R. Dallago - Academia.edu (original) (raw)

Papers by R. Dallago

Research paper thumbnail of Extração e recuperação de prata e mercúrio em efluentes gerados na determinação de DQO empregando métodos físico-químicos

Engenharia Sanitaria e Ambiental, 2008

Durante as análises de Demanda Química de Oxigênio (DQO) é gerado um efluente líquido que se cara... more Durante as análises de Demanda Química de Oxigênio (DQO) é gerado um efluente líquido que se caracteriza pela presença de elevadas concentrações de metais pesados (Hg, Ag, Cr e Fe). Visando à remoção seletiva destes metais, possibilitando suas reutilizações, foram avaliados diferentes agentes precipitantes (Cl-, Br-, I- e S= para a Ag e o Hg e NaOH, NH4OH e NaHCO3 para o Cr e o Fe). Para a Ag e o Hg os melhores resultados em termos de remoção e recuperação seletiva foram obtidos quando do emprego seqüencial dos íons cloreto e sulfeto. Devido à presença de Hg(I), se fez necessário o emprego de NH4OH para separar seletivamente a Ag, presente na forma de AgCl, precipitada concomitantemente com Hg(I) como Hg2Cl2. Para o Cr e o Fe foram obtidas remoções que satisfazem à legislação (FEPAM) para ambos os elementos, somente quando do emprego do NaOH como agente precipitante.

Research paper thumbnail of Study of the Relation between the Inorganic and Organic Material in the Air Pollution of the City of Caxias do Sul

The main objective of this work was the semi-quantitative evaluation of the influence of the conc... more The main objective of this work was the semi-quantitative evaluation of the influence of the concentrations of fine and coarse particulate matter (PM 2.5 and PM 10) and black carbon (BC) on the organic compound concentrations in the atmosphere of Caxias do Sul, a city in Rio Grande do Sul, the southernmost state of Brazil. The collection of the samples was carried out between August of 2006 and January of 2007. The periodic replacement of the cartridges and sampling filters was performed every other day (48 h sampling). An active sampler was used for the collection of the inorganic particulate matter, that means, PM 2.5 and PM 10 were sampled using stacked filter units that collect fine (d < 2.5 μm) and coarse (2.5 μm < d < 10 μm) particulate matter. The organic material was collected by a previously treated cotton cartridge. Both samplings (inorganic and organic matter) were performed at the same time and sampling point, with division of the air flux. The air was forced to pass through the two samplers by a vacuum pump. The inorganic particulate matter was characterized by gravimetry and reflectance. The tentative identification of the organic compounds was obtained by gas chromatography with mass spectrometry detection (GC-MS). The preliminary results suggest an inverse relation among the PM 10 concentration and the amounts of some organic compounds like 1H-indene, neridol and ethylphthalate. On the other hand, the maximum quantity of eburnamonine was detected at the same time as the maximum concentrations of BC. No correlations were found between the PM 2.5 concentrations and the amounts of organic compounds, in the samples studied.

Research paper thumbnail of Solid waste from tanneries as adsorbent for the removal of dyes in aqueous medium

Química Nova, 2005

... Technol. Biotechnol. 1991, 50, 257. [ Links ]. 26. McKay, G.; Allen, SJ; J. Sep. Process Tech... more ... Technol. Biotechnol. 1991, 50, 257. [ Links ]. 26. McKay, G.; Allen, SJ; J. Sep. Process Technol. 1983, 4, 1. [ Links ]. 27. Nicolet, L.; Rott, U.; Water Sci. ... 36. Hoinacki, E.; Gutheil, NC; Peles e Couros: origens, defeitos e industrialização, CIENTEC: Porto Alegre, 1978. [ Links ]. 37. ...

