Navegando por Palavras-chave "Heavy metals"
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- ItemAcesso aberto (Open Access)Avaliação da exposição ao chumbo em trabalhadores de cooperativas de reciclagem da região metropolitana de São Paulo(Universidade Federal de São Paulo, 2013-11-29) Regina, Carlos Alberto Conde [UNIFESP]; Assunção, Nilson Antonio de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)In this study the availability and quantification of lead in recycling cooperatives and in nails of collectors of recyclable materials was performed in the metropolitan São Paulo, assessing the possible metal impacts on the behavioral health of the collectors due to their chronic contact with heavy metals during incorrect handling of electronic waste. Lead was analyzed in soils, in locals of public contact in cooperatives and in nails. The analyses were conducted using a Field Portable Spectrometer-Ray and the nails were analyzed in laboratory by Atomic Absorption Spectroscopy Graphite Furnace. A socio-behavioral questionnaire was applied to these workers to check if in some way, inside the socio-cultural scenario experienced by them, the presence of lead in these workplaces interfered in their everyday behavior. Concentrations of lead in situ were found at a range 10-10.437 ppm in routine places of such workers, and 11.170-240.872 ppm in electronic materials incorrectly stored in the field. In nails, lead concentrations were found to range from 0.12 to 15.8 mg/g. According to the methodology applied to evaluate the workers behavior, 40% of respondents had performance of anxiety and depression, 38% reported aggressive behaviors, 68% suffer from internalizing problems and 52% from externalizing problems.
- ItemAcesso aberto (Open Access)Estudo da caracterização de sílica do tipo SBA-15,funcionalizada: novo materiais para remediação de sistemas aquosos contaminados com metais potencialmente tóxicos, utilizando Pb2+ como poluente modelo(Universidade Federal de São Paulo, 2014-10-03) Silva, Fernanda Alves da [UNIFESP]; Mercuri, Lucildes Pita [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Heavy metals are among the most harmful aquatic contaminants. Therefore, there is a growing interest in obtaining materials adsorbents to capture these contaminants from effluent In this work the synthesis of mesoporous silica SBA-15 and its functionalization with aminopropyltrimethoxysilane (APTMS) , chitosan (QTS) and ethylenediaminetetraacetic acid (EDTA) were carried out in order to compare the functionalization of silicatic support with different organic agents and apply the new materials as adsorbents to uptake heavy metals from water. The functionalization of SBA-15 with APTMS was based on the post-synthesis grafting method, in toluene, and the EDTA and QTS incorporation were made by impregnation method, using dichloromethane and 2 % aqueous acetic acid as solvent, respectively. APTMS, EDTA, QTS, SBA-15 and new obtained materials (SBA-15/APTMS, SBA-15/QTS, SBA-15/EDTA, SBA-15/APTMS/QTS and SBA-15/APTMS/EDTA) were characterized by analytical and physical chemistry techniques: Thermogravimetry / Derivative Thermogravimetry (TG / DTG), Differential Scanning Calorimetry (DSC), Elemental Analysis (EA), Adsorption/Desorption of Nitrogen, Fourier Transformed Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Regarding functionalized samples, the functionalization of SBA-15 with APTMS there was effective and about 30% of agent was incorporated to silica, as all results showed. The incorporation of chitosan was effective in SBA-15 supported functionalized with APTMS and also to the pure support, presenting an increase of the thermal stability of the polymer impregnated to silica. Regarding the incorporation of EDTA, there was no experimental evidence that indicates incorporation of the agent to the substrate. Furthermore, it was found that stirring times had little influence on incorporation of the actives. The preliminary tests of sorption of Pb2+ in aqueous media showed SBA-15/APTMS and SBA-15/APTMS/QTS samples presented the best results, with sorption of 100.0% and 39.5% of the lead present in the solution, respectively. On the other hand, the sample of pure commercial quitosan retained 99.1% of Pb2+ ions in the solution after 30 minutes of contact.
