ResuMo a região do Médio são Francisco representa um amplo espaço territorial, com marcante sazonalidade climática, diversidade de rochas, paisagens, solos, e, consequentemente, formações vegetais. No entanto, as relações entre as características edáficas e suas formações vegetais são pouco esclarecidas. Este estudo apresenta uma relação dos atributos edáficos, determinante para o estabelecimento de savana-estépica, savana-estépica florestada, savana, floresta estacional semidecidual e floresta estacional decidual nessa região, com base na análise de 166 perfis de solos. Em geral, os solos sob savana foram mais lixiviados e arenosos, álicos e restrito aos topos das paisagens; e os sob savana-estépica foram eutróficos, porém sódicos ou solódicos, e rasos, sempre associados às partes mais baixa da paisagem. A floresta estacional semidecidual apresentou forte variação dos atributos edáficos, indicando que sua ocorrência se baseia, principalmente, na disponibilidade de água. Houve grande semelhança entre os solos de savana-estépica florestada e floresta estacional decidual, sendo todos geralmente eutróficos, alcalinos e bem desenvolvidos, e suas diferenças restritas ao aspecto fisionômico da vegetação. Os domínios fitogeográficos do semiárido apresentaram-se pedologicamente bem diferenciados, sendo as savanas (cerrados) e savana-estépica (caatingas) similares às suas respectivas áreas nucleares. Além disso, as florestas estacionais deciduais evidenciaram atributos edáficos bem contrastantes com os domínios vizinhos, destacando essas formações como uma entidade fitogeográfica distinta. Palavras-chave: fitogeografia, geobotânica, relação solo-vegetação, semiárido brasileiro.Recebido para publicação em 31 de julho de 2015 e aprovado em 8 de setembro de 2015.
Marie Curie, Letter to her brother (1894) "Humanity stands... before a great problem of finding new raw materials and new sources of energy that shall never become exhausted. In the meantime, we must not waste what we have, but must leave as much as possible for coming generations." Svante Arrhenius, Chemistry in Modern Life (1925) v ACKNOWLEDGMENTS First, I would like to thank all my family for the support and for believing in my potential. Thanks Angelina Maria Lanna de Moraes and Fernando Machado Borges de Morais for bringing me to this existence and for educating me. Thanks, Rafael Lanna, for your unconditional brother support. Thanks to all my uncles Aurea, Zé Carlos, Iris, Rosana, Agrício (in memoriam), Léo and Daniel for all financial and emotional support. Special thanks to my life-partner Roberta Ferreira Monteiro for always being at my side, for believing in my mission and for your daily support. Thanks to my mother-in-law Rosália Ferreira Monteiro and my fatherin-law Maj. Idemar Monteiro (in memoriam) for everything. Thanks also to my brother-in-law Maj. Roberto Monteiro and all his family. I would like to acknowledge Prof a. Ana Claudia Queiroz Ladeira for the opportunity of studying at the CDTN under your supervision, for the trust in my work and for your important collaboration to the research. Thank you very much Prof a. Ascensión Murciego and Prof a. Esther Álvarez-Ayuso for the opportunity of studying at Salamanca under your supervision, for our partnership, for the unconditional help and for the unforgettable life experience. ¡Muchísimas gracias, Vale! Thanks to all my professors that shared their knowledge with me, contributing directly and indirectly to this thesis. Special thanks to Prof. Francisco Javier Rios (CDTN) and Clemente Recio (USAL) for creating the opportunity of double doctorate between the two institutions. Special thanks to Mr. Julius Martins for your high-quality proofreading. I would like to thank Indústrias Nucleares do Brasil (INB) for the partnership, the Comissão Nacional de Energia Nuclear (CNEN) for the scholarship, and CNPq, FINEP, Fapemig and Inct-Acqua for funding the research. I am also thankful to the Centro Nacional de Microscopía Electrónica-CNME (Madrid-Spain) for the TEM analysis, the Faculty of Chemistry of the Universidad Complutense de Madrid for the RMN analysis. I would like to thank the CDTN-Applied Physics Laboratory for the XPS analysis, especially to Prof. Pedro Lanna Gastelois and the CDTN Microscopy Laboratory for the and SEM analysis, especially to Dr. Tércio Assunção Pedrosa. Special thanks to Prof. José Domingos Ardisson (CDTN) for the 57 Fe Mössbauer spectroscopy analysis. Special thanks to the technicians and undergraduate internship students of all institutions, whose hard work and dedication were essential. Thanks to the undergraduate students Mariana Fadul, Ana Flávia Marinho Saraiva, Thales Augusto Carneiro and Augusto Alves Camargos for your unmeasurable contribution at the laboratory. Thanks to all my colleagues, especially Dr a. Elaine Fel...
Rare Earth Elements (REE) are one of the most strategical resources and have become the main interest of many developing and developed nations in the past seventy years, and its importance tend to increase further. New technologies demand these elements and some of them are critical, with high demand and limited supplies, amongst them are Y, Nd, Eu, Dy and Tb [1], [2]. In the state of Minas Gerais (Brazil), the mining industry plays a crucial role in the economy, whose main products are notably lead, zinc, gold, niobium, and copper. Furthermore, Minas Gerais has strategically important Rare Earth Element (REE) ores, whereas production is still incipient [3]. Acid Mine Drainage (AMD) is a continuous natural leaching process that may contain variable concentrations of REE, it occurs in some sites around the world [4]-[6]. One of these sites is located in a closed uranium mine in Caldas, Minas Gerais, Brazil, where the REE concentrations in AMD are about 130 mg L-1 [7], [8]. The AMD waters are treated with lime with a maximum flow rate of 300 m 3 h-1 , and the neutralization of the waters consumes about 12 t of lime per day and generates enormous amounts of precipitate [9]. The recovery of the RRE can yield in approximately 936 kg daily. Our research team is studying two ways of recovering the REE present in the AMD waters, using ionic resins and co-precipitation with iron, aluminum and manganese oxihydroxides. Results show that REE can be successfully recovered by both methods with high efficiency. Specifically, the use of a cationic resin in batch experiments can recover up to 90% of the REE present in the feed solution at pH = 1.3. The co-precipitation with aluminum and manganese oxihydroxides at pH = 8 can recover up to 95% of the REE present in a laboratory AMD, producing a solid phase with ±14% of REE oxides. Further studies focus on optimizing the processes and on concentrating the REE after the recovery, specifically the elution of the resins and the leaching of the precipitates.
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