Research paper thumbnail of Preliminary Study of Some Plasticizers Compounds in Sewage Before and After the Treatment in a Sewage Treatment Plant

Chemical engineering transactions, 2008

Oliveira M., Dallago R.M., Dellanora R., and Nascimento I.F. Chemical Engineering Department, Uni... more Oliveira M., Dallago R.M., Dellanora R., and Nascimento I.F. Chemical Engineering Department, Universidade de Caxias do Sul, RS-Brazil Chemistry Department, URI – campus de Erechim, RS-Brazil Technological Center, URI – campus de Erechim, RS-Brazil Physics and Chemistry Department – Universidade de Caxias do Sul, Avenida Francisco Getúlio Vargas, 1130, CEP 95070-560, Caxias do Sul, RS-Brazil e-mail: inascimf@ucs.br

Research paper thumbnail of Eletrofloculação no tratamento de dejeto suíno submetido ao pré-tratamento de digestão anaeróbia

Research paper thumbnail of Desenvolvimento de catalisadores ambientais de Pd-W/gama-Al2O3 e Pd/Mo/gama-Al2O3

Research paper thumbnail of Decomposi��o catal�tica de �xidos de nitrog�nio

Research paper thumbnail of Adsorption of organic matter by inorganic particulate in air pollution

Air Pollution XVIII, 2010

Research paper thumbnail of Decomposição catalítica de óxidos de nitrogênio

Research paper thumbnail of Optimization of the methodology for lead extraction from waste contaminated with heavy metals

Environmental Technology, 2010

A sequential experimental design strategy is used to optimize the extraction of lead from slag. T... more A sequential experimental design strategy is used to optimize the extraction of lead from slag. The slag is composed mainly of iron (= 60%) and lead (= 6%), and cannot be disposed of in conventional landfill due to its high lead content. The extraction of lead is based on the complexing properties of ethylenediaminetetra-acetic acid (EDTA), the iron being masked with fluoride ions. Atomic absorption spectroscopy (AAS) has been used for monitoring iron and lead concentrations. In a first step, Plackett-Burman PB-12 experimental design was used for screening the variables and for selecting those to be used. Two central composite designs (CCDs) were then carried out to determine the optimal conditions for lead extraction. The optimized experimental conditions were established to be: contact time with the fluoride solution 30 min; particle size of slag between 150 and 600 microm; molecular concentration of fluoride solution 2.4 x 10(-3) mol and of EDTA 5 x 10(-4) mol; pH 1.5; 8 h contact time with the EDTA solution; and temperature 60 degrees C. Under these experimental conditions the lead content was reduced by 57% compared with the raw sample.

Research paper thumbnail of Enzymatic production of linalool esters in organic and solvent-free system

Bioprocess and Biosystems Engineering, 2009

This work investigated the influence of temperature, enzyme concentration, substrates molar ratio... more This work investigated the influence of temperature, enzyme concentration, substrates molar ratio, in the absence and presence of organic solvent, at two molar ratios of the substrates on the enzymatic production of linalil esters using the immobilized lipase Novozym 435 as catalyst, different acids and linalool and Ho-Sho essential oil as substrates. The best reaction conversion was obtained at the highest temperature (70 degrees C), for both solvent free (3.81%) and with solvent addition (2.25%), for a solvent to substrates molar ratio of 2:1, enzyme concentration of 5 wt% and acid to alcohol molar ratio of 1:1. The reaction kinetics revealed that Ho-Sho essential oil afforded the greatest conversions when compared with pure linalool. Higher linalil esters production were achieved after 10 h reaction (5.58%) in 2:1 solvent to substrates molar ratio, with enzyme concentration of 5 wt%, at 70 degrees C and anhydride to alcohol molar ratio of 1:1 using Ho-Sho essential oil as substrate.

Research paper thumbnail of Resíduos sólidos de curtumes como adsorventes para a remoção de corantes em meio aquoso

Química Nova, 2005

Recebido em 5/4/04; aceito em 9/9/04; publicado na web em 4/2/05 SOLID WASTE FROM TANNERIES AS AD... more Recebido em 5/4/04; aceito em 9/9/04; publicado na web em 4/2/05 SOLID WASTE FROM TANNERIES AS ADSORBENT FOR THE REMOVAL OF DYES IN AQUEOUS MEDIUM. The tanning process in the leather industry generates very high quantities of chromium-containing solid waste ("wet blue" leather). Environmental concerns and escalating landfill-costs are becoming increasingly serious problems for the leather industry and an alternative disposal is needed. In this work, we are presenting a novel application for this solid waste, which is the removal of organic contaminants from aqueous-solution. The adsorption isotherm of "wet blue" leather waste from the AUREA tanning company in Erechim-RS (Brazil) showed that this material presents high adsorption capacities of the reactive textile dyes.

