Maurício Fontes - Profile on Academia.edu (original) (raw)
Papers by Maurício Fontes
Development of cedro-rosa seedlings in soil contaminated by copper: tolerance and the potential for soil phytostabilization proposal
... Sandro Marcelo de Caires I ; Maurício Paulo Ferreira Fontes II ; Raphael Bragança Alves Ferna... more ... Sandro Marcelo de Caires I ; Maurício Paulo Ferreira Fontes II ; Raphael Bragança Alves Fernandes II ; Júlio César Lima Neves II Renildes Lúcio Ferreira Fontes II. ... [ Links ]. VERVAEKE, P. et al. Phytoremediation prospects of willow stands on contaminated sediment: a field trial. ...
Mobility of heavy metals as related to soil chemical and mineralogical characteristics of Brazilian soils
Environmental …, 2001
In order to better understand the relationship between soil characteristics and mobility of some ... more In order to better understand the relationship between soil characteristics and mobility of some heavy metals, correlation studies were conducted in samples of unlimed and limed A, B and C horizons of three Brazilian soils, representative of the majority of the tropical soils. A number of chemical and mineralogical characteristics of one Oxisol and two Ultisols were related to the retardation factors (Rf) for zinc (Zn), cadmium (Cd), copper (Cu) and lead (Pb). The retardation factors, obtained in leaching column experiments, were used as an estimate of solute movement in the profile. Soil types and soil horizons were found to influence metal retardation factors which, in turn, correlated better with the chemical than the mineralogical soil characteristics. For the unlimed soil samples, the soil characteristics that significantly correlated with Zn-Rf and Cd-Rf were the sum of exchangeable bases (SB), and soil exchangeable (Ca-KCl) and non-exchangeable (Ca-HCl) calcium contents. These results showed the strong influence of the cation exchange phenomenon on the retention and mobility of these two metals. For Cu and Pb, not only SB, cation exchange capacity (CEC) and Ca-KCl and Ca-HCl but also the organic matter correlated well with the Rf, showing that complex or chelate formation may play an important role in the movement of these elements. The important soil chemical characteristics related to the retardation factors in the limed soil samples were SB for Cd, and Ca-HCl for Cu and Pb, suggesting that precipitation may also influence the mobility and retention of the latter two heavy metals in these soil samples. Soil pH influenced the heavy metals adsorption and movement as shown by the significant correlation with the retardation factors when the combined data for the unlimed and limed soil samples was considered.
The Cu, Ni and Zn accumulations in leaves and roots of lettuce (Lactuca sativa L) grown in soil a... more The Cu, Ni and Zn accumulations in leaves and roots of lettuce (Lactuca sativa L) grown in soil amended with natural and contaminated cattle manure vermicompost were evaluated. The vermicompost residues containing relatively high metal concentrations used in this work were obtained from a previous experiment, in which vermicompost was applied to removing metals from electroplating wastes. Sequential lettuce cultivations were conducted in pots containing the residual substrates from the first cultivation by adding metal-enriched vermicompost residues. In general, the Cu, Ni and Zn concentrations in leaves and roots of lettuce plants grown in vermicompost enriched with these metals were higher than in the treatment using the natural vermicompost. The metal concentrations in leaves from treatments with natural vermicompost were below the critical concentrations of toxicity to plants. However, the metal concentrations in leaves of the third cultivation in which metal-enriched vermicompost was applied were greater than the upper limit that causes plant toxicity, but no visual damage was observed in the plants. Treatment with Zn-enriched vermicompost resulted in toxicity symptoms, but plant damage did not result in the death of the plant. The chemical fractionation of Cu, Ni and Zn in residues from lettuce cultivation was evaluated by using a sequential extraction procedure and metal concentrations were increased in the different chemical fractions according to the increase of vermicompost dose.
