A5014461582- Analytical chemistry methods development
- Minerals Flotation and Separation Techniques
- Geochemistry and Geologic Mapping
- Geochemistry and Elemental Analysis
- Catalytic Processes in Materials Science
- Mercury impact and mitigation studies
- Clay minerals and soil interactions
- Catalysis and Oxidation Reactions
- Fish biology, ecology, and behavior
- Analytical Chemistry and Chromatography
- Mineral Processing and Grinding
- Extraction and Separation Processes
- Water Quality Monitoring and Analysis
- Iron oxide chemistry and applications
- Metal Extraction and Bioleaching
- Geography and Environmental Studies
- Paleontology and Stratigraphy of Fossils
- Heavy metals in environment
- Catalysis and Hydrodesulfurization Studies
- Electrochemical Analysis and Applications
- Catalysts for Methane Reforming
- Laser-induced spectroscopy and plasma
- Chromium effects and bioremediation
- Advanced Chemical Sensor Technologies
- Geological and Geochemical Analysis
Centro de Tecnologia Mineral
2011-2023
University of Rio Grande and Rio Grande Community College
2018
Centro Tecnológico del Mueble y la Madera de la Región de Murcia
2002
Universidade Federal do Rio de Janeiro
1998
Universidade de São Paulo
1993
Instituto de Geociencias
1992-1993
Abstract This paper presents a comparative study of three decomposition methods (A, B and C) for the determination total Hg (THg) in crude oil related products by cold vapor atomic absorption spectrometry (CV-AAS). Methods A employed closed-pressurized (HPA-S) cold-finger systems, respectively. Method C pyrolysis system. Some procedures were introduced to improve weighing samples quartz boats, as well cleaning after sample pyrolysis. Also, their transfer into vessels, which too long heavy,...
A simple, fast and sensitive spectrophotometric method for the simultaneous determination of Cr(III) Cr(VI) in effluents contaminated waters using a UV-visible spectrophotometer, which operates with an advanced software multicomponent analysis, is proposed. The consists complexation Cr (III) EDTA reaction diphenylcarbazide (DPC). Variables, such as pH colour stability time, were studied. effect concomitant ions on was also investigated. sums chromium species concentrations obtained by...
A new method was developed for the determination of ammonium ion, monomethylamine and monoethylamine in saline waters by ion chromatography. Steam distillation used to eliminate matrix interferences. Variables such as time, concentration sodium hydroxide solution analyte mass were optimized using a full two-level factorial (23) design. The influence steam on analytical curves prepared different matrices also investigated. Limits detection 0.03, 0.05 mg/L obtained ammoniumion, monoethylamine,...
Tanned leather shavings from Brazilian tanneries were analysed in order to assess the chromium extractability and bioavailability, consequently its potential release into other environmental compartments when are deposited on landfill sites. The conventional SM&T (Standard, Measurement Testing Programme) sequential extractions scheme was applied. Also, Cr(VI) Cr(III) concentrations oxidizable fraction determined. results indicated high total (1.04, 1.46 2.74%) samples A, B C, respectively. A...
Rare earth elements (REEs) are very important to technological development as well geochemical and environmental studies. In this work, hydrofluoric acid (HF) was replaced by condensed phosphoric (CPA) in the digestion of geological samples, quantification REEs performed inductively coupled plasma‐optical emission spectrometry (ICP‐OES). Six international reference materials (RMs), named DC86318, CGL 111, 124, 126, OKA‐2 COQ‐1 three Brazilian ore Araxá, Catalão Pitinga were analysed. Only...
Abstract Chemical analysts use analytical blanks in their analyses, but seldom is this source of uncertainty evaluated. Generally, there great confusion. Although the numerical value blank, some situations, can be negligible, its cannot be. This article discusses contribution blank using a example copper content waters by flame atomic absorption spectrometry. The results indicate that uncertainties contribute up to 50% when sample considered analysis, confirming high impact. effect primarily...
Mn, Zn, Fe, Cd, Pb and Hg were determined in Zn-C alkaline batteries manufactured along almost 20 years. After samples disassembly the electroactive components treated with aqua regia bath ice for 24 h. Metals analyzed by ICP-OES. Zn Mn amounts did not vary significantly. Fe amount decreased, specially after 2000. Hg, Cd dramatically decreased time, being virtually absent 2005. still remains samples. Scanning electron microscopy of 1997 1998 showed presence Bi, In Cr plastic/paper...
SIMULATION OF NATUAL WEATHERING ZINC-CARBON AND ALKALINE BATTERIES.Spent alkaline and Zn-C batteries were placed in seawater, rainwater or landfill leachate at room temperature for up 30 days order to simulate natural weathering.After the experiments pH electrical conductivity of liquid measured.The precipitate formed filtrate submitted metal analysis by ICP-OES.Seawater is most corrosive medium, followed leachate.Pb, Cd Hg mainly filtrate.Fe, Mn Zn generally dominant precipitate.Na K...
Liquid-liquid equilibrium (LLE) data for the system biodiesel of chicken fat + methanol glycerol was measured at 25 and 45 °C atmospheric pressure. The zone miscibility found by means binodal curve, using density turbidity in each point its construction. Tie lines were defined through calibration curves glycerin phases. distribution selectivity coefficients determined. validation proved Othmer-Tobias Hand correlations, with close to unity. LLE correlated UNIQUAC model temperatures °C, global...