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Papers by Marco Alcântara

Atomic Absorption Spectroscopy, 2012

Nickel, although essential to plants, may be toxic to plants and animals. It is mainly assimilate... more Nickel, although essential to plants, may be toxic to plants and animals. It is mainly assimilated by food ingestion. However, information about the average levels of elements (including Ni) in edible vegetables from different regions is still scarce in Brazil. The objectives of this study were to: (a) evaluate and optimize a method for preparation of vegetable tissue samples for Ni determination; (b) optimize the analytical procedures for determination by Flame Atomic Absorption Spectrometry (FAAS) and by Electrothermal Atomic Absorption (ETAAS) in vegetable samples and (c) determine the Ni concentration in vegetables consumed in the cities of Lorena and Taubaté in the Vale do Paraíba, State of São Paulo, Brazil. By means of the analytical technique for determination by ETAAS or FAAS, the results were validated by the test of analyte addition and recovery. The most viable method tested for quantification of this element was HClO 4-HNO 3 wet digestion. All samples but carrot tissue collected in Lorena contained Ni levels above the permitted by the Brazilian Ministry of Health. The most disturbing results, requiring more detailed studies, were the Ni concentrations measured in carrot samples from Taubaté, where levels were five times higher than permitted by Brazilian regulations.

Revista Brasileira de …, 2001

... de Abreu ea Renata Presto, do Centro de Solos e Recursos Agroambientais do Instituto Agronômi... more ... de Abreu ea Renata Presto, do Centro de Solos e Recursos Agroambientais do Instituto Agronômico de Campinas - IAC/CSRA, pela colaboração em várias etapas deste trabalho, em especial nas determinações de crômio. LITERATURA CITADA Alcântara, MAK Eluviação de ...

International Review of Chemical Engineering (IRECHE), 2013

ABSTRACT The efficiency of a system composed with photochemical reactor based on Advanced Oxidati... more ABSTRACT The efficiency of a system composed with photochemical reactor based on Advanced Oxidation Process (AOP) followed by treatment in bioreactor was investigated as an alternative for treatment of dairy effluent in order to reduce the organic load. The influence of organic load in crude dairy effluent and pre-treated dairy wastewater were also investigated upon efficiency of biodegradation system based on Aerated Pond System (APS). The AOP was conducted using titanium dioxide (TiO2) as photocatalyst and solar irradiation. The catalytic bed was prepared by using TiO2, coating evenly with polyurethane, and fixing on a flat metal plate. Effluent was percolated and fixed at 23º angle of the North on a catalytic plate where it was irradiated for a three-hour period. The biodegradation tests were conducted during 72 hours. Chemical Oxygen Demand and Total Organic Carbon were employed to evaluate the total organic carbon reduction, respectively. Biodegradation of crude dairy effluent with an approximate COD value of 3,800 mg O2 L-1 presented around 26.01 ± 5.23% of carbon reduction. The AOP – APS system, which showed higher efficiency of organic load degradation, presented 93.70 ± 0.10% of total carbon reduction, characterized by a COD of entry into 3782.5 ± 37.6 mg O2 L-1 and a COD for the treated effluent output at 236.8 ± 0.1 mg O2 L-1. This data demonstrated the necessity of dairy wastewater pretreatment and the efficiency of pretreatment system based on TiO2/UVsolar