Lead speciation and availability affected by plants in a contaminated soil
Chemosphere
Química Nova
The gold and iron mining activities in the Velhas River yield considerable amounts of suspended s... more The gold and iron mining activities in the Velhas River yield considerable amounts of suspended solids as well as metals to the hydrological system of the region. Thus, the present study sought to evaluate the concentrations of arsenic and trace metals in the waters and their distribution and mobility in sediment by BCR sequential extraction. Arsenic concentrations in the water samples were between 78.1 and 85.3 μg L -1 , which exceeded 10 μg L -1 (maximum limit permitted by Brazilian environmental regulations for water destined to human consumption, CONAMA Resolution 357/2005). The sequential extraction of the sediment showed considerable amounts of As (20%), Cd (55%), Co (56%), Cr (16%), Cu (23%), Ni (29%), Pb (47%) and Zn (71%) associated with the geochemical fractions considered potentially available for the remobilization to the aquatic environment. The presence of the elements in these fractions indicated high ecotoxicological risk and potential harm to the health of the local population.
Química Nova
On November 5, 2015, the Fundão dam ruptured which caused the spill of a large quantity of tailin... more On November 5, 2015, the Fundão dam ruptured which caused the spill of a large quantity of tailings from the extraction of iron ores to the Gualaxo do Norte, Carmo and Doce Rivers. Seven months prior to the rupture, our group had collected water and sediment samples at 13 points along the Tripuí Creek and the entire length of the Carmo River. Six months after deposition of the mud, new samples were collected in the Carmo River. Thus, the present study sought to evaluate the concentrations of trace elements in the waters and their distribution and mobility in sediment by BCR sequential extraction before and after the deposition of the tailings mud. Arsenic concentrations in the water samples were between 10.4 and 50.4 µg L -1 , which exceeded 10 ug L -1 (maximum limit permitted by Brazilian environmental regulations for water destined for human consumption) . The tailing mud layer on the sediments caused concentration increases of As (20%), Cd (13%), Co (5%), Cr (9%), Cu (11%), Ni (4%), Pb (7%) and Zn (19%) in the easily remobilized fractions. The presence of the elements in these fractions was indicative of high ecotoxicological risk and potential harm to the health of the local population.
Speciation, bioaccessibility and potential risk of chromium in Amazon forest soils
Environmental pollution (Barking, Essex : 1987), Jan 16, 2018
Even though the Amazon region is widely studied, there is still a gap regarding Cr exposure and i... more Even though the Amazon region is widely studied, there is still a gap regarding Cr exposure and its risk to human health. The objectives of this study were to 1) determine Cr concentrations in seven chemical fractions and 6 particle sizes in Amazon soils, 2) quantify hexavalent Cr (CrVI) concentrations using an alkaline extraction, 3) determine the oral and lung bioaccessible Cr, and 4) assess Cr exposure risks based on total and bioaccessible Cr in soils. The total Cr in both A (0-20 cm) and B (80-100 cm) horizons was high at 2346 and 1864 mg kg. However, sequential extraction indicated that available Cr fraction was low compared to total Cr, with Cr in the residual fraction being the highest (74-76%). There was little difference in total Cr concentrations among particle sizes. Hexavalent Cr concentration was also low, averaging 0.72 and 2.05 mg kg in A and B horizon. In addition, both gastrointestinal (21-22 mg kg) and lung (0.95-1.25 mg kg) bioaccessible Cr were low (<1.2%). T...
Reserva mineral e caracterização mineralógica de solos do Rio Grande do Sul
Revista Brasileira de Ciência Avícola
Behavior of Heavy Metals in Soils
Competitive Sorption and Transport of Heavy Metals in Soils and Geological Media, 2012
Formas de potássio e magnésio em solos do Rio Grande do Sul, e sua relação com o conteúdo na planta e com a produção em plantios de eucalipto
Revista Brasileira de Ciência do Solo
Revista Brasileira de Ciência do Solo, 2002
As propriedades químicas e cristalográficas detalhadas da caulinita (Ct) e dos óxidos de ferro do... more As propriedades químicas e cristalográficas detalhadas da caulinita (Ct) e dos óxidos de ferro do solo e dos sedimentos do Grupo Barreiras são pouco conhecidas. Para estudar as características desses minerais em profundidade, coletaram-se 11 amostras (0,7; 1,4; 2,1; 2,8; 3,5; 4,2; 4,9; 5,6; 7,7; 10,5 e 14m) nos horizontes Bt, BC e C de um Argissolo Amarelo no município de Aracruz (ES). As frações argila e silte foram estudadas por difração de raios-X (DRX), análise termo-diferencial (ATD) e microscopia eletrônica. Os teores totais de Fe e outros microelementos (Cr, Mn, Ni, Pb, Ti e Zn) da fração argila foram determinados por espectrometria por emissão por plasma, após digestão da amostra com HF concentrado. Nos extratos resultantes das extrações com oxalato de amônio (OA) e ditionito-citrato-bicarbonato (DCB), determinaram-se os teores de Fe, Al, Si, Cr, Mn, Ni, Pb, Ti e Zn. A composição química da Ct das frações argila (amostra desferrificada) e silte (amostra natural) foi determin...
