced at 250 ºC (BC250), followed by the one obtained at 350 ºC (BC350), with removal efficiencies of 86 % and 80 %, respectively. The best condition was achieved when the endocarp was subjected to temperatures between 300 and 350 °C, at which it was possible to obtain a satisfactory balance among adsorption capacity, gravimetric yield and fixed carbon content. This characteristic, combined with the high removal efficiency, points to an ideal working temperature of 350 °C. Elemental analysis showed a decrease of the H/C and O/C ratios when higher pyrolytic temperatures were applied, indicating an inverse relationship between the carbonization and the surface polar functional groups, which were likely responsible for an increased adsorptive capacity in biochars produced at lower temperatures. Both FTIR and XPS analysis indicated that oxygen-containing groups such as hydroxyls and carboxylic acids were involved with the binding of uranyl ions.

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The pharmaceutical compounds were analyzed in 14 sampling sites and pointed out the pollution sources related to raw sewage input and urban drainage discharge. Five medicine compounds, one illicit drug, and its metabolite were the higher measured content using analytical improvements tailored to identify and quantify organic compounds in low water content. The use of SPE cartridges followed by liquid chromatography with tandem mass spectrometry (LC-ESI-MS/MS) points out the Guavirutuba tributary as the primary water pollution source with higher concentrations in 2011 for pharmaceuticals, cocaine, and benzoylecgonine (metabolite) in the range of 6.7 ± 0.9 ng L −1 to 27.386 ± 142 ng L −1. The Jaceguay stream also located in Guarapiranga was the most preserved area and provided analytical values correspondent which lowered contamination content. Such concentrations mean a possible and feasible water restoration target. The most common compounds (above 90% samples) were: caffeine, atenolol, carbamazepine, cocaine, and benzoylecgonine. The integrated risk index for aquatic chemical pollution (IRICAP) confirms the higher contamination near Guavirutuba stream and the lower near the Jaceguay stream. Published results of cocaine and benzoylecgonine content in Guarapiranga basin corroborated with the analytical results.