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Papers by Michelle Brugnera

Pollutants’ degradation has been a very important topic in environmental research. The present pa... more Pollutants’ degradation has been a very important topic in environmental research. The present paper presents an approach to degrade atrazine, an environmentally harmful pesticide. Ti/TiO2 nanotube electrodes modified by porphyrins were prepared for photolysis (PH), photocatalysis (PC), and photoelectrocatalysis (PEC). Manganese- and free base porphyrin were studied, and it was possible to verify the kinetic model more suitable for each system. Unfortunately, Mn-porphyrins had an inhibitory effect on the ATZ degradation activity by Ti/TiO2 nanotubes electrodes. Although the Ti/TiO2-free base porphyrin under the PEC experiment (using surface water from a Brazilian river) did not lead to the best degradation system, we could verify the formed products, which have been not described for other porphyrin-mediated atrazine degradation, are equal or more toxic than the original atrazine. We highlight the importance of verifying the products formed in the degradation systems and determining...

Applications of the Voltammetry, 2017

Since 1856 when W. H. Perkin synthesized the first synthetic dye (Mauveine), a wide variety of co... more Since 1856 when W. H. Perkin synthesized the first synthetic dye (Mauveine), a wide variety of colors and shades are produced and used in several commercial products. The occurrence in water and wastewater has gained controversy regarding their toxicity and mutagenicity and it has been regulation by several regulatory agencies. Thus, analytical methods able to determine these colorings in several matrices with high sensitive and robust enough are relevant. Among several analytical methods, the use of electroanalytical methods, especially the voltammetric techniques, are of great interest due to the high selectivity, sensitivity, use of low quantity of sample, little or without sample treatment, and low waste generation, which contributes to reduced environmental impact. Over the past decades, the technical based on current-potential curves by using of static electrodes have gained considerable progress, as minimizing the effect of capacitive current and the possibility of pre-concentration of the analyte at the electrode surface, which has reflected in lower detection levels. The present work gives an overview about the analytical methods available in literature focusing on electroanalysis of dyes by using voltammetric techniques. The advances of the electroanalytical techniques and the use of different modifiers to increase sensitivity and selectivity are reviewed.

Environmental Technology, 2019

Mycobacterium tuberculosis is highly infectious, persistent and has been detected in more than on... more Mycobacterium tuberculosis is highly infectious, persistent and has been detected in more than one quarter of the world's population. It is notoriously resistant to sterilization and disinfection procedures, largely due to an unusual hydrophobic cell wall and effective defense mechanisms against oxidative stress. This work shows an effective method to reduce M. tuberculosis quantity in water by using Ti/TiO2 nanotubes electrodes bare and coated with Ag nanoparticles by using photoelectrocatalytic oxidation process. The results have indicated 99.999% of inactivation of a solution spiked with standard and resistant strains of 1 x 10 4 CFU mL-1 M. tuberculosis after 5 min of treatment at Ti/TiO2 photoanode in 0.05 mol L-1 Na2SO4 (pH 6) under applied potential of +1.5 V versus Ag/AgCl and UV irradiation. The mycobacteria degradation was monitored by dissolved total organic carbon (TOC) removal, carbohydrate release, chromatography coupled to mass spectroscopy measurements and it is slightly superior to photocatalysis and photolysis processes. All the results corroborated with the complete inactivation and degradation of the byproducts generated during cell lysis.

Journal of Hazardous Materials, 2019

Martins DC, Efficient atrazine degradation catalyzed by manganese porphyrins: determination of at... more Martins DC, Efficient atrazine degradation catalyzed by manganese porphyrins: determination of atrazine degradation products and their toxicity evaluation by human blood cells test models,

Current Opinion in Electrochemistry, 2019

Color is an important element of the final product of many industries, including the textile, lea... more Color is an important element of the final product of many industries, including the textile, leather, food, cosmetic, pharmaceutical, plastic, and fuel-marking industries. Dyes are complex organic substances with chromophore and auxochromic groups, which can be electrochemically oxidized and/ or reduced; this constitutes the basis of their electroanalytical determination. Despite some controversies, dyes pose risks to living organisms, especially after biotransformation, as the metabolites can be more toxic, mutagenic, or carcinogenic than the original dyes. The present work provides a brief overview of the recent progress in electrochemical sensors used for dye detection in diversified matrices. Sensors developed over the recent years are characterized by high sensitivity and selectivity, besides being economically advantageous once they allow the use of little or no clean-up samples in portable and miniaturized systems.

Journal of environmental science and health. Part. B, Pesticides, food contaminants, and agricultural wastes, Jan 3, 2018

In this study, the quality of surface water in the headwaters of São Lourenço River in Mato Gross... more In this study, the quality of surface water in the headwaters of São Lourenço River in Mato Grosso, Brazil, was evaluated in relation to contamination by pesticides. For this purpose, samples were collected between December 2015 and June 2016 by grab sampling and by passive sampling using an integrative polar organic compound sampler installed in the field during four 14-day cycles between March and June 2016. The analyses were performed by gas chromatography (CG/MS) and by liquid chromatography (UPLC-MS/MS). The results showed the detection of two pesticides (atrazine and pyraclostrobin) of the five analyzed by passive sampling and eight active principles among the 20 analyzed (malathion, diuron, carbofuran, carbendazim, trifluralin, imidacloprid, metolachlor, and acetamiprid) by grab sampling. The detection of 10 pesticides, even almost a decade after the beginning of a recovery process of the ciliary forest, confirms the headwaters' vulnerability to these contaminants and pas...