Revista Brasileira de Ciência do Solo, 2001
Este trabalho objetivou avaliar a utilização da água quente e CaCl2 5 mmol L-1 como extratores de... more Este trabalho objetivou avaliar a utilização da água quente e CaCl2 5 mmol L-1 como extratores de B disponível, usando forno de microondas como fonte de aquecimento, e estudar a influência de algumas características do solo nos teores de B extraído. A dosagem de B nos extratos foi feita com azometina-H. Executou-se um experimento em casa de vegetação em fatorial completo 17 solos x 6 doses de B (0, 0,15, 0,30, 0,60, 0,90 e 1,50 mg dm-3), com três repetições, em blocos ao acaso, usando o milho como planta-teste. Os solos foram analisados por meio dos dois extratores e os teores de B e a produção de matéria seca da parte aérea foram medidos. Foram feitas análises de regressão e correlação para as diversas variáveis, trabalhando com os dados de todas as doses ou apenas com a dose zero. Verificou-se que os extratores revelaram capacidades semelhantes na determinação do B disponível; o CaCl2 5 mmol L-1 recuperou 8% a mais do B aplicado, em relação à água quente; a elevação dos teores de ...
Pesquisa Agropecuária Tropical, 2011
Preparation and evaluation of hydrotalcite-iron oxide magnetic organocomposite intercalated with surfactants for cationic methylene blue dye removal
Chemical Engineering Journal, 2014
BioResources, 2013
The objective of this study was to assess the chemical properties of wood from six clones of Euca... more The objective of this study was to assess the chemical properties of wood from six clones of Eucalyptus spp. relative to charcoal yield and its properties, determine the correlations between the evaluated parameters and identify a clone of Eucalyptus having the greatest potential for charcoal to steelmaking use. The study of chemical properties included analysis of elemental composition, contents of cellulose, hemicelluloses, lignin, and ash, the syringyl/guaiacyl ratio (S/G), and the index of crystalline cellulose in the wood. The pyrolysis of wood was done in an electric laboratory oven. The gravimetric yield in charcoal, the content of volatile matter, fixed carbon and ash, higher heating value, and elementary composition were determined. Data were subjected to an analysis of variance, and after the difference between them was established, the Tukey test was applied. The Pearson correlation was employed as well. The results indicated that the contents of carbon, oxygen, and hydrogen in the wood significantly affected the charcoal yields and its higher heating value. Higher rates of crystalline cellulose favored the gravimetric yield in charcoal. The S/G ratio contributed more to the charcoal yield when compared to total lignin content.
The Scientific World Journal, 2012
The environmental quality of the Jacuípe River's estuary (very important in northeastern Braz... more The environmental quality of the Jacuípe River's estuary (very important in northeastern Brazil) was assessed during 2007 and 2008. In water, concentrations (mg L−1) ofNO2-(<0.004 to 0.016),NO3-(0.01 to 0.33), solublePO43-(<0.02 to 0.22), dissolved oxygen (3.9 to 9.6), total contents (mg L−1) of Cd (<0.001), Cu (<0.01), Pb (<0.01), and Zn (<0.1), pH (5.60 to 8.00), and electrical conductivity (0.12 to 48.60 mS cm−1) agreed with environmental standards. In sediments, clay and total organic matter (%, m/m) varied, respectively, from 8.8 to 12.0 and from 1.1 to 8.8, while infrared, thermogravimetric profile, electronic micrograph, as well as X-Ray analyses showed desirable adsorptive characteristics. However, maximum exchangeable levels (mg kg−1) of Cd (1.3), Cu (44.6), Pb (35.7), and Zn (43.7) and their respective maximum pseudototal concentrations (mg kg−1): 19.4, 95.1, 68.2, and 30.3 were below the recommended limits. In this sense, it was possible to demonstra...