Research paper thumbnail of AVALIAÇÃO DA ESTABILIDADE ENZIMÁTICA DO EXTRATO PECTINOLÍTICO DE Aspergillus niger ATCC 9642 IMOBILIZADO EM SUPORTE POLIMÉRICO-INORGÂNICO MINERALIZADO BIOMIMETICAMENTE

Anais do XX Congresso Brasileiro de Engenharia Química

Research paper thumbnail of EFEITO DA ESTABILIDADE DE ESTOCAGEM DA LIPASE COMERCIAL DE Candida antarctica B (CALB) NA FORMA LIVRE E IMOBILIZADA POR CONFINAMENTO EM SUPORTE DE POLIURETANO

Anais do XX Congresso Brasileiro de Engenharia Química, 2015

Research paper thumbnail of ESTUDO DA TERMORRESISTÊNCIA DA PECTINASE COMERCIAL DE Aspergillus niger LIVRE E IMOBILIZADA EM ESPUMA RÍGIDA DE POLIURETANO

Anais do Congresso Brasileiro de Engenharia Química em Iniciação Científica - Cobeq IC 2015, 2015

Research paper thumbnail of Synthesis of a hybrid polymer-inorganic biomimetic support incorporating in situ pectinase from Aspergillus niger ATCC 9642

Bioprocess and Biosystems Engineering, 2015

The hybrid alginate/gelatin/calcium oxalate (AGOCa) support was successfully synthesized through ... more The hybrid alginate/gelatin/calcium oxalate (AGOCa) support was successfully synthesized through the biomimetic mineralization method for immobilization in situ of a pectinolytic extract from Aspergillus niger ATCC 9642 via entrapment technique. The efficiency of immobilization reached 72.7 %. Sodium oxalate buffer (100 mM, pH 5.5) was selected as adjuvant of the immobilization process by allowing the formation of a calcified shell around the calcium alginate capsule, significantly increasing the stability to storage, thermal and recycling of the enzymatic immobilized pectinolytic extract. The pH and temperature for maximum activity were from 5.0 to 6.0 and 60 to 80 °C, respectively. The new hybrid support can be a potential alternative to obtain immobilized pectinases with properties for advantageous industrial applications.

Research paper thumbnail of Qualitative lead extraction from recycled lead-acid batteries slag

Journal of hazardous …, 2009

The pyrometallurgic process that the exhausted batteries are submitted for the recovery of metall... more The pyrometallurgic process that the exhausted batteries are submitted for the recovery of metallic lead generates great amount of a by-product called slag. The slag is composed mainly of iron ( approximately 60%) and lead ( approximately 6%), and this residue cannot be disposed in conventional landfill due to the high lead content. This work presents a new methodology for the extraction of lead from slag, based on the complexing effect of EDTA, a chelating ligand that has the ability to solubilize several heavy metals. As the iron (Fe(2+)/Fe(3+)) have a formation&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s constant with EDTA higher than the lead and is present in high concentrations in the samples, the fluoride ion (F(-)) was employed to mask the iron ions. The tests were carried out in a qualitative way, confirming the lead extraction by the formation of a yellow precipitate of lead iodide.

Research paper thumbnail of Flow-Injection Spectrophotometric Determination of Hydrazine

Microchemical Journal, 1997

Research paper thumbnail of Processo enzimático para produção de acetato de isoamila livre de solvente orgânico

Brazilian Journal of Food Research

Nos últimos anos, a crescente demanda por produtos naturais na indústria de alimentos incentivou ... more Nos últimos anos, a crescente demanda por produtos naturais na indústria de alimentos incentivou esforços notáveis no desenvolvimento de processos biotecnológicos para a produção de compostos aromatizantes. O presente estudo relata a maximização da produção de acetato de isoamila por esterificação de álcool isoamílico e ácido acético em um sistema isento de solventes usando duas lipases diferentes como catalisador. A lipase Novozyme NZL-102-LYO-HQ (Candida antarctica B imobilizada em poliuretano – PU) foi comparada com a comercializada Novozym 435 e foi avaliada em termos de desempenho, rendimento e estabilidade operacional. Os efeitos nas taxas de reação mostraram valores maximizados diferentes, empregando esses dois catalisadores, no entanto as condições reacionais no que se refere a razão molar do substrato (ácido acético: álcool isoamílico), massa de catalisador e tempo de reação foram distintos. Embora Novozym 435 exibisse maior conversão inicial com relação a NZL-102-LYO-HQ, a...