Journal of the Brazilian Chemical Society, 2017

The present work investigates the use of W/WO 3 electrodes prepared by electrochemical anodizatio... more The present work investigates the use of W/WO 3 electrodes prepared by electrochemical anodization applied in the photoelectrocatalytic disinfection of Candida parapsilosis using ultraviolet-visible (UV-Vis) and visible irradiation. The core objective of this work lies in describing a novel approach involving the use of chloride as supporting electrolyte, aiming at achieving a faster inactivation and towards understanding its behavior in water containing high chloride content. The best experimental conditions were found to be at pH 7.0 and 0.1 mol L-1 NaCl when the photoelectrode was biased at 1.5 V (vs. Ag/AgCl) illuminated by both UV-Vis and visible light. It is suggested that charges photogenerated on the electrode surface give rise preferably to HO•, known to be powerful oxidant that causes the total inactivation of the microorganism (1 min of treatment) while engendering around 84% of mineralization of organic matter released from the cell damage following 120 min of treatment.

Actinobacteria - Basics and Biotechnological Applications, 2016

Actinobacteria, such as Mycobacterium, that constitute one of the main phyla within the bacteria ... more Actinobacteria, such as Mycobacterium, that constitute one of the main phyla within the bacteria and some genus of this phylum are reported to be a pathogen of or associated with nosocomial infections and pseudoinfections promoting health risks for immunocompromised people, particularly AIDS patients. They are also related to lower quality of surface water due to their odor production (Actinomycineae and Streptomycetaceae). These bacteria have been isolated from hospital water distribution systems, municipal drinking water, freshwater, and among other environmental samples. Their biofilm formation, amoeba-associated lifestyle, and resistance to chlorine/ozone have been recognized as important factors that contribute to persistence of these bacteria in water distribution systems. Research for new disinfection methods that are able to promote complete inactivation of these bacteria has currently increased. Among them is the use of advanced oxidation process that has demonstrated promising results; the production of ⋅OH radicals with high oxidizing power are capable to kill bacteria and can also destroy the products generated from lyse cell. The goal of the present work is to review the main processes based on advanced oxidation process that are able to promote actinobacterium disinfection. The fundaments of this process are also reviewed. Special emphasis was done for the photocatalysis and photoelectrocatalysis methods and the phenomena occurring at the electrode/electrolyte interface.

Electrocatalysis, 2015

The great versatility of semiconductor materials and the possibility of generation of electrons, ... more The great versatility of semiconductor materials and the possibility of generation of electrons, holes, hydroxyl radicals, and/or superoxide radicals have increased the applicability of photoelectrocatalysis dramatically in the contemporary world. Photoelectrocatalysis takes advantage of the heterogeneous photocatalytic process by applying a biased potential on a photoelectrode in which the catalyst is supported. This configuration allows more effectiveness of the separation of photogenerated charges due to light irradiation with energy being higher compared to that of the band gap energy of the semiconductor, which thereby leads to an increase in the lifetime of the electron-hole pairs. This work presents a compiled and critical review of photoelectrocatalysis, trends and future prospects of the technique applied in environmental protection studies, hydrogen generation, and water disinfection. Special attention will be focused on the applications of TiO 2 and the production of nanometric morphologies with a great improvement in the photocatalyst properties useful for the degradation of organic pollutants, the reduction of inorganic contaminants, the conversion of CO 2 , microorganism inactivation, and water splitting for hydrogen generation. Keywords Photoelectrocatalytic degradation of organics. Water splitting. photoelectrocatalytic CO 2 reduction. TiO 2 applied in disinfection. TiO 2 nanotubes. Photoelectrosynthesis

Eclética Química, 2006

Eletrodos de carbono vítreo foram modificados com filmes de poli ácido glutâmico (PAG) pela eletr... more Eletrodos de carbono vítreo foram modificados com filmes de poli ácido glutâmico (PAG) pela eletropolimerização do ácido glutâmico em tampão fosfato pH 7,0, utilizando-se varreduras sucessivas de potencial entre 0,8 a +2,0 V. Os eletrodos modificados foram aplicados na determinação de hidrazina, a qual é pré-concentrada na superfície através da interação entre grupos carboxílicos livres no filme e grupo amino da hidrazina. Embora a hidrazina não seja oxidada em intervalo útil de potencial sobre eletrodo convencional, no eletrodo modificado caracteriza-se pelo pico de oxidação em potencial de +0,57 V usado para fins analíticos. Gráfico de calibração linear foi obtido no intervalo de concentração entre 4 x 10-5 a 1 x 10-3 mol L-1, usando voltametria de pulso diferencial. O limite de detecção foi de 1,2 x 10-6 mol L-1. O método foi aplicado para a determinação de hidrazina em amostras coletadas de água de caldeira com recuperação de 94%.