Carbono Orgánico Extraído Por Soluciones Salinas y Su Relación Con Otras Formas De Carbono De Suelos Tropicales Organic Carbon Extracted by Saline Solutions and Its Relation to Other Soil Carbon Forms in Tropical Soils
La materia orgánica de suelos tropicales se separó en diferentes fracciones de acuerdo con aspect... more La materia orgánica de suelos tropicales se separó en diferentes fracciones de acuerdo con aspectos fisicoquímicos directamente ligados a la dinámica de nutrimentos en el suelo. Para ello, se de- sarrolló una metodología para la extracción de carbono orgánico (Corg) ligado a los sitios de intercambio de suelos tropicales, selec- cionando los mejores extractores, cuantificando el C org extraído (Cext)
Water, Air, & Soil Pollution, 2013
Although Cd concentrations in uncontaminated soils are usually low, pollution of soils by Cd from... more Although Cd concentrations in uncontaminated soils are usually low, pollution of soils by Cd from different sources of contamination pose problems. The application of soil amendments to increase plant production has been used as a viable alternative for recovery of soils contaminated with Cd. However, emphasis needs to be placed on the nature of Cd sorption processes in order that the amendments can be managed appropriately. A range of materials including vermicompost, sugarcane filter cake, palm kernel pie, lime, phosphate rock, and zeolite were used for the sorption studies. Total and nonspecific Cd sorption was estimated by batch experiments, and specific sorption was obtained by the difference between the former and the latter. Best adsorbents for specific Cd sorption from soil amendments were lime and zeolite. Langmuir adsorption isotherms fitted reasonably well in the experimental data, and their constants were evaluated, with R 2 values from 0.80 to 0.99. The maximum adsorption capacity of Cd(II) was higher for mineral amendments than for organic amendments and ranged from 0.89 to 10.86 gkg -1 . The small value (0.08 Lmg -1 ) of the constant related to the energy of adsorption indicated that Cd was bound weakly to the palm kernel pie. Thermodynamic parameter, the Gibbs free energy, was calculated for each system, and the negative values obtained confirm that the adsorption processes were spontaneous. The values of separation factor, R L , which has been used to predict affinity between adsorbate and adsorbent were between 0 and 1, indicating that sorption was very favorable for Cd(II).
International Journal of Environmental Studies, 2011
The potential of cattle manure vermicompost and Brazilian soils (whole soils and soils incubated ... more The potential of cattle manure vermicompost and Brazilian soils (whole soils and soils incubated with vermicompost) was assessed for adsorption of heavy metals such as Cu(II) and Cd(II) from aqueous solutions. Experimental data have been fitted to Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model, with R 2 values from 0.89 to 0.99. Based on the maximum adsorption capacity obtained from the Langmuir isotherm the affinity of the studied metals for the vermicompost and soils have been established as Cu(II) > Cd(II). The values of the separation factor, R L , which has been used to predict affinity between adsorbate and adsorbent were between zero and 1, indicating that sorption was very favourable for Cu(II) and Cd(II) in synthetic solution. Addition of vermicompost to soils resulted in higher distribution coefficient, K d , as compared with whole soils. The thermodynamic parameter, the Gibbs energy changes, was calculated for each system and the negative values obtained confirm that the adsorption processes are spontaneous. The DG°values for the substrates were between À2.630 ± 1.41 kJ mol À1 and À13.700 ± 1.250 kJ mol À1. Adsorption tests from multimetal systems confirm the affinity order obtained in the individual metal tests. The adsorption capacity for Cu(II) measured in individual tests is not reduced by the presence of Cd(II). There is also desorption of Cu(II) and Cd(II) previously bound to vermicompost, whole soils and soils incubated with vermicompost by DTPA. The experiment indicates the importance of cattle manure vermicompost and oxisol amended with vermicompost in relation to Cu(II) and Cd(II) adsorption from aqueous solution.
Plant Species for Revegetation of Overburden Rock and Iron Mine Spoil of the Alegria Iron Mine, Mariana, Minas Gerais State, …
Pesquisa Agropecuária …
Abstract:<!--@ page {margin: 2cm}-->< p class=" western" align=" justify&... more Abstract:<!--@ page {margin: 2cm}-->< p class=" western" align=" justify"> An experiment was conducted to verify the potentiality of some plant species to revegetate areas under the influence of iron mining. Field conditions were simulated laying mining overburden (soil, ...
