wander botero | UFAL - Universidade Federal de Alagoas (original) (raw)

Papers by wander botero

Quimica Nova, 2009

The work reported here involved the characterization of sludges produced at water treatment plant... more The work reported here involved the characterization of sludges produced at water treatment plants in Jaboticabal-SP using FeCl3 as flocculant, and in Taquaritinga-SP and Manaus-AM using Al2(SO4)3 as flocculant. An evaluation was also made of the interaction of organic matter extracted from the sludges with different metal species. The results indicated that all the sludges produced at water treatment plants have an important agricultural potential and that their use depends on the characteristics of the raw water and the type of flocculant employed in conventional treatment. The humic substances extracted from the sludges showed different affinities for metal species, favoring eventual exchanges between potentially toxic metals and macro- and micronutrients. An alternative for the use of sludge in agriculture is to pretreat it to remove potentially toxic metals and enrich it with micro- and macronutrients that can be released to the plant.

CHARACTERIZATION OF SLUDGE GENERATED IN WATER TREATMENT PLANTS: PROSPECTS FOR AGRICULTURAL APPLIC... more CHARACTERIZATION OF SLUDGE GENERATED IN WATER TREATMENT PLANTS: PROSPECTS FOR AGRICULTURAL APPLICATION. The work reported here involved the characterization of sludges produced at water treatment plants in Jaboticabal-SP using ...

The sorption of four endocrine disruptors, bisphenol A (BPA), estrone (E1), 17β-estradiol (E2), a... more The sorption of four endocrine disruptors, bisphenol A (BPA), estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) in tropical sediment samples was studied in batch mode under different conditions of pH, time, and sediment amount. Data obtained from sorption experiments using the endocrine disruptors (EDs) and sediments containing different amounts of organic matter showed that there was a greater interaction between the EDs and organic matter (OM) present in the sediment, particularly at lower pH values. The pseudosecond order kinetics model successfully explained the interaction between the EDs and the sediment samples. The theoretical and experimentally obtained q e values were similar, and k values were smaller for higher SOM contents. The k F values, obtained from the Freundlich isotherms, varied in the ranges 4.2-7.4×10 −2 (higher OM sediment sample, S 2 ) and 1.7×10 −3 -3.1×10 −2 (lower OM sediment sample, S 1 ), the latter case indicating an interaction with the sediment that increased in the order: EE2>>E2>E1>BPA. These results demonstrate that the availability of endocrine disruptors may be directly related to the presence of organic material in sediment samples. Studies of this kind provide an important means of understanding the mobility, transport, and/or reactivity of this type of emergent contaminant in aquatic systems.

Improved agricultural productivity, and reduction of environmental impacts, require studies of th... more Improved agricultural productivity, and reduction of environmental impacts, require studies of the interactions between different soil components. Fertilizers marketed as "organic" or "natural", such as peats or humic substances (HS) extracted from peats, are enriched with macro and micronutrients that, according to the manufacturers, are released to the plant in accordance with its needs. This work investigates the complexation capacity of HS for macro and micronutrient metal species, considering the competition, for HS complexation sites, between non-essential metals (aluminium and lead), present in the soil, and the nutrients. Humic substances were found to possess strong affinities for Pb(II) and Al(III), forming stable complexes, with concomitant release of complexed nutrients. Although HS are already used commercially as organic fertilizers, further studies of methods of HS enrichment, aimed at avoiding losses, are highly desirable from environmental and economic perspectives.

This paper characterizes humic substances (HS) extracted from soil samples collected in the Rio N... more This paper characterizes humic substances (HS) extracted from soil samples collected in the Rio Negro basin in the state of Amazonas, Brazil, particularly investigating their reduction capabilities towards Hg(II) in order to elucidate potential mercury cycling/volatilization in this environment. For this reason, a multimethod approach was used, consisting of both instrumental methods (elemental analysis, EPR, solid-state NMR, FIA combined with cold-vapor AAS of Hg(0)) and statistical methods such as principal component analysis (PCA) and a central composite factorial planning method. The HS under study were divided into groups, complexing and reducing ones, owing to different distribution of their functionalities. The main functionalities (cor)related with reduction of Hg(II) were phenolic, carboxylic and amide groups, while the groups related with complexation of Hg(II) were ethers, hydroxyls, aldehydes and ketones. The HS extracted from floodable regions of the Rio Negro basin presented a greater capacity to retain (to complex, to adsorb physically and/or chemically) Hg(II), while nonfloodable regions showed a greater capacity to reduce Hg(II), indicating that HS extracted from different types of regions contribute in different ways to the biogeochemical mercury cycle in the basin of the mid-Rio Negro, AM, Brazil.