The present work describes a fast, simple, and economic method for electroanalytical detection of... more The present work describes a fast, simple, and economic method for electroanalytical detection of mycolic acids (MA) present in the cell envelope of Mycobacterium, Corynebacterium, Nocardia, and Rhodococcus. MA are pre-concentrated on a glassy carbon electrode modified with a poly-L-lysine film, resulting in a well-defined reduction wave at-0.73 V (vs. Ag/AgCl) and being the base for detection and quantification of bacteria, like Mycobacterium smegmatis, used as model in this work. The method was optimized and analytical curves were constructed for Mycobacterium smegmatis by using square wave voltammetry. The method offers a detection limit of 5.9  10 colony forming units (CFU) mL-1 , and the reproducibility for 10 measurements at 1.4  10 2 CFU mL-1 showed a standard deviation of 1.8%. The method was successfully applied for detection of MA in water samples as indirect measure of the presence of Mycobacteria.

Water Research, 2013

Nontuberculous mycobacteria are resistant to conventional water treatment; indeed, they have been... more Nontuberculous mycobacteria are resistant to conventional water treatment; indeed, they have been recovered from a wide variety of environmental sources. Here, we applied the photoelectrocatalytic technique using a Ti/TiO2-Ag photoanode to inactivate mycobacteria. For a mycobacteria population of 5 × 10(8) CFU mL(-1), we achieved 99.9 and 99.8% inactivation of Mycobacterium kansasii and Mycobacterium avium with rate constant of 6.2 × 10(-3) and 4.2 × 10(-3) min(-1), respectively, after 240 min. We compared the proposed method with the photolytic and photocatalytic methods. Using a mycobacteria population of 7.5 × 10(4) CFU mL(-1), the proposed Ti/TiO2-Ag photoanode elicited total mycobacteria inactivation within 3 min of treatment; the presence of Ag nanoparticles in the electrode provided 1.5 larger degradation rate constant as compared with the Ti/TiO2 anode (1.75 × 10(-2) for M. kansassi and 1.98 × 10(-2) for M. avium). We monitored the degradation of the metabolites released during cellular lysis by TOC removal, sugar release, chromatography, and mass spectrometry measurements; photoelectrocatalysis and Ti/TiO2-Ag photoanodes furnished the best results.

Journal of Chemical Technology & Biotechnology, 2013

BACKGROUND: Rapid-growing mycobacteria are difficult to eradicate using common disinfection pract... more BACKGROUND: Rapid-growing mycobacteria are difficult to eradicate using common disinfection practices, when compared with coliforms. They are resistant to chlorination, which is commonly used in swimming pool and drinking water treatment. They also resist treatment with glutaraldehyde (GA), benzalkonium chloride, organomercury compounds, chlorohexidine, and even autoclavation. So, the present work describes the development of a new treatment method for Mycobacterium disinfection based on phoelectrocatalytical oxidation at Ti/TiO 2 nanotubes electrodes, which could be a promising alternative for its inactivation in a short treatment time. RESULTS: Nanotubular TiO 2 was grown on Ti surface using electrochemical anodization in fluoride medium and applied to photoelectrocatalytic inactivation of 10 3 CFU mL-1 Mycobaterium fortuitum, M. chelonae, and M. abscessus, which was achieved after 3 min treatment. The metabolites released during cellular lysis were also degraded with 240 min of photoelectrocatalytical treatment, as monitored by mass spectroscopy measurements. Mineralization was greater than 70% under optimum conditions. The photoelectrocatalytic method gave better results than the photolytic and photocatalytic techniques. The method provided the most efficient mycobacterial inactivation and TOC removal rate, thus being the best to disinfect mycobacterium-infected water. CONCLUSION: Photoelectrodes based on Ti/TiO 2 nanotubes prepared by electrochemical anodization are a powerful alternative to disinfect mycobacterium-contaminated water.

Journal of Chemical Technology & Biotechnology, 2013

BACKGROUND: Rapid-growing mycobacteria are difficult to eradicate using common disinfection pract... more BACKGROUND: Rapid-growing mycobacteria are difficult to eradicate using common disinfection practices, when compared with coliforms. They are resistant to chlorination, which is commonly used in swimming pool and drinking water treatment. They also resist treatment with glutaraldehyde (GA), benzalkonium chloride, organomercury compounds, chlorohexidine, and even autoclavation. So, the present work describes the development of a new treatment method for Mycobacterium disinfection based on phoelectrocatalytical oxidation at Ti/TiO 2 nanotubes electrodes, which could be a promising alternative for its inactivation in a short treatment time. RESULTS: Nanotubular TiO 2 was grown on Ti surface using electrochemical anodization in fluoride medium and applied to photoelectrocatalytic inactivation of 10 3 CFU mL-1 Mycobaterium fortuitum, M. chelonae, and M. abscessus, which was achieved after 3 min treatment. The metabolites released during cellular lysis were also degraded with 240 min of photoelectrocatalytical treatment, as monitored by mass spectroscopy measurements. Mineralization was greater than 70% under optimum conditions. The photoelectrocatalytic method gave better results than the photolytic and photocatalytic techniques. The method provided the most efficient mycobacterial inactivation and TOC removal rate, thus being the best to disinfect mycobacterium-infected water. CONCLUSION: Photoelectrodes based on Ti/TiO 2 nanotubes prepared by electrochemical anodization are a powerful alternative to disinfect mycobacterium-contaminated water.