Development of cedro-rosa seedlings in soil contaminated by copper: tolerance and the potential for soil phytostabilization proposal
... Sandro Marcelo de Caires I ; Maurício Paulo Ferreira Fontes II ; Raphael Bragança Alves Ferna... more ... Sandro Marcelo de Caires I ; Maurício Paulo Ferreira Fontes II ; Raphael Bragança Alves Fernandes II ; Júlio César Lima Neves II Renildes Lúcio Ferreira Fontes II. ... [ Links ]. VERVAEKE, P. et al. Phytoremediation prospects of willow stands on contaminated sediment: a field trial. ...
Mobility of heavy metals as related to soil chemical and mineralogical characteristics of Brazilian soils
Environmental …, 2001
In order to better understand the relationship between soil characteristics and mobility of some ... more In order to better understand the relationship between soil characteristics and mobility of some heavy metals, correlation studies were conducted in samples of unlimed and limed A, B and C horizons of three Brazilian soils, representative of the majority of the tropical soils. A number of chemical and mineralogical characteristics of one Oxisol and two Ultisols were related to the retardation factors (Rf) for zinc (Zn), cadmium (Cd), copper (Cu) and lead (Pb). The retardation factors, obtained in leaching column experiments, were used as an estimate of solute movement in the profile. Soil types and soil horizons were found to influence metal retardation factors which, in turn, correlated better with the chemical than the mineralogical soil characteristics. For the unlimed soil samples, the soil characteristics that significantly correlated with Zn-Rf and Cd-Rf were the sum of exchangeable bases (SB), and soil exchangeable (Ca-KCl) and non-exchangeable (Ca-HCl) calcium contents. These results showed the strong influence of the cation exchange phenomenon on the retention and mobility of these two metals. For Cu and Pb, not only SB, cation exchange capacity (CEC) and Ca-KCl and Ca-HCl but also the organic matter correlated well with the Rf, showing that complex or chelate formation may play an important role in the movement of these elements. The important soil chemical characteristics related to the retardation factors in the limed soil samples were SB for Cd, and Ca-HCl for Cu and Pb, suggesting that precipitation may also influence the mobility and retention of the latter two heavy metals in these soil samples. Soil pH influenced the heavy metals adsorption and movement as shown by the significant correlation with the retardation factors when the combined data for the unlimed and limed soil samples was considered.
The Cu, Ni and Zn accumulations in leaves and roots of lettuce (Lactuca sativa L) grown in soil a... more The Cu, Ni and Zn accumulations in leaves and roots of lettuce (Lactuca sativa L) grown in soil amended with natural and contaminated cattle manure vermicompost were evaluated. The vermicompost residues containing relatively high metal concentrations used in this work were obtained from a previous experiment, in which vermicompost was applied to removing metals from electroplating wastes. Sequential lettuce cultivations were conducted in pots containing the residual substrates from the first cultivation by adding metal-enriched vermicompost residues. In general, the Cu, Ni and Zn concentrations in leaves and roots of lettuce plants grown in vermicompost enriched with these metals were higher than in the treatment using the natural vermicompost. The metal concentrations in leaves from treatments with natural vermicompost were below the critical concentrations of toxicity to plants. However, the metal concentrations in leaves of the third cultivation in which metal-enriched vermicompost was applied were greater than the upper limit that causes plant toxicity, but no visual damage was observed in the plants. Treatment with Zn-enriched vermicompost resulted in toxicity symptoms, but plant damage did not result in the death of the plant. The chemical fractionation of Cu, Ni and Zn in residues from lettuce cultivation was evaluated by using a sequential extraction procedure and metal concentrations were increased in the different chemical fractions according to the increase of vermicompost dose.
Lead speciation and availability affected by plants in a contaminated soil
Chemosphere
Química Nova
The gold and iron mining activities in the Velhas River yield considerable amounts of suspended s... more The gold and iron mining activities in the Velhas River yield considerable amounts of suspended solids as well as metals to the hydrological system of the region. Thus, the present study sought to evaluate the concentrations of arsenic and trace metals in the waters and their distribution and mobility in sediment by BCR sequential extraction. Arsenic concentrations in the water samples were between 78.1 and 85.3 μg L -1 , which exceeded 10 μg L -1 (maximum limit permitted by Brazilian environmental regulations for water destined to human consumption, CONAMA Resolution 357/2005). The sequential extraction of the sediment showed considerable amounts of As (20%), Cd (55%), Co (56%), Cr (16%), Cu (23%), Ni (29%), Pb (47%) and Zn (71%) associated with the geochemical fractions considered potentially available for the remobilization to the aquatic environment. The presence of the elements in these fractions indicated high ecotoxicological risk and potential harm to the health of the local population.