Research paper thumbnail of Yerba mate (Ilex paraguariensis St. Hil.) extract inhibits hand-rolled cornhusk cigarette smoke-induced oxidative pulmonary damage

Anais da Academia Brasileira de Ciências

The aim of this study was to investigate the effects of yerba mate (Ilex paraguariensis St. Hil.)... more The aim of this study was to investigate the effects of yerba mate (Ilex paraguariensis St. Hil.) extract (YME) on oxidative stress parameters and pathological changes in the lungs of mice chronically exposed to hand-rolled cornhusk cigarette (HRC) smoke. Twenty-four male Swiss mice were divided into four groups exposed to the following treatments: control (ambient air), HRC, YME, and HRC plus YME. The animals were exposed to four HRCs per session, with 3 sessions/day, every day for 30 days. Twenty-four hours after the last inhalation, the mice were killed, and the left lungs were removed. The results showed that HRC contains elevated levels of tin and carbon oxide, but less arsenic, cobalt, manganese, and selenium than commercial cigarettes. YME administration reversed fi brosis, alveolar enlargement, and hemorrhage induced by HRC smoke. In addition, the YME and HRC signifi cantly reduced the production of oxidants, oxidative damage and promoted a signifi cant increase in total thiol. In conclusion, exposure to HRC smoke compromised pulmonary histoarchitecture by promoting structural changes and increasing oxidative stress in tissues. However, concomitant treatment with YME regulated the redox state and reduced the harmful effects of HRC smoke exposure in the lungs.

Research paper thumbnail of Extração e recuperação de prata e mercúrio em efluentes gerados na determinação de DQO empregando métodos físico-químicos

Engenharia Sanitaria e Ambiental, 2008

Durante as análises de Demanda Química de Oxigênio (DQO) é gerado um efluente líquido que se cara... more Durante as análises de Demanda Química de Oxigênio (DQO) é gerado um efluente líquido que se caracteriza pela presença de elevadas concentrações de metais pesados (Hg, Ag, Cr e Fe). Visando à remoção seletiva destes metais, possibilitando suas reutilizações, foram avaliados diferentes agentes precipitantes (Cl-, Br-, I- e S= para a Ag e o Hg e NaOH, NH4OH e NaHCO3 para o Cr e o Fe). Para a Ag e o Hg os melhores resultados em termos de remoção e recuperação seletiva foram obtidos quando do emprego seqüencial dos íons cloreto e sulfeto. Devido à presença de Hg(I), se fez necessário o emprego de NH4OH para separar seletivamente a Ag, presente na forma de AgCl, precipitada concomitantemente com Hg(I) como Hg2Cl2. Para o Cr e o Fe foram obtidas remoções que satisfazem à legislação (FEPAM) para ambos os elementos, somente quando do emprego do NaOH como agente precipitante.

Research paper thumbnail of Study of the Relation between the Inorganic and Organic Material in the Air Pollution of the City of Caxias do Sul