Química Nova, 2007

Page 1. Quim. Nova, Vol. 30, No. 2, 274-280, 2007 Artigo Dedicated to the Dr. Peter Burba recentl... more Page 1. Quim. Nova, Vol. 30, No. 2, 274-280, 2007 Artigo Dedicated to the Dr. Peter Burba recently retired from ISAS - Dortmund - Germany *e-mail: jrocha@iq.unesp. br DISTRIBUIÇÃO DE MERCÚRIO EM DIFERENTES SOLOS ...

JOURNAL-BRAZILIAN …, 2007

J. Braz. Chem. Soc., Vol. 18, No. 4, 824-830, 2007. Printed in Brazil - ©2007 Sociedade Brasileir... more J. Braz. Chem. Soc., Vol. 18, No. 4, 824-830, 2007. Printed in Brazil - ©2007 Sociedade Brasileira de Química 0103 - 5053 $6.00+0.00 ... Interaction between Humic Substances and Metallic Ions: a Selectivity Study of Humic Substances and their Possible Therapeutic Application

Quimica Nova, 2010

Given the variation observed in mercury in fish from natural lakes, it is difficult to determine ... more Given the variation observed in mercury in fish from natural lakes, it is difficult to determine what represents a background mercury level. Mercury in aquatic sediments is a potential source of this trace metal to biota, notably fish. Site specific factors, such as acidity and dissolved organic carbon have been shown to affect the mobilization of mercury and methylation of mercury. Methyl mercury is the most toxic form of this metal and the form most readily accumulated by biota. Thirtyfour headwater lakes, selected for a range in pH, were sampled for sediment mercury levels as part of an investigation of the impacts of acid rain on insular Newfoundland lakes. Selected physical and chemical data were also collected on all of the study sites. Acidity was not found to be significantly related to sediment mercury concentrations despite the wide range in pH. Pearson correlation analysis indicated that sediment mercury level was positively correlated with WA:LA (watershed to lake area ratio). WA:LA was also correlated with Secchi depth and colour. Linear regression was used to estimate the parameters of a model relating sediment mercury to WA:LA. Watershed area to lake area ratio was more important than site specific factors in governing the concentration of sediment mercury in lakes without industrial input.

Quimica Nova, 2009

The work reported here involved the characterization of sludges produced at water treatment plant... more The work reported here involved the characterization of sludges produced at water treatment plants in Jaboticabal-SP using FeCl3 as flocculant, and in Taquaritinga-SP and Manaus-AM using Al2(SO4)3 as flocculant. An evaluation was also made of the interaction of organic matter extracted from the sludges with different metal species. The results indicated that all the sludges produced at water treatment plants have an important agricultural potential and that their use depends on the characteristics of the raw water and the type of flocculant employed in conventional treatment. The humic substances extracted from the sludges showed different affinities for metal species, favoring eventual exchanges between potentially toxic metals and macro- and micronutrients. An alternative for the use of sludge in agriculture is to pretreat it to remove potentially toxic metals and enrich it with micro- and macronutrients that can be released to the plant.

CHARACTERIZATION OF SLUDGE GENERATED IN WATER TREATMENT PLANTS: PROSPECTS FOR AGRICULTURAL APPLIC... more CHARACTERIZATION OF SLUDGE GENERATED IN WATER TREATMENT PLANTS: PROSPECTS FOR AGRICULTURAL APPLICATION. The work reported here involved the characterization of sludges produced at water treatment plants in Jaboticabal-SP using ...

The sorption of four endocrine disruptors, bisphenol A (BPA), estrone (E1), 17β-estradiol (E2), a... more The sorption of four endocrine disruptors, bisphenol A (BPA), estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) in tropical sediment samples was studied in batch mode under different conditions of pH, time, and sediment amount. Data obtained from sorption experiments using the endocrine disruptors (EDs) and sediments containing different amounts of organic matter showed that there was a greater interaction between the EDs and organic matter (OM) present in the sediment, particularly at lower pH values. The pseudosecond order kinetics model successfully explained the interaction between the EDs and the sediment samples. The theoretical and experimentally obtained q e values were similar, and k values were smaller for higher SOM contents. The k F values, obtained from the Freundlich isotherms, varied in the ranges 4.2-7.4×10 −2 (higher OM sediment sample, S 2 ) and 1.7×10 −3 -3.1×10 −2 (lower OM sediment sample, S 1 ), the latter case indicating an interaction with the sediment that increased in the order: EE2>>E2>E1>BPA. These results demonstrate that the availability of endocrine disruptors may be directly related to the presence of organic material in sediment samples. Studies of this kind provide an important means of understanding the mobility, transport, and/or reactivity of this type of emergent contaminant in aquatic systems.