Química Nova
On November 5, 2015, the Fundão dam ruptured which caused the spill of a large quantity of tailin... more On November 5, 2015, the Fundão dam ruptured which caused the spill of a large quantity of tailings from the extraction of iron ores to the Gualaxo do Norte, Carmo and Doce Rivers. Seven months prior to the rupture, our group had collected water and sediment samples at 13 points along the Tripuí Creek and the entire length of the Carmo River. Six months after deposition of the mud, new samples were collected in the Carmo River. Thus, the present study sought to evaluate the concentrations of trace elements in the waters and their distribution and mobility in sediment by BCR sequential extraction before and after the deposition of the tailings mud. Arsenic concentrations in the water samples were between 10.4 and 50.4 µg L -1 , which exceeded 10 ug L -1 (maximum limit permitted by Brazilian environmental regulations for water destined for human consumption) . The tailing mud layer on the sediments caused concentration increases of As (20%), Cd (13%), Co (5%), Cr (9%), Cu (11%), Ni (4%), Pb (7%) and Zn (19%) in the easily remobilized fractions. The presence of the elements in these fractions was indicative of high ecotoxicological risk and potential harm to the health of the local population.
Speciation, bioaccessibility and potential risk of chromium in Amazon forest soils
Environmental pollution (Barking, Essex : 1987), Jan 16, 2018
Even though the Amazon region is widely studied, there is still a gap regarding Cr exposure and i... more Even though the Amazon region is widely studied, there is still a gap regarding Cr exposure and its risk to human health. The objectives of this study were to 1) determine Cr concentrations in seven chemical fractions and 6 particle sizes in Amazon soils, 2) quantify hexavalent Cr (CrVI) concentrations using an alkaline extraction, 3) determine the oral and lung bioaccessible Cr, and 4) assess Cr exposure risks based on total and bioaccessible Cr in soils. The total Cr in both A (0-20 cm) and B (80-100 cm) horizons was high at 2346 and 1864 mg kg. However, sequential extraction indicated that available Cr fraction was low compared to total Cr, with Cr in the residual fraction being the highest (74-76%). There was little difference in total Cr concentrations among particle sizes. Hexavalent Cr concentration was also low, averaging 0.72 and 2.05 mg kg in A and B horizon. In addition, both gastrointestinal (21-22 mg kg) and lung (0.95-1.25 mg kg) bioaccessible Cr were low (<1.2%). T...
Reserva mineral e caracterização mineralógica de solos do Rio Grande do Sul
Revista Brasileira de Ciência Avícola
Behavior of Heavy Metals in Soils
Competitive Sorption and Transport of Heavy Metals in Soils and Geological Media, 2012
Formas de potássio e magnésio em solos do Rio Grande do Sul, e sua relação com o conteúdo na planta e com a produção em plantios de eucalipto
Revista Brasileira de Ciência do Solo
Revista Brasileira de Ciência do Solo, 2002
As propriedades químicas e cristalográficas detalhadas da caulinita (Ct) e dos óxidos de ferro do... more As propriedades químicas e cristalográficas detalhadas da caulinita (Ct) e dos óxidos de ferro do solo e dos sedimentos do Grupo Barreiras são pouco conhecidas. Para estudar as características desses minerais em profundidade, coletaram-se 11 amostras (0,7; 1,4; 2,1; 2,8; 3,5; 4,2; 4,9; 5,6; 7,7; 10,5 e 14m) nos horizontes Bt, BC e C de um Argissolo Amarelo no município de Aracruz (ES). As frações argila e silte foram estudadas por difração de raios-X (DRX), análise termo-diferencial (ATD) e microscopia eletrônica. Os teores totais de Fe e outros microelementos (Cr, Mn, Ni, Pb, Ti e Zn) da fração argila foram determinados por espectrometria por emissão por plasma, após digestão da amostra com HF concentrado. Nos extratos resultantes das extrações com oxalato de amônio (OA) e ditionito-citrato-bicarbonato (DCB), determinaram-se os teores de Fe, Al, Si, Cr, Mn, Ni, Pb, Ti e Zn. A composição química da Ct das frações argila (amostra desferrificada) e silte (amostra natural) foi determin...