Electrochimica Acta, 2012

ABSTRACT TiO2 nanotubular array electrodes coated with 16% (w/w) Ag nanoparticles (Ti/TiO2-Ag) ha... more ABSTRACT TiO2 nanotubular array electrodes coated with 16% (w/w) Ag nanoparticles (Ti/TiO2-Ag) have shown excellent performance in the disinfection of water containing Mycobacterium smegmatis. Photoelectrocatalytic disinfection of M. smegmatis 5.1 × 103 Colony Forming Units (CFU) mL−1 in 0.05 M Na2SO4 (pH 6), applied potential of +1.5 V versus Ag/AgCl and UV irradiation promoted 100% inactivation after 3 min of treatment. Mycobacteria degradation was also monitored by TOC removal, sugar release, chromatography and mass spectroscopy measurements. All analytical methods used confirmed that there was complete inactivation of mycobacteria and degradation of the by-products generated during cellular lyses by the proposed method.

Chemosphere, 2010

Photoelectrocatalytic oxidation of 0.1mM of Bisphenol A (BPA) leads to 100% of degradation monito... more Photoelectrocatalytic oxidation of 0.1mM of Bisphenol A (BPA) leads to 100% of degradation monitored by liquid chromatography with diode array optical detection (limit 1microgL(-1)) and 100% TOC removal. Optimum performance was obtained using TiO(2) nanotubular array (NTA) electrodes, grown by anodization of Ti foil in 0.25wt.% NH(4)F and a mixture of glycerol and water (ratio 90:10vol.%) using an applied voltage of 20V for 50h. The effects of supporting electrolyte, pH, applied bias potential and BPA concentration were evaluated as to their effect on the BPA degradation kinetics and the best condition was found to be 0.1M Na(2)SO(4) at pH 6 as supporting electrolyte and applied bias potential of +1.5V vs. Ag/AgCl under UV irradiation. Our findings indicate that TiO(2) NTAs prepared by anodization are versatile and efficient photocatalysts for the degradation of endocrine disruptors.

... Um pico bem definido em + 0,57 V é observado, o qual é atribuído à oxidação do grupo amina da... more ... Um pico bem definido em + 0,57 V é observado, o qual é atribuído à oxidação do grupo amina da hidrazona formada e imobilizada no eletrodo, após reação direta entre os grupos carboxílicos do poli aminoácido eo grupo amina da hidrazina. ... [10] A. Salimi, K. Abdi, Talanta 63 ...

Talanta, 2016

This paper addresses a sensitive method for the detection of mycobacteria in hemodialysis water s... more This paper addresses a sensitive method for the detection of mycobacteria in hemodialysis water samples based on a magneto-actuated immunoassay with optical readout. In this approach, micro (2.8 μm) sized magnetic particles were modified with an antibody against the lipoarabinomannan (LAM) located in the mycobacterial cell wall. The system relies on the immunocapturing of the mycobacteria with the tailored antiLAM magnetic particles to pre-concentrate the bacteria from the hemodialysis samples throughout an immunological reaction. The performance of the immunomagnetic separation on the magnetic carrier was evaluated using confocal microscopy to study the binding pattern, as well as a magneto-actuated immunoassay with optical readout for the rapid detection of the bacteria in spiked hemodialysis samples. In this approach, the antiLAM polyclonal antibody was labeled with fluorescein isothiocyanate. The optical readout was achieved by the incubation with a secondary anti-fluorescein antibody labeled with peroxidase as optical reporter. The magneto-actuated immunoassay was able to detect mycobacteria contamination in hemodialysis water at a limit of detection of 13 CFU mL À 1 in a total assay time of 3 h without any previous culturing pre-enrichment step.

Applied Catalysis A: General, 2016

Photoelectrocatalysis (PEC) has become an attractive technology to disinfect microorganisms from ... more Photoelectrocatalysis (PEC) has become an attractive technology to disinfect microorganisms from aqueous environments because of its ability to degrade microorganisms without producing any harmful by-products. PEC methodology was applied to inactivate Candida parapsilosis sensu stricto in planktonic and biofilm cells, and its efficiency was compared to that of photolytic and photocatalytic treatment. In the case of planktonic (free-floating) cells, PEC promoted the inactivation of 10 6 CFU mL −1 after 3 min of treatment, and the addition of silver nanoparticles to the Ti/TiO 2 electrodes had virtually no effect on the disinfection period, although it caused a decrease by a factor of 1.5 in the mineralization efficiency. After 60, 10 and 60 min of treatment, PEC methodology reduced 10 6 CFU mL −1 on fungal biofilms and provided 71, 91 and 92% mineralization for biofilm cells performed on polyvinyl chloride (PVC), silicone, and polytetrafluoroethylene (PTFE), respectively. These results indicated that PEC is a promising process for disinfection of water contaminated with C. parapsilosis sensu stricto in both planktonic and biofilm cells.