International Journal of Food Science and Nutrition Engineering, 2012

This investigation focused on the validation o f the methodology used in determining the presence... more This investigation focused on the validation o f the methodology used in determining the presence of specific elements in human blood. Concentrations of macro-and micronutrients in umbilical b lood (UCB) samples fro m 37 lactating volunteers who gave birth in the city of Taubaté , State of Sã o Paulo, Brazil. The determinations of Ca and Mg were carried out in a flame ato mic absorption spectrometer (FAAS) and those of Cr and Mn in a graphite furnace ato mic absorption spectrometer (GFAAS). A procedure for preparing samples was optimized and evaluated. Standard addition methods and determinations by ICP OES were used to validate the analytical procedures. An acetylene/air mixture was optimized at 2.0/17.0 L min-1 (Ca and Mg). Pyrolysis and atomizat ion temperatures for Cr were at 1400°C and 2100°C, respectively, for Mn at 1300°C and 1700°C, respectively. The most efficient chemical modifier was a solution containing 5 g of Pd + 3  g of Mg(NO3)2. Characteristic masses for Cr and Mn were 2.6 and 2.7 pg, respectively. The methods presented high analytical efficiency in the determination of Ca, Cr, Mg and Mn (recovery fro m 98.68% to 108.22 %). M inimal data variations in repeatability and reproducibility indicated significient precision and accuracy for the proposed methodology. The placenta did not block transport of elements fro m mother to fetus. The contents of the elements analyzed in the UCB were co mpared to those detected in maternal blood (M B). Most of the children exh ibited normal weight (fro m 2.5 to 3.0 kg) as per the Brazilian Min istry of Health standards. Such results indicate that the levels of concentrations of the elements in the UCB did not affect the weights of the neonates.

Water, Air, & Soil Pollution

… of radioanalytical and …, 2007

... Water, air and food are the different sources of trace elements to human body ... study, elem... more ... Water, air and food are the different sources of trace elements to human body ... study, elemental concentrations in different raw foodstuffs consumed in Libya were determined using INAA. ... using a planetary mill, Pulverisette5 with containers and grinding made of agate to minimize ...

… of radioanalytical and …, 2007

... Water, air and food are the different sources of trace elements to human body ... study, elem... more ... Water, air and food are the different sources of trace elements to human body ... study, elemental concentrations in different raw foodstuffs consumed in Libya were determined using INAA. ... using a planetary mill, Pulverisette5 with containers and grinding made of agate to minimize ...

Industrial & Engineering Chemistry Research

Environmental Engineering Science, 2016

This text is a brief review on the use of Advanced Oxidative Degradation Processes (AOPs) applied... more This text is a brief review on the use of Advanced Oxidative Degradation Processes (AOPs) applied to the treatment of sewage and industrial and domestic wastewaters. A quick introduction to the importance of wastewater treatment to the environment is discussed, followed by the benefits and limitations of treatment techniques. Chemical fundamentals are focused on the generation of hydroxyl radicals, hydrogen atom abstraction, electrophilic addition of hydroxyl radicals, electrical transfer, and radical-radical reactions. AOPs are herein divided into two categories: homogeneous and heterogeneous. Homogeneous methods are based on the use of radical generators like hydrogen peroxide, ozone, the combined use of these oxidants, Fenton's reagent and photo-Fenton. Heterogeneous systems focus on the use of semiconductors, and results concerning the use of semiconductors in AOPs are discussed at the end.

Pesquisa Agropecuaria Brasileira, Feb 1, 2010

Aguas Subterrâneas, Jan 27, 2012

Revista Brasileira de Ciência do Solo

Journal of the Brazilian Chemical Society, 2015

This work describes the treatment of dairy industry effluent using catalytic ozonation with Fe 2+... more This work describes the treatment of dairy industry effluent using catalytic ozonation with Fe 2+ as its catalyst in a semi-batch process with recycle. A fractional factorial design 2 4-1 was used with a reduction percentage of total organic carbon (TOCred) as response. Optimal conditions were obtained by the reaction time of 30 min, ozonator power of 35 W, O 2 flow rate of 0.125 L min-1 , Fe 2+ concentration of 1.0 g L-1 and pH 4.0 for a 2 L raw effluent. TOCred of 64.03% represents a decrease in concentration from 473.0 to 170.1 mg L-1 , with an estimate cost of US$ 0.03 L-1 effluent. The treatment performed was not sufficient to discharge it directly on surface water; however, significant reduction of TOCred, among physical and chemical characteristics makes a better product to be proceeded into a biological treatment.