The main objective of this work was the semi-quantitative evaluation of the influence of the conc... more The main objective of this work was the semi-quantitative evaluation of the influence of the concentrations of fine and coarse particulate matter (PM 2.5 and PM 10) and black carbon (BC) on the organic compound concentrations in the atmosphere of Caxias do Sul, a city in Rio Grande do Sul, the southernmost state of Brazil. The collection of the samples was carried out between August of 2006 and January of 2007. The periodic replacement of the cartridges and sampling filters was performed every other day (48 h sampling). An active sampler was used for the collection of the inorganic particulate matter, that means, PM 2.5 and PM 10 were sampled using stacked filter units that collect fine (d < 2.5 μm) and coarse (2.5 μm < d < 10 μm) particulate matter. The organic material was collected by a previously treated cotton cartridge. Both samplings (inorganic and organic matter) were performed at the same time and sampling point, with division of the air flux. The air was forced to pass through the two samplers by a vacuum pump. The inorganic particulate matter was characterized by gravimetry and reflectance. The tentative identification of the organic compounds was obtained by gas chromatography with mass spectrometry detection (GC-MS). The preliminary results suggest an inverse relation among the PM 10 concentration and the amounts of some organic compounds like 1H-indene, neridol and ethylphthalate. On the other hand, the maximum quantity of eburnamonine was detected at the same time as the maximum concentrations of BC. No correlations were found between the PM 2.5 concentrations and the amounts of organic compounds, in the samples studied.

Research paper thumbnail of Solid waste from tanneries as adsorbent for the removal of dyes in aqueous medium

Química Nova, 2005

... Technol. Biotechnol. 1991, 50, 257. [ Links ]. 26. McKay, G.; Allen, SJ; J. Sep. Process Tech... more ... Technol. Biotechnol. 1991, 50, 257. [ Links ]. 26. McKay, G.; Allen, SJ; J. Sep. Process Technol. 1983, 4, 1. [ Links ]. 27. Nicolet, L.; Rott, U.; Water Sci. ... 36. Hoinacki, E.; Gutheil, NC; Peles e Couros: origens, defeitos e industrialização, CIENTEC: Porto Alegre, 1978. [ Links ]. 37. ...

Research paper thumbnail of Preliminary Study of Some Plasticizers Compounds in Sewage Before and After the Treatment in a Sewage Treatment Plant

Chemical engineering transactions, 2008

Oliveira M., Dallago R.M., Dellanora R., and Nascimento I.F. Chemical Engineering Department, Uni... more Oliveira M., Dallago R.M., Dellanora R., and Nascimento I.F. Chemical Engineering Department, Universidade de Caxias do Sul, RS-Brazil Chemistry Department, URI – campus de Erechim, RS-Brazil Technological Center, URI – campus de Erechim, RS-Brazil Physics and Chemistry Department – Universidade de Caxias do Sul, Avenida Francisco Getúlio Vargas, 1130, CEP 95070-560, Caxias do Sul, RS-Brazil e-mail: inascimf@ucs.br

Research paper thumbnail of Eletrofloculação no tratamento de dejeto suíno submetido ao pré-tratamento de digestão anaeróbia

Research paper thumbnail of Desenvolvimento de catalisadores ambientais de Pd-W/gama-Al2O3 e Pd/Mo/gama-Al2O3

Research paper thumbnail of Decomposi��o catal�tica de �xidos de nitrog�nio

Research paper thumbnail of Adsorption of organic matter by inorganic particulate in air pollution

Air Pollution XVIII, 2010

Research paper thumbnail of Decomposição catalítica de óxidos de nitrogênio

Research paper thumbnail of Optimization of the methodology for lead extraction from waste contaminated with heavy metals

Environmental Technology, 2010

A sequential experimental design strategy is used to optimize the extraction of lead from slag. T... more A sequential experimental design strategy is used to optimize the extraction of lead from slag. The slag is composed mainly of iron (= 60%) and lead (= 6%), and cannot be disposed of in conventional landfill due to its high lead content. The extraction of lead is based on the complexing properties of ethylenediaminetetra-acetic acid (EDTA), the iron being masked with fluoride ions. Atomic absorption spectroscopy (AAS) has been used for monitoring iron and lead concentrations. In a first step, Plackett-Burman PB-12 experimental design was used for screening the variables and for selecting those to be used. Two central composite designs (CCDs) were then carried out to determine the optimal conditions for lead extraction. The optimized experimental conditions were established to be: contact time with the fluoride solution 30 min; particle size of slag between 150 and 600 microm; molecular concentration of fluoride solution 2.4 x 10(-3) mol and of EDTA 5 x 10(-4) mol; pH 1.5; 8 h contact time with the EDTA solution; and temperature 60 degrees C. Under these experimental conditions the lead content was reduced by 57% compared with the raw sample.