Pollutants’ degradation has been a very important topic in environmental research. The present pa... more Pollutants’ degradation has been a very important topic in environmental research. The present paper presents an approach to degrade atrazine, an environmentally harmful pesticide. Ti/TiO2 nanotube electrodes modified by porphyrins were prepared for photolysis (PH), photocatalysis (PC), and photoelectrocatalysis (PEC). Manganese- and free base porphyrin were studied, and it was possible to verify the kinetic model more suitable for each system. Unfortunately, Mn-porphyrins had an inhibitory effect on the ATZ degradation activity by Ti/TiO2 nanotubes electrodes. Although the Ti/TiO2-free base porphyrin under the PEC experiment (using surface water from a Brazilian river) did not lead to the best degradation system, we could verify the formed products, which have been not described for other porphyrin-mediated atrazine degradation, are equal or more toxic than the original atrazine. We highlight the importance of verifying the products formed in the degradation systems and determining...

Applications of the Voltammetry, 2017

Since 1856 when W. H. Perkin synthesized the first synthetic dye (Mauveine), a wide variety of co... more Since 1856 when W. H. Perkin synthesized the first synthetic dye (Mauveine), a wide variety of colors and shades are produced and used in several commercial products. The occurrence in water and wastewater has gained controversy regarding their toxicity and mutagenicity and it has been regulation by several regulatory agencies. Thus, analytical methods able to determine these colorings in several matrices with high sensitive and robust enough are relevant. Among several analytical methods, the use of electroanalytical methods, especially the voltammetric techniques, are of great interest due to the high selectivity, sensitivity, use of low quantity of sample, little or without sample treatment, and low waste generation, which contributes to reduced environmental impact. Over the past decades, the technical based on current-potential curves by using of static electrodes have gained considerable progress, as minimizing the effect of capacitive current and the possibility of pre-concentration of the analyte at the electrode surface, which has reflected in lower detection levels. The present work gives an overview about the analytical methods available in literature focusing on electroanalysis of dyes by using voltammetric techniques. The advances of the electroanalytical techniques and the use of different modifiers to increase sensitivity and selectivity are reviewed.

Environmental Technology, 2019

Mycobacterium tuberculosis is highly infectious, persistent and has been detected in more than on... more Mycobacterium tuberculosis is highly infectious, persistent and has been detected in more than one quarter of the world's population. It is notoriously resistant to sterilization and disinfection procedures, largely due to an unusual hydrophobic cell wall and effective defense mechanisms against oxidative stress. This work shows an effective method to reduce M. tuberculosis quantity in water by using Ti/TiO2 nanotubes electrodes bare and coated with Ag nanoparticles by using photoelectrocatalytic oxidation process. The results have indicated 99.999% of inactivation of a solution spiked with standard and resistant strains of 1 x 10 4 CFU mL-1 M. tuberculosis after 5 min of treatment at Ti/TiO2 photoanode in 0.05 mol L-1 Na2SO4 (pH 6) under applied potential of +1.5 V versus Ag/AgCl and UV irradiation. The mycobacteria degradation was monitored by dissolved total organic carbon (TOC) removal, carbohydrate release, chromatography coupled to mass spectroscopy measurements and it is slightly superior to photocatalysis and photolysis processes. All the results corroborated with the complete inactivation and degradation of the byproducts generated during cell lysis.

Journal of Hazardous Materials, 2019

Martins DC, Efficient atrazine degradation catalyzed by manganese porphyrins: determination of at... more Martins DC, Efficient atrazine degradation catalyzed by manganese porphyrins: determination of atrazine degradation products and their toxicity evaluation by human blood cells test models,

Current Opinion in Electrochemistry, 2019

Color is an important element of the final product of many industries, including the textile, lea... more Color is an important element of the final product of many industries, including the textile, leather, food, cosmetic, pharmaceutical, plastic, and fuel-marking industries. Dyes are complex organic substances with chromophore and auxochromic groups, which can be electrochemically oxidized and/ or reduced; this constitutes the basis of their electroanalytical determination. Despite some controversies, dyes pose risks to living organisms, especially after biotransformation, as the metabolites can be more toxic, mutagenic, or carcinogenic than the original dyes. The present work provides a brief overview of the recent progress in electrochemical sensors used for dye detection in diversified matrices. Sensors developed over the recent years are characterized by high sensitivity and selectivity, besides being economically advantageous once they allow the use of little or no clean-up samples in portable and miniaturized systems.

Journal of environmental science and health. Part. B, Pesticides, food contaminants, and agricultural wastes, Jan 3, 2018

In this study, the quality of surface water in the headwaters of São Lourenço River in Mato Gross... more In this study, the quality of surface water in the headwaters of São Lourenço River in Mato Grosso, Brazil, was evaluated in relation to contamination by pesticides. For this purpose, samples were collected between December 2015 and June 2016 by grab sampling and by passive sampling using an integrative polar organic compound sampler installed in the field during four 14-day cycles between March and June 2016. The analyses were performed by gas chromatography (CG/MS) and by liquid chromatography (UPLC-MS/MS). The results showed the detection of two pesticides (atrazine and pyraclostrobin) of the five analyzed by passive sampling and eight active principles among the 20 analyzed (malathion, diuron, carbofuran, carbendazim, trifluralin, imidacloprid, metolachlor, and acetamiprid) by grab sampling. The detection of 10 pesticides, even almost a decade after the beginning of a recovery process of the ciliary forest, confirms the headwaters' vulnerability to these contaminants and pas...