Atomic Absorption Spectroscopy, 2012

Nickel, although essential to plants, may be toxic to plants and animals. It is mainly assimilate... more Nickel, although essential to plants, may be toxic to plants and animals. It is mainly assimilated by food ingestion. However, information about the average levels of elements (including Ni) in edible vegetables from different regions is still scarce in Brazil. The objectives of this study were to: (a) evaluate and optimize a method for preparation of vegetable tissue samples for Ni determination; (b) optimize the analytical procedures for determination by Flame Atomic Absorption Spectrometry (FAAS) and by Electrothermal Atomic Absorption (ETAAS) in vegetable samples and (c) determine the Ni concentration in vegetables consumed in the cities of Lorena and Taubaté in the Vale do Paraíba, State of São Paulo, Brazil. By means of the analytical technique for determination by ETAAS or FAAS, the results were validated by the test of analyte addition and recovery. The most viable method tested for quantification of this element was HClO 4-HNO 3 wet digestion. All samples but carrot tissue collected in Lorena contained Ni levels above the permitted by the Brazilian Ministry of Health. The most disturbing results, requiring more detailed studies, were the Ni concentrations measured in carrot samples from Taubaté, where levels were five times higher than permitted by Brazilian regulations.

Revista Brasileira de …, 2001

... de Abreu ea Renata Presto, do Centro de Solos e Recursos Agroambientais do Instituto Agronômi... more ... de Abreu ea Renata Presto, do Centro de Solos e Recursos Agroambientais do Instituto Agronômico de Campinas - IAC/CSRA, pela colaboração em várias etapas deste trabalho, em especial nas determinações de crômio. LITERATURA CITADA Alcântara, MAK Eluviação de ...

International Review of Chemical Engineering (IRECHE), 2013

ABSTRACT The efficiency of a system composed with photochemical reactor based on Advanced Oxidati... more ABSTRACT The efficiency of a system composed with photochemical reactor based on Advanced Oxidation Process (AOP) followed by treatment in bioreactor was investigated as an alternative for treatment of dairy effluent in order to reduce the organic load. The influence of organic load in crude dairy effluent and pre-treated dairy wastewater were also investigated upon efficiency of biodegradation system based on Aerated Pond System (APS). The AOP was conducted using titanium dioxide (TiO2) as photocatalyst and solar irradiation. The catalytic bed was prepared by using TiO2, coating evenly with polyurethane, and fixing on a flat metal plate. Effluent was percolated and fixed at 23º angle of the North on a catalytic plate where it was irradiated for a three-hour period. The biodegradation tests were conducted during 72 hours. Chemical Oxygen Demand and Total Organic Carbon were employed to evaluate the total organic carbon reduction, respectively. Biodegradation of crude dairy effluent with an approximate COD value of 3,800 mg O2 L-1 presented around 26.01 ± 5.23% of carbon reduction. The AOP – APS system, which showed higher efficiency of organic load degradation, presented 93.70 ± 0.10% of total carbon reduction, characterized by a COD of entry into 3782.5 ± 37.6 mg O2 L-1 and a COD for the treated effluent output at 236.8 ± 0.1 mg O2 L-1. This data demonstrated the necessity of dairy wastewater pretreatment and the efficiency of pretreatment system based on TiO2/UVsolar