Research paper thumbnail of Enzymatic production of linalool esters in organic and solvent-free system

Bioprocess and Biosystems Engineering, 2009

This work investigated the influence of temperature, enzyme concentration, substrates molar ratio... more This work investigated the influence of temperature, enzyme concentration, substrates molar ratio, in the absence and presence of organic solvent, at two molar ratios of the substrates on the enzymatic production of linalil esters using the immobilized lipase Novozym 435 as catalyst, different acids and linalool and Ho-Sho essential oil as substrates. The best reaction conversion was obtained at the highest temperature (70 degrees C), for both solvent free (3.81%) and with solvent addition (2.25%), for a solvent to substrates molar ratio of 2:1, enzyme concentration of 5 wt% and acid to alcohol molar ratio of 1:1. The reaction kinetics revealed that Ho-Sho essential oil afforded the greatest conversions when compared with pure linalool. Higher linalil esters production were achieved after 10 h reaction (5.58%) in 2:1 solvent to substrates molar ratio, with enzyme concentration of 5 wt%, at 70 degrees C and anhydride to alcohol molar ratio of 1:1 using Ho-Sho essential oil as substrate.

Research paper thumbnail of Resíduos sólidos de curtumes como adsorventes para a remoção de corantes em meio aquoso

Química Nova, 2005

Recebido em 5/4/04; aceito em 9/9/04; publicado na web em 4/2/05 SOLID WASTE FROM TANNERIES AS AD... more Recebido em 5/4/04; aceito em 9/9/04; publicado na web em 4/2/05 SOLID WASTE FROM TANNERIES AS ADSORBENT FOR THE REMOVAL OF DYES IN AQUEOUS MEDIUM. The tanning process in the leather industry generates very high quantities of chromium-containing solid waste ("wet blue" leather). Environmental concerns and escalating landfill-costs are becoming increasingly serious problems for the leather industry and an alternative disposal is needed. In this work, we are presenting a novel application for this solid waste, which is the removal of organic contaminants from aqueous-solution. The adsorption isotherm of "wet blue" leather waste from the AUREA tanning company in Erechim-RS (Brazil) showed that this material presents high adsorption capacities of the reactive textile dyes.

Research paper thumbnail of AVALIAÇÃO DA ESTABILIDADE ENZIMÁTICA DO EXTRATO PECTINOLÍTICO DE Aspergillus niger ATCC 9642 IMOBILIZADO EM SUPORTE POLIMÉRICO-INORGÂNICO MINERALIZADO BIOMIMETICAMENTE

Anais do XX Congresso Brasileiro de Engenharia Química

Research paper thumbnail of EFEITO DA ESTABILIDADE DE ESTOCAGEM DA LIPASE COMERCIAL DE Candida antarctica B (CALB) NA FORMA LIVRE E IMOBILIZADA POR CONFINAMENTO EM SUPORTE DE POLIURETANO

Anais do XX Congresso Brasileiro de Engenharia Química, 2015

Research paper thumbnail of ESTUDO DA TERMORRESISTÊNCIA DA PECTINASE COMERCIAL DE Aspergillus niger LIVRE E IMOBILIZADA EM ESPUMA RÍGIDA DE POLIURETANO

Anais do Congresso Brasileiro de Engenharia Química em Iniciação Científica - Cobeq IC 2015, 2015

Research paper thumbnail of Synthesis of a hybrid polymer-inorganic biomimetic support incorporating in situ pectinase from Aspergillus niger ATCC 9642

Bioprocess and Biosystems Engineering, 2015

The hybrid alginate/gelatin/calcium oxalate (AGOCa) support was successfully synthesized through ... more The hybrid alginate/gelatin/calcium oxalate (AGOCa) support was successfully synthesized through the biomimetic mineralization method for immobilization in situ of a pectinolytic extract from Aspergillus niger ATCC 9642 via entrapment technique. The efficiency of immobilization reached 72.7 %. Sodium oxalate buffer (100 mM, pH 5.5) was selected as adjuvant of the immobilization process by allowing the formation of a calcified shell around the calcium alginate capsule, significantly increasing the stability to storage, thermal and recycling of the enzymatic immobilized pectinolytic extract. The pH and temperature for maximum activity were from 5.0 to 6.0 and 60 to 80 °C, respectively. The new hybrid support can be a potential alternative to obtain immobilized pectinases with properties for advantageous industrial applications.