Journal of the Brazilian Chemical Society, 2017

The present work investigates the use of W/WO 3 electrodes prepared by electrochemical anodizatio... more The present work investigates the use of W/WO 3 electrodes prepared by electrochemical anodization applied in the photoelectrocatalytic disinfection of Candida parapsilosis using ultraviolet-visible (UV-Vis) and visible irradiation. The core objective of this work lies in describing a novel approach involving the use of chloride as supporting electrolyte, aiming at achieving a faster inactivation and towards understanding its behavior in water containing high chloride content. The best experimental conditions were found to be at pH 7.0 and 0.1 mol L-1 NaCl when the photoelectrode was biased at 1.5 V (vs. Ag/AgCl) illuminated by both UV-Vis and visible light. It is suggested that charges photogenerated on the electrode surface give rise preferably to HO•, known to be powerful oxidant that causes the total inactivation of the microorganism (1 min of treatment) while engendering around 84% of mineralization of organic matter released from the cell damage following 120 min of treatment.

Actinobacteria - Basics and Biotechnological Applications, 2016

Actinobacteria, such as Mycobacterium, that constitute one of the main phyla within the bacteria ... more Actinobacteria, such as Mycobacterium, that constitute one of the main phyla within the bacteria and some genus of this phylum are reported to be a pathogen of or associated with nosocomial infections and pseudoinfections promoting health risks for immunocompromised people, particularly AIDS patients. They are also related to lower quality of surface water due to their odor production (Actinomycineae and Streptomycetaceae). These bacteria have been isolated from hospital water distribution systems, municipal drinking water, freshwater, and among other environmental samples. Their biofilm formation, amoeba-associated lifestyle, and resistance to chlorine/ozone have been recognized as important factors that contribute to persistence of these bacteria in water distribution systems. Research for new disinfection methods that are able to promote complete inactivation of these bacteria has currently increased. Among them is the use of advanced oxidation process that has demonstrated promising results; the production of ⋅OH radicals with high oxidizing power are capable to kill bacteria and can also destroy the products generated from lyse cell. The goal of the present work is to review the main processes based on advanced oxidation process that are able to promote actinobacterium disinfection. The fundaments of this process are also reviewed. Special emphasis was done for the photocatalysis and photoelectrocatalysis methods and the phenomena occurring at the electrode/electrolyte interface.

Electrocatalysis, 2015

The great versatility of semiconductor materials and the possibility of generation of electrons, ... more The great versatility of semiconductor materials and the possibility of generation of electrons, holes, hydroxyl radicals, and/or superoxide radicals have increased the applicability of photoelectrocatalysis dramatically in the contemporary world. Photoelectrocatalysis takes advantage of the heterogeneous photocatalytic process by applying a biased potential on a photoelectrode in which the catalyst is supported. This configuration allows more effectiveness of the separation of photogenerated charges due to light irradiation with energy being higher compared to that of the band gap energy of the semiconductor, which thereby leads to an increase in the lifetime of the electron-hole pairs. This work presents a compiled and critical review of photoelectrocatalysis, trends and future prospects of the technique applied in environmental protection studies, hydrogen generation, and water disinfection. Special attention will be focused on the applications of TiO 2 and the production of nanometric morphologies with a great improvement in the photocatalyst properties useful for the degradation of organic pollutants, the reduction of inorganic contaminants, the conversion of CO 2 , microorganism inactivation, and water splitting for hydrogen generation. Keywords Photoelectrocatalytic degradation of organics. Water splitting. photoelectrocatalytic CO 2 reduction. TiO 2 applied in disinfection. TiO 2 nanotubes. Photoelectrosynthesis

Eclética Química, 2006

Eletrodos de carbono vítreo foram modificados com filmes de poli ácido glutâmico (PAG) pela eletr... more Eletrodos de carbono vítreo foram modificados com filmes de poli ácido glutâmico (PAG) pela eletropolimerização do ácido glutâmico em tampão fosfato pH 7,0, utilizando-se varreduras sucessivas de potencial entre 0,8 a +2,0 V. Os eletrodos modificados foram aplicados na determinação de hidrazina, a qual é pré-concentrada na superfície através da interação entre grupos carboxílicos livres no filme e grupo amino da hidrazina. Embora a hidrazina não seja oxidada em intervalo útil de potencial sobre eletrodo convencional, no eletrodo modificado caracteriza-se pelo pico de oxidação em potencial de +0,57 V usado para fins analíticos. Gráfico de calibração linear foi obtido no intervalo de concentração entre 4 x 10-5 a 1 x 10-3 mol L-1, usando voltametria de pulso diferencial. O limite de detecção foi de 1,2 x 10-6 mol L-1. O método foi aplicado para a determinação de hidrazina em amostras coletadas de água de caldeira com recuperação de 94%.