International Journal of Food Science and Nutrition Engineering, 2012

This investigation focused on the validation o f the methodology used in determining the presence... more This investigation focused on the validation o f the methodology used in determining the presence of specific elements in human blood. Concentrations of macro-and micronutrients in umbilical b lood (UCB) samples fro m 37 lactating volunteers who gave birth in the city of Taubaté , State of Sã o Paulo, Brazil. The determinations of Ca and Mg were carried out in a flame ato mic absorption spectrometer (FAAS) and those of Cr and Mn in a graphite furnace ato mic absorption spectrometer (GFAAS). A procedure for preparing samples was optimized and evaluated. Standard addition methods and determinations by ICP OES were used to validate the analytical procedures. An acetylene/air mixture was optimized at 2.0/17.0 L min-1 (Ca and Mg). Pyrolysis and atomizat ion temperatures for Cr were at 1400°C and 2100°C, respectively, for Mn at 1300°C and 1700°C, respectively. The most efficient chemical modifier was a solution containing 5 g of Pd + 3  g of Mg(NO3)2. Characteristic masses for Cr and Mn were 2.6 and 2.7 pg, respectively. The methods presented high analytical efficiency in the determination of Ca, Cr, Mg and Mn (recovery fro m 98.68% to 108.22 %). M inimal data variations in repeatability and reproducibility indicated significient precision and accuracy for the proposed methodology. The placenta did not block transport of elements fro m mother to fetus. The contents of the elements analyzed in the UCB were co mpared to those detected in maternal blood (M B). Most of the children exh ibited normal weight (fro m 2.5 to 3.0 kg) as per the Brazilian Min istry of Health standards. Such results indicate that the levels of concentrations of the elements in the UCB did not affect the weights of the neonates.

Water, Air, & Soil Pollution

… of radioanalytical and …, 2007

... Water, air and food are the different sources of trace elements to human body ... study, elem... more ... Water, air and food are the different sources of trace elements to human body ... study, elemental concentrations in different raw foodstuffs consumed in Libya were determined using INAA. ... using a planetary mill, Pulverisette5 with containers and grinding made of agate to minimize ...

… of radioanalytical and …, 2007

... Water, air and food are the different sources of trace elements to human body ... study, elem... more ... Water, air and food are the different sources of trace elements to human body ... study, elemental concentrations in different raw foodstuffs consumed in Libya were determined using INAA. ... using a planetary mill, Pulverisette5 with containers and grinding made of agate to minimize ...

Industrial & Engineering Chemistry Research

Environmental Engineering Science, 2016

This text is a brief review on the use of Advanced Oxidative Degradation Processes (AOPs) applied... more This text is a brief review on the use of Advanced Oxidative Degradation Processes (AOPs) applied to the treatment of sewage and industrial and domestic wastewaters. A quick introduction to the importance of wastewater treatment to the environment is discussed, followed by the benefits and limitations of treatment techniques. Chemical fundamentals are focused on the generation of hydroxyl radicals, hydrogen atom abstraction, electrophilic addition of hydroxyl radicals, electrical transfer, and radical-radical reactions. AOPs are herein divided into two categories: homogeneous and heterogeneous. Homogeneous methods are based on the use of radical generators like hydrogen peroxide, ozone, the combined use of these oxidants, Fenton's reagent and photo-Fenton. Heterogeneous systems focus on the use of semiconductors, and results concerning the use of semiconductors in AOPs are discussed at the end.

Pesquisa Agropecuaria Brasileira, Feb 1, 2010

Aguas Subterrâneas, Jan 27, 2012

Revista Brasileira de Ciência do Solo

Journal of the Brazilian Chemical Society, 2015

This work describes the treatment of dairy industry effluent using catalytic ozonation with Fe 2+... more This work describes the treatment of dairy industry effluent using catalytic ozonation with Fe 2+ as its catalyst in a semi-batch process with recycle. A fractional factorial design 2 4-1 was used with a reduction percentage of total organic carbon (TOCred) as response. Optimal conditions were obtained by the reaction time of 30 min, ozonator power of 35 W, O 2 flow rate of 0.125 L min-1 , Fe 2+ concentration of 1.0 g L-1 and pH 4.0 for a 2 L raw effluent. TOCred of 64.03% represents a decrease in concentration from 473.0 to 170.1 mg L-1 , with an estimate cost of US$ 0.03 L-1 effluent. The treatment performed was not sufficient to discharge it directly on surface water; however, significant reduction of TOCred, among physical and chemical characteristics makes a better product to be proceeded into a biological treatment.