Research paper thumbnail of Qualitative lead extraction from recycled lead-acid batteries slag

Journal of hazardous …, 2009

The pyrometallurgic process that the exhausted batteries are submitted for the recovery of metall... more The pyrometallurgic process that the exhausted batteries are submitted for the recovery of metallic lead generates great amount of a by-product called slag. The slag is composed mainly of iron ( approximately 60%) and lead ( approximately 6%), and this residue cannot be disposed in conventional landfill due to the high lead content. This work presents a new methodology for the extraction of lead from slag, based on the complexing effect of EDTA, a chelating ligand that has the ability to solubilize several heavy metals. As the iron (Fe(2+)/Fe(3+)) have a formation&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s constant with EDTA higher than the lead and is present in high concentrations in the samples, the fluoride ion (F(-)) was employed to mask the iron ions. The tests were carried out in a qualitative way, confirming the lead extraction by the formation of a yellow precipitate of lead iodide.

Research paper thumbnail of Flow-Injection Spectrophotometric Determination of Hydrazine

Microchemical Journal, 1997

Research paper thumbnail of Processo enzimático para produção de acetato de isoamila livre de solvente orgânico

Brazilian Journal of Food Research

Nos últimos anos, a crescente demanda por produtos naturais na indústria de alimentos incentivou ... more Nos últimos anos, a crescente demanda por produtos naturais na indústria de alimentos incentivou esforços notáveis no desenvolvimento de processos biotecnológicos para a produção de compostos aromatizantes. O presente estudo relata a maximização da produção de acetato de isoamila por esterificação de álcool isoamílico e ácido acético em um sistema isento de solventes usando duas lipases diferentes como catalisador. A lipase Novozyme NZL-102-LYO-HQ (Candida antarctica B imobilizada em poliuretano – PU) foi comparada com a comercializada Novozym 435 e foi avaliada em termos de desempenho, rendimento e estabilidade operacional. Os efeitos nas taxas de reação mostraram valores maximizados diferentes, empregando esses dois catalisadores, no entanto as condições reacionais no que se refere a razão molar do substrato (ácido acético: álcool isoamílico), massa de catalisador e tempo de reação foram distintos. Embora Novozym 435 exibisse maior conversão inicial com relação a NZL-102-LYO-HQ, a...

Research paper thumbnail of Yerba mate (Ilex paraguariensis St. Hil.) extract inhibits hand-rolled cornhusk cigarette smoke-induced oxidative pulmonary damage

Anais da Academia Brasileira de Ciências

The aim of this study was to investigate the effects of yerba mate (Ilex paraguariensis St. Hil.)... more The aim of this study was to investigate the effects of yerba mate (Ilex paraguariensis St. Hil.) extract (YME) on oxidative stress parameters and pathological changes in the lungs of mice chronically exposed to hand-rolled cornhusk cigarette (HRC) smoke. Twenty-four male Swiss mice were divided into four groups exposed to the following treatments: control (ambient air), HRC, YME, and HRC plus YME. The animals were exposed to four HRCs per session, with 3 sessions/day, every day for 30 days. Twenty-four hours after the last inhalation, the mice were killed, and the left lungs were removed. The results showed that HRC contains elevated levels of tin and carbon oxide, but less arsenic, cobalt, manganese, and selenium than commercial cigarettes. YME administration reversed fi brosis, alveolar enlargement, and hemorrhage induced by HRC smoke. In addition, the YME and HRC signifi cantly reduced the production of oxidants, oxidative damage and promoted a signifi cant increase in total thiol. In conclusion, exposure to HRC smoke compromised pulmonary histoarchitecture by promoting structural changes and increasing oxidative stress in tissues. However, concomitant treatment with YME regulated the redox state and reduced the harmful effects of HRC smoke exposure in the lungs.