The present work describes a fast, simple, and economic method for electroanalytical detection of... more The present work describes a fast, simple, and economic method for electroanalytical detection of mycolic acids (MA) present in the cell envelope of Mycobacterium, Corynebacterium, Nocardia, and Rhodococcus. MA are pre-concentrated on a glassy carbon electrode modified with a poly-L-lysine film, resulting in a well-defined reduction wave at-0.73 V (vs. Ag/AgCl) and being the base for detection and quantification of bacteria, like Mycobacterium smegmatis, used as model in this work. The method was optimized and analytical curves were constructed for Mycobacterium smegmatis by using square wave voltammetry. The method offers a detection limit of 5.9  10 colony forming units (CFU) mL-1 , and the reproducibility for 10 measurements at 1.4  10 2 CFU mL-1 showed a standard deviation of 1.8%. The method was successfully applied for detection of MA in water samples as indirect measure of the presence of Mycobacteria.

Water Research, 2013

Nontuberculous mycobacteria are resistant to conventional water treatment; indeed, they have been... more Nontuberculous mycobacteria are resistant to conventional water treatment; indeed, they have been recovered from a wide variety of environmental sources. Here, we applied the photoelectrocatalytic technique using a Ti/TiO2-Ag photoanode to inactivate mycobacteria. For a mycobacteria population of 5 × 10(8) CFU mL(-1), we achieved 99.9 and 99.8% inactivation of Mycobacterium kansasii and Mycobacterium avium with rate constant of 6.2 × 10(-3) and 4.2 × 10(-3) min(-1), respectively, after 240 min. We compared the proposed method with the photolytic and photocatalytic methods. Using a mycobacteria population of 7.5 × 10(4) CFU mL(-1), the proposed Ti/TiO2-Ag photoanode elicited total mycobacteria inactivation within 3 min of treatment; the presence of Ag nanoparticles in the electrode provided 1.5 larger degradation rate constant as compared with the Ti/TiO2 anode (1.75 × 10(-2) for M. kansassi and 1.98 × 10(-2) for M. avium). We monitored the degradation of the metabolites released during cellular lysis by TOC removal, sugar release, chromatography, and mass spectrometry measurements; photoelectrocatalysis and Ti/TiO2-Ag photoanodes furnished the best results.

Journal of Chemical Technology & Biotechnology, 2013

BACKGROUND: Rapid-growing mycobacteria are difficult to eradicate using common disinfection pract... more BACKGROUND: Rapid-growing mycobacteria are difficult to eradicate using common disinfection practices, when compared with coliforms. They are resistant to chlorination, which is commonly used in swimming pool and drinking water treatment. They also resist treatment with glutaraldehyde (GA), benzalkonium chloride, organomercury compounds, chlorohexidine, and even autoclavation. So, the present work describes the development of a new treatment method for Mycobacterium disinfection based on phoelectrocatalytical oxidation at Ti/TiO 2 nanotubes electrodes, which could be a promising alternative for its inactivation in a short treatment time. RESULTS: Nanotubular TiO 2 was grown on Ti surface using electrochemical anodization in fluoride medium and applied to photoelectrocatalytic inactivation of 10 3 CFU mL-1 Mycobaterium fortuitum, M. chelonae, and M. abscessus, which was achieved after 3 min treatment. The metabolites released during cellular lysis were also degraded with 240 min of photoelectrocatalytical treatment, as monitored by mass spectroscopy measurements. Mineralization was greater than 70% under optimum conditions. The photoelectrocatalytic method gave better results than the photolytic and photocatalytic techniques. The method provided the most efficient mycobacterial inactivation and TOC removal rate, thus being the best to disinfect mycobacterium-infected water. CONCLUSION: Photoelectrodes based on Ti/TiO 2 nanotubes prepared by electrochemical anodization are a powerful alternative to disinfect mycobacterium-contaminated water.

Journal of Chemical Technology & Biotechnology, 2013

BACKGROUND: Rapid-growing mycobacteria are difficult to eradicate using common disinfection pract... more BACKGROUND: Rapid-growing mycobacteria are difficult to eradicate using common disinfection practices, when compared with coliforms. They are resistant to chlorination, which is commonly used in swimming pool and drinking water treatment. They also resist treatment with glutaraldehyde (GA), benzalkonium chloride, organomercury compounds, chlorohexidine, and even autoclavation. So, the present work describes the development of a new treatment method for Mycobacterium disinfection based on phoelectrocatalytical oxidation at Ti/TiO 2 nanotubes electrodes, which could be a promising alternative for its inactivation in a short treatment time. RESULTS: Nanotubular TiO 2 was grown on Ti surface using electrochemical anodization in fluoride medium and applied to photoelectrocatalytic inactivation of 10 3 CFU mL-1 Mycobaterium fortuitum, M. chelonae, and M. abscessus, which was achieved after 3 min treatment. The metabolites released during cellular lysis were also degraded with 240 min of photoelectrocatalytical treatment, as monitored by mass spectroscopy measurements. Mineralization was greater than 70% under optimum conditions. The photoelectrocatalytic method gave better results than the photolytic and photocatalytic techniques. The method provided the most efficient mycobacterial inactivation and TOC removal rate, thus being the best to disinfect mycobacterium-infected water. CONCLUSION: Photoelectrodes based on Ti/TiO 2 nanotubes prepared by electrochemical anodization are a powerful alternative to disinfect mycobacterium-contaminated water.