- ItemSomente MetadadadosFrom micro to nanocrystalline boron doped diamond applied to cadmium detection(Elsevier Science Sa, 2017) Sardinha, Andre F.; Arantes, Tatiane M.; Cristovan, Fernando H. [UNIFESP]; Ferreira, Neidenei G.Cadmium detection was investigated by Square Wave Anodic Stripping Voltammetry (SWASV) measurements by using boron doped diamond electrodes with different morphologies from micro to nanocrocrystalline grains as Boron Doped Diamond (BDD) and Boron Doped Nanocrystalline Diamond (BDND), respectively. The argon concentrations, in the argon/hydrogen ratio, used were 0, 50, 60, 70, and 80 vol.%. SWASV technique was applied in 4 x 10(-4) mol L-1 ammonium acetate buffer pH 42. The peak currents were measured for Cd2+ concentration ranging from 1 to 20 mu g L-1. This change in film grain size and roughness affected how cadmium was deposited on the electrode surfaces, thus affecting its electroanalytical response from SWASV measurements as well as its selectivity. For all electrodes cadmium detection limits (DL) were lower than 1 mu g L-1 while for BDND electrode DL reached 0.016 mu g L-1. These values are lower than that required by the Brazilian Health Ministry for potable water (1 mu g L-1) and confirm that diamond electrodes are a suitable mercury-free method to determine cadmium trace levels in water. A strong correlation between the electrode selectivity and its grain size also confirmed the best performance of BDND electrode. (C) 2017 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosLead detection using micro/nanocrystalline boron-doped diamond by square-wave anodic stripping voltammetry(Elsevier B.V., 2014-10-01) Arantes, Tatiane M.; Sardinha, Andre [UNIFESP]; Baldan, Mauricio R.; Cristovan, Fernando H. [UNIFESP]; Ferreira, Neidenei G.; LAS INPE Natl Inst Space Res; Universidade Federal de São Paulo (UNIFESP)Monitoring heavy metal ion levels in water is essential for human health and safety. Electroanalytical techniques have presented important features to detect toxic trace heavy metals in the environment due to their high sensitivity associated with their easy operational procedures. Square-wave voltammetry is a powerful electrochemical technique that may be applied to both electrokinetic and analytical measurements, and the analysis of the characteristic parameters of this technique also enables the mechanism and kinetic evaluation of the electrochemical process under study. in this work, we present a complete optimized study on the heavy metal detection using diamond electrodes. It was analyzed the influence of the morphology characteristics as well as the doping level on micro/nanocrystalline boron-doped diamond films by means of square-wave anodic stripping voltammetry (SWASV) technique. the SWASV parameters were optimized for all films, considering that their kinetic response is dependent on the morphology and/or doping level. the films presented reversible results for the Lead [Pb (II)] system studied. the Pb (II) analysis was performed in ammonium acetate buffer at pH 4.5, varying the lead concentration in the range from 1 to 10 mu g L-1. the analytical responses were obtained for the four electrodes. However, the best low limit detection and reproducibility was found for boron doped nanocrystalline diamond electrodes (BDND) doped with 2000 mg L-1 in B/C ratio. (C) 2014 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosRapid bacteria identification from environmental mining samples using MALDI-TOF MS analysis(Springer Heidelberg, 2017) Avanzi, Ingrid Regina; Gracioso, Louise Hase; Baltazar, Marcela dos Passos Galluzzi; Karolski, Bruno; Perpetuo, Elen Aquino [UNIFESP]; Nascimento, Claudio Augusto Oller doCopper mining has polluted soils and water, causing a reduction of the microbial diversity and a change in the structure of the resident bacterial communities. In this work, selective isolation combined with MALDI-TOF MS and the 16S rDNA method were used for characterizing cultivable bacterial communities from copper mining samples. The results revealed that MALDI-TOF MS analysis can be considered a reliable and fast tool for identifying copper-resistant bacteria from environmental samples at the genera level. Even though some results were ambiguous, accuracy can be improved by enhancing reference databases. Therefore, mass spectra analysis provides a reliable method to facilitate monitoring of the microbiota from copper-polluted sites. The understanding of the microbial community diversity in coppercontaminated sites can be helpful to understand the impact of the metal on the microbiome and to design bioremediation processes.