Revista Brasileira de Ciência do Solo, 2001
Este trabalho objetivou avaliar a utilização da água quente e CaCl2 5 mmol L-1 como extratores de... more Este trabalho objetivou avaliar a utilização da água quente e CaCl2 5 mmol L-1 como extratores de B disponível, usando forno de microondas como fonte de aquecimento, e estudar a influência de algumas características do solo nos teores de B extraído. A dosagem de B nos extratos foi feita com azometina-H. Executou-se um experimento em casa de vegetação em fatorial completo 17 solos x 6 doses de B (0, 0,15, 0,30, 0,60, 0,90 e 1,50 mg dm-3), com três repetições, em blocos ao acaso, usando o milho como planta-teste. Os solos foram analisados por meio dos dois extratores e os teores de B e a produção de matéria seca da parte aérea foram medidos. Foram feitas análises de regressão e correlação para as diversas variáveis, trabalhando com os dados de todas as doses ou apenas com a dose zero. Verificou-se que os extratores revelaram capacidades semelhantes na determinação do B disponível; o CaCl2 5 mmol L-1 recuperou 8% a mais do B aplicado, em relação à água quente; a elevação dos teores de ...
Pesquisa Agropecuária Tropical, 2011
Preparation and evaluation of hydrotalcite-iron oxide magnetic organocomposite intercalated with surfactants for cationic methylene blue dye removal
Chemical Engineering Journal, 2014
BioResources, 2013
The objective of this study was to assess the chemical properties of wood from six clones of Euca... more The objective of this study was to assess the chemical properties of wood from six clones of Eucalyptus spp. relative to charcoal yield and its properties, determine the correlations between the evaluated parameters and identify a clone of Eucalyptus having the greatest potential for charcoal to steelmaking use. The study of chemical properties included analysis of elemental composition, contents of cellulose, hemicelluloses, lignin, and ash, the syringyl/guaiacyl ratio (S/G), and the index of crystalline cellulose in the wood. The pyrolysis of wood was done in an electric laboratory oven. The gravimetric yield in charcoal, the content of volatile matter, fixed carbon and ash, higher heating value, and elementary composition were determined. Data were subjected to an analysis of variance, and after the difference between them was established, the Tukey test was applied. The Pearson correlation was employed as well. The results indicated that the contents of carbon, oxygen, and hydrogen in the wood significantly affected the charcoal yields and its higher heating value. Higher rates of crystalline cellulose favored the gravimetric yield in charcoal. The S/G ratio contributed more to the charcoal yield when compared to total lignin content.
The Scientific World Journal, 2012
The environmental quality of the Jacuípe River's estuary (very important in northeastern Braz... more The environmental quality of the Jacuípe River's estuary (very important in northeastern Brazil) was assessed during 2007 and 2008. In water, concentrations (mg L−1) ofNO2-(<0.004 to 0.016),NO3-(0.01 to 0.33), solublePO43-(<0.02 to 0.22), dissolved oxygen (3.9 to 9.6), total contents (mg L−1) of Cd (<0.001), Cu (<0.01), Pb (<0.01), and Zn (<0.1), pH (5.60 to 8.00), and electrical conductivity (0.12 to 48.60 mS cm−1) agreed with environmental standards. In sediments, clay and total organic matter (%, m/m) varied, respectively, from 8.8 to 12.0 and from 1.1 to 8.8, while infrared, thermogravimetric profile, electronic micrograph, as well as X-Ray analyses showed desirable adsorptive characteristics. However, maximum exchangeable levels (mg kg−1) of Cd (1.3), Cu (44.6), Pb (35.7), and Zn (43.7) and their respective maximum pseudototal concentrations (mg kg−1): 19.4, 95.1, 68.2, and 30.3 were below the recommended limits. In this sense, it was possible to demonstra...