Electrochimica Acta, 2012

ABSTRACT TiO2 nanotubular array electrodes coated with 16% (w/w) Ag nanoparticles (Ti/TiO2-Ag) ha... more ABSTRACT TiO2 nanotubular array electrodes coated with 16% (w/w) Ag nanoparticles (Ti/TiO2-Ag) have shown excellent performance in the disinfection of water containing Mycobacterium smegmatis. Photoelectrocatalytic disinfection of M. smegmatis 5.1 × 103 Colony Forming Units (CFU) mL−1 in 0.05 M Na2SO4 (pH 6), applied potential of +1.5 V versus Ag/AgCl and UV irradiation promoted 100% inactivation after 3 min of treatment. Mycobacteria degradation was also monitored by TOC removal, sugar release, chromatography and mass spectroscopy measurements. All analytical methods used confirmed that there was complete inactivation of mycobacteria and degradation of the by-products generated during cellular lyses by the proposed method.

Chemosphere, 2010

Photoelectrocatalytic oxidation of 0.1mM of Bisphenol A (BPA) leads to 100% of degradation monito... more Photoelectrocatalytic oxidation of 0.1mM of Bisphenol A (BPA) leads to 100% of degradation monitored by liquid chromatography with diode array optical detection (limit 1microgL(-1)) and 100% TOC removal. Optimum performance was obtained using TiO(2) nanotubular array (NTA) electrodes, grown by anodization of Ti foil in 0.25wt.% NH(4)F and a mixture of glycerol and water (ratio 90:10vol.%) using an applied voltage of 20V for 50h. The effects of supporting electrolyte, pH, applied bias potential and BPA concentration were evaluated as to their effect on the BPA degradation kinetics and the best condition was found to be 0.1M Na(2)SO(4) at pH 6 as supporting electrolyte and applied bias potential of +1.5V vs. Ag/AgCl under UV irradiation. Our findings indicate that TiO(2) NTAs prepared by anodization are versatile and efficient photocatalysts for the degradation of endocrine disruptors.

... Um pico bem definido em + 0,57 V é observado, o qual é atribuído à oxidação do grupo amina da... more ... Um pico bem definido em + 0,57 V é observado, o qual é atribuído à oxidação do grupo amina da hidrazona formada e imobilizada no eletrodo, após reação direta entre os grupos carboxílicos do poli aminoácido eo grupo amina da hidrazina. ... [10] A. Salimi, K. Abdi, Talanta 63 ...

Talanta, 2016

This paper addresses a sensitive method for the detection of mycobacteria in hemodialysis water s... more This paper addresses a sensitive method for the detection of mycobacteria in hemodialysis water samples based on a magneto-actuated immunoassay with optical readout. In this approach, micro (2.8 μm) sized magnetic particles were modified with an antibody against the lipoarabinomannan (LAM) located in the mycobacterial cell wall. The system relies on the immunocapturing of the mycobacteria with the tailored antiLAM magnetic particles to pre-concentrate the bacteria from the hemodialysis samples throughout an immunological reaction. The performance of the immunomagnetic separation on the magnetic carrier was evaluated using confocal microscopy to study the binding pattern, as well as a magneto-actuated immunoassay with optical readout for the rapid detection of the bacteria in spiked hemodialysis samples. In this approach, the antiLAM polyclonal antibody was labeled with fluorescein isothiocyanate. The optical readout was achieved by the incubation with a secondary anti-fluorescein antibody labeled with peroxidase as optical reporter. The magneto-actuated immunoassay was able to detect mycobacteria contamination in hemodialysis water at a limit of detection of 13 CFU mL À 1 in a total assay time of 3 h without any previous culturing pre-enrichment step.

Applied Catalysis A: General, 2016

Photoelectrocatalysis (PEC) has become an attractive technology to disinfect microorganisms from ... more Photoelectrocatalysis (PEC) has become an attractive technology to disinfect microorganisms from aqueous environments because of its ability to degrade microorganisms without producing any harmful by-products. PEC methodology was applied to inactivate Candida parapsilosis sensu stricto in planktonic and biofilm cells, and its efficiency was compared to that of photolytic and photocatalytic treatment. In the case of planktonic (free-floating) cells, PEC promoted the inactivation of 10 6 CFU mL −1 after 3 min of treatment, and the addition of silver nanoparticles to the Ti/TiO 2 electrodes had virtually no effect on the disinfection period, although it caused a decrease by a factor of 1.5 in the mineralization efficiency. After 60, 10 and 60 min of treatment, PEC methodology reduced 10 6 CFU mL −1 on fungal biofilms and provided 71, 91 and 92% mineralization for biofilm cells performed on polyvinyl chloride (PVC), silicone, and polytetrafluoroethylene (PTFE), respectively. These results indicated that PEC is a promising process for disinfection of water contaminated with C. parapsilosis sensu stricto in both planktonic and biofilm cells.