Bio-Geotechnologies for Mine Site Rehabilitation, 2018
Abstract Brazil is the lead supplier of uranium for South America, with the Uraniferous Province ... more Abstract Brazil is the lead supplier of uranium for South America, with the Uraniferous Province of Lagoa Real, located in southwestern Bahia state, being the most important monomineral province of the country. The process of mining uranium generates a huge quantity of a wide variety of waste residues composed of rocks containing uranium and other radionuclides. This waste is a potential source of contamination of the environment, and proper disposal and treatment of it is essential for environmental safety. This chapter will present the different techniques applied over the course of 14 years to the rehabilitation of a uranium mine in a semiarid climate with semiarid thorny scrub vegetation (Caatinga biome) in Brazil. The main rehabilitation strategies employed were the use of engineered blankets composed of plant fibers, the prospection of native grass species adapted to long periods of drought, and the use of legume species.
Journal of Liquid Chromatography & Related Technologies, 2015
Counter-current chromatography (CCC) was applied to the preparative separation of the methylxanti... more Counter-current chromatography (CCC) was applied to the preparative separation of the methylxantines (theophylline, theobromine, and caffeine) from the methanol extract of Theobroma cacao seeds. The solvent system used was composed of hexane-ethyl acetate–methanol–water (2:3:1:1 v/v/v/v) and the extraction was monitored by high-performance liquid chromatography employing conditions for a rapid determination of the methylxantines. The mixture of methylxantines obtained were analyzed using Microsorb-MV 100-5, 3 µm (C18) column (250 mm × 4, 6 mm), and mobile phase water:methanol (75:25) in the isocratic mode at a flow-rate of 5 mL/min and detection was carried out at 275 nm.
Bio-Geotechnologies for Mine Site Rehabilitation, 2018
Abstract Brazil is the lead supplier of uranium for South America, with the Uraniferous Province ... more Abstract Brazil is the lead supplier of uranium for South America, with the Uraniferous Province of Lagoa Real, located in southwestern Bahia state, being the most important monomineral province of the country. The process of mining uranium generates a huge quantity of a wide variety of waste residues composed of rocks containing uranium and other radionuclides. This waste is a potential source of contamination of the environment, and proper disposal and treatment of it is essential for environmental safety. This chapter will present the different techniques applied over the course of 14 years to the rehabilitation of a uranium mine in a semiarid climate with semiarid thorny scrub vegetation (Caatinga biome) in Brazil. The main rehabilitation strategies employed were the use of engineered blankets composed of plant fibers, the prospection of native grass species adapted to long periods of drought, and the use of legume species.
Journal of Liquid Chromatography & Related Technologies, 2015
Counter-current chromatography (CCC) was applied to the preparative separation of the methylxanti... more Counter-current chromatography (CCC) was applied to the preparative separation of the methylxantines (theophylline, theobromine, and caffeine) from the methanol extract of Theobroma cacao seeds. The solvent system used was composed of hexane-ethyl acetate–methanol–water (2:3:1:1 v/v/v/v) and the extraction was monitored by high-performance liquid chromatography employing conditions for a rapid determination of the methylxantines. The mixture of methylxantines obtained were analyzed using Microsorb-MV 100-5, 3 µm (C18) column (250 mm × 4, 6 mm), and mobile phase water:methanol (75:25) in the isocratic mode at a flow-rate of 5 mL/min and detection was carried out at 275 nm.
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Papers by Hector Hugo Silva Medrado