Carbono Orgánico Extraído Por Soluciones Salinas y Su Relación Con Otras Formas De Carbono De Suelos Tropicales Organic Carbon Extracted by Saline Solutions and Its Relation to Other Soil Carbon Forms in Tropical Soils
La materia orgánica de suelos tropicales se separó en diferentes fracciones de acuerdo con aspect... more La materia orgánica de suelos tropicales se separó en diferentes fracciones de acuerdo con aspectos fisicoquímicos directamente ligados a la dinámica de nutrimentos en el suelo. Para ello, se de- sarrolló una metodología para la extracción de carbono orgánico (Corg) ligado a los sitios de intercambio de suelos tropicales, selec- cionando los mejores extractores, cuantificando el C org extraído (Cext)
Water, Air, & Soil Pollution, 2013
Although Cd concentrations in uncontaminated soils are usually low, pollution of soils by Cd from... more Although Cd concentrations in uncontaminated soils are usually low, pollution of soils by Cd from different sources of contamination pose problems. The application of soil amendments to increase plant production has been used as a viable alternative for recovery of soils contaminated with Cd. However, emphasis needs to be placed on the nature of Cd sorption processes in order that the amendments can be managed appropriately. A range of materials including vermicompost, sugarcane filter cake, palm kernel pie, lime, phosphate rock, and zeolite were used for the sorption studies. Total and nonspecific Cd sorption was estimated by batch experiments, and specific sorption was obtained by the difference between the former and the latter. Best adsorbents for specific Cd sorption from soil amendments were lime and zeolite. Langmuir adsorption isotherms fitted reasonably well in the experimental data, and their constants were evaluated, with R 2 values from 0.80 to 0.99. The maximum adsorption capacity of Cd(II) was higher for mineral amendments than for organic amendments and ranged from 0.89 to 10.86 gkg -1 . The small value (0.08 Lmg -1 ) of the constant related to the energy of adsorption indicated that Cd was bound weakly to the palm kernel pie. Thermodynamic parameter, the Gibbs free energy, was calculated for each system, and the negative values obtained confirm that the adsorption processes were spontaneous. The values of separation factor, R L , which has been used to predict affinity between adsorbate and adsorbent were between 0 and 1, indicating that sorption was very favorable for Cd(II).
International Journal of Environmental Studies, 2011
The potential of cattle manure vermicompost and Brazilian soils (whole soils and soils incubated ... more The potential of cattle manure vermicompost and Brazilian soils (whole soils and soils incubated with vermicompost) was assessed for adsorption of heavy metals such as Cu(II) and Cd(II) from aqueous solutions. Experimental data have been fitted to Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model, with R 2 values from 0.89 to 0.99. Based on the maximum adsorption capacity obtained from the Langmuir isotherm the affinity of the studied metals for the vermicompost and soils have been established as Cu(II) > Cd(II). The values of the separation factor, R L , which has been used to predict affinity between adsorbate and adsorbent were between zero and 1, indicating that sorption was very favourable for Cu(II) and Cd(II) in synthetic solution. Addition of vermicompost to soils resulted in higher distribution coefficient, K d , as compared with whole soils. The thermodynamic parameter, the Gibbs energy changes, was calculated for each system and the negative values obtained confirm that the adsorption processes are spontaneous. The DG°values for the substrates were between À2.630 ± 1.41 kJ mol À1 and À13.700 ± 1.250 kJ mol À1. Adsorption tests from multimetal systems confirm the affinity order obtained in the individual metal tests. The adsorption capacity for Cu(II) measured in individual tests is not reduced by the presence of Cd(II). There is also desorption of Cu(II) and Cd(II) previously bound to vermicompost, whole soils and soils incubated with vermicompost by DTPA. The experiment indicates the importance of cattle manure vermicompost and oxisol amended with vermicompost in relation to Cu(II) and Cd(II) adsorption from aqueous solution.
Plant Species for Revegetation of Overburden Rock and Iron Mine Spoil of the Alegria Iron Mine, Mariana, Minas Gerais State, …
Pesquisa Agropecuária …
Abstract:<!--@ page {margin: 2cm}-->< p class=" western" align=" justify&... more Abstract:<!--@ page {margin: 2cm}-->< p class=" western" align=" justify"> An experiment was conducted to verify the potentiality of some plant species to revegetate areas under the influence of iron mining. Field conditions were simulated laying mining overburden (soil, ...