Improved agricultural productivity, and reduction of environmental impacts, require studies of th... more Improved agricultural productivity, and reduction of environmental impacts, require studies of the interactions between different soil components. Fertilizers marketed as "organic" or "natural", such as peats or humic substances (HS) extracted from peats, are enriched with macro and micronutrients that, according to the manufacturers, are released to the plant in accordance with its needs. This work investigates the complexation capacity of HS for macro and micronutrient metal species, considering the competition, for HS complexation sites, between non-essential metals (aluminium and lead), present in the soil, and the nutrients. Humic substances were found to possess strong affinities for Pb(II) and Al(III), forming stable complexes, with concomitant release of complexed nutrients. Although HS are already used commercially as organic fertilizers, further studies of methods of HS enrichment, aimed at avoiding losses, are highly desirable from environmental and economic perspectives.

This paper characterizes humic substances (HS) extracted from soil samples collected in the Rio N... more This paper characterizes humic substances (HS) extracted from soil samples collected in the Rio Negro basin in the state of Amazonas, Brazil, particularly investigating their reduction capabilities towards Hg(II) in order to elucidate potential mercury cycling/volatilization in this environment. For this reason, a multimethod approach was used, consisting of both instrumental methods (elemental analysis, EPR, solid-state NMR, FIA combined with cold-vapor AAS of Hg(0)) and statistical methods such as principal component analysis (PCA) and a central composite factorial planning method. The HS under study were divided into groups, complexing and reducing ones, owing to different distribution of their functionalities. The main functionalities (cor)related with reduction of Hg(II) were phenolic, carboxylic and amide groups, while the groups related with complexation of Hg(II) were ethers, hydroxyls, aldehydes and ketones. The HS extracted from floodable regions of the Rio Negro basin presented a greater capacity to retain (to complex, to adsorb physically and/or chemically) Hg(II), while nonfloodable regions showed a greater capacity to reduce Hg(II), indicating that HS extracted from different types of regions contribute in different ways to the biogeochemical mercury cycle in the basin of the mid-Rio Negro, AM, Brazil.

Química Nova, 2007

Page 1. Quim. Nova, Vol. 30, No. 2, 274-280, 2007 Artigo Dedicated to the Dr. Peter Burba recentl... more Page 1. Quim. Nova, Vol. 30, No. 2, 274-280, 2007 Artigo Dedicated to the Dr. Peter Burba recently retired from ISAS - Dortmund - Germany *e-mail: jrocha@iq.unesp. br DISTRIBUIÇÃO DE MERCÚRIO EM DIFERENTES SOLOS ...

JOURNAL-BRAZILIAN …, 2007

J. Braz. Chem. Soc., Vol. 18, No. 4, 824-830, 2007. Printed in Brazil - ©2007 Sociedade Brasileir... more J. Braz. Chem. Soc., Vol. 18, No. 4, 824-830, 2007. Printed in Brazil - ©2007 Sociedade Brasileira de Química 0103 - 5053 $6.00+0.00 ... Interaction between Humic Substances and Metallic Ions: a Selectivity Study of Humic Substances and their Possible Therapeutic Application

Quimica Nova, 2010

Given the variation observed in mercury in fish from natural lakes, it is difficult to determine ... more Given the variation observed in mercury in fish from natural lakes, it is difficult to determine what represents a background mercury level. Mercury in aquatic sediments is a potential source of this trace metal to biota, notably fish. Site specific factors, such as acidity and dissolved organic carbon have been shown to affect the mobilization of mercury and methylation of mercury. Methyl mercury is the most toxic form of this metal and the form most readily accumulated by biota. Thirtyfour headwater lakes, selected for a range in pH, were sampled for sediment mercury levels as part of an investigation of the impacts of acid rain on insular Newfoundland lakes. Selected physical and chemical data were also collected on all of the study sites. Acidity was not found to be significantly related to sediment mercury concentrations despite the wide range in pH. Pearson correlation analysis indicated that sediment mercury level was positively correlated with WA:LA (watershed to lake area ratio). WA:LA was also correlated with Secchi depth and colour. Linear regression was used to estimate the parameters of a model relating sediment mercury to WA:LA. Watershed area to lake area ratio was more important than site specific factors in governing the concentration of sediment mercury in lakes without industrial input.