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Search Results: 1 - 10 of 402182 matches for " Márcia M. Kondo "
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Imobiliza??o de TiO2 em concreto: fotodegrada??o de clorofórmio e fenol
Santos, Valquíria Claret dos;Kondo, Márcia Matiko;
Química Nova , 2006, DOI: 10.1590/S0100-40422006000200015
Abstract: tio2 immobilization on concrete was studied using mixtures with cement, varnish and resin. the uv radiation sources were a germicide uv lamp and solar light. aqueous solutions of chloroform (chcl3) and of phenol were prepared and recirculated over the tio2 immobilized surfaces. the immobilized tio2 surfaces showed better photocatalytic efficiency for phenol degradation compared to the control. for chcl3, the presence or absence of the catalyst did not cause any significant difference to its degradation efficiency. the micrographic results showed a more homogeneous surface for tio2 immobilized in resin and varnish.
Imobiliza o de TiO2 em concreto: fotodegrada o de clorofórmio e fenol
Santos Valquíria Claret dos,Kondo Márcia Matiko
Química Nova , 2006,
Abstract: TiO2 immobilization on concrete was studied using mixtures with cement, varnish and resin. The UV radiation sources were a germicide UV lamp and solar light. Aqueous solutions of chloroform (CHCl3) and of phenol were prepared and recirculated over the TiO2 immobilized surfaces. The immobilized TiO2 surfaces showed better photocatalytic efficiency for phenol degradation compared to the control. For CHCl3, the presence or absence of the catalyst did not cause any significant difference to its degradation efficiency. The micrographic results showed a more homogeneous surface for TiO2 immobilized in resin and varnish.
Photocatalytic Degradation of Ibuprofen Using TiO2 and Ecotoxicological Assessment of Degradation Intermediates against Daphnia similis  [PDF]
Farley S. Braz, Milady R. A. Silva, Flávio S. Silva, Sandro J. Andrade, Ana L. Fonseca, Márcia M. Kondo
Journal of Environmental Protection (JEP) , 2014, DOI: 10.4236/jep.2014.57063
Abstract:

Several pharmaceutical compounds have been detected in natural aqueous systems and ibuprofen (IBF), one of the most consumed medicament, has been detected in many countries. The degradation efficiency of IBF under TiO2/UV radiation was evaluated. Optimum degradation results were observed using 20 mg·L-1 of TiO2, pH 7.8 and 5 mg·L-1 of IBF. Under these experimental conditions total IBF removal was achieved in less than 60 min of irradiation. Although total IBF concentration was observed, the total mineralization of the compound was not achieved. The by-products generated during TiO2/UV reaction showed to be more toxic against Daphnia similis than the initial IBF present in aqueous solution.

TiO2/CuO Films Obtained by Citrate Precursor Method for Photocatalytic Application  [PDF]
Leinig Perazolli, Luciana Nu?ez, Milady Renata Apolinário da Silva, Guilherme Francisco Pegler, Ademir Geraldo Cavalarri Costalonga, Rossano Gimenes, Márcia Matiko Kondo, Maria Aparecida Zaghete Bertochi
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.26075
Abstract: In the present work, the hybrid catalyst films of TiO2/CuO containing up to 10% in mol of copper were deposited onto glass surface. Precursor solutions were obtained by citrate precursor method. Films were porous and the average particle size was 20 nm determined by FEG-SEM analysis. The photocatalytic activities of these films were studied using Rhodamine B as a target compound in a fixed bed reactor developed in our laboratory and UV lamp. It was observed that the addition of copper to TiO2 increased significantly its photocatalytic activity during the oxidation of Rhodamine B. The degradation exceeded 90% within 48 hours of irradiation compared to 38% when pure TiO2 was used. Moreover, there was a reduction in the particles band gap energy when compared to that of pure TiO2. These results indicate that the TiO2/CuO films are promising catalysts for the development of fixed bed reactors to be used to treat effluents containing azo dyes.
Dissolved Organic Carbon Determination Using FIA and Photo-Fenton Reaction
Kondo, Márcia M.;Arcos, Maria A. S. V.;Grassi, Marco T.;
Brazilian Archives of Biology and Technology , 2002, DOI: 10.1590/S1516-89132002000100013
Abstract: the fia-photo-fenton system is based on the flow oxidation of the organic matter. a small amount of the sample containing h2o2 is injected into the acidic flow solution of fe2+, which passes through a tubular ptfe reactor irradiated with uv light. the generated co2 is quantified by a conductometric detector and is directly proportional to the dissolved organic carbon concentration in the sample. the optimization studies were performed using edta solutions. the average recovery of organic carbon was 83% with a relative standard deviation of 3.7% using a 1:5 molar ratio of fe2+:h2o2, ph 2.0, 100 ml of sample injection and a liquid flow of 1 ml min-1. after optimization, the doc concentration was quantified using 13 different organic compounds, where the average recovery was 90%. the rate of the analysis was in average 50 samples hour-1.
Dissolved Organic Carbon Determination Using FIA and Photo-Fenton Reaction
Kondo Márcia M.,Arcos Maria A. S. V.,Grassi Marco T.
Brazilian Archives of Biology and Technology , 2002,
Abstract: The FIA-photo-Fenton system is based on the flow oxidation of the organic matter. A small amount of the sample containing H2O2 is injected into the acidic flow solution of Fe2+, which passes through a tubular PTFE reactor irradiated with UV light. The generated CO2 is quantified by a conductometric detector and is directly proportional to the dissolved organic carbon concentration in the sample. The optimization studies were performed using EDTA solutions. The average recovery of organic carbon was 83% with a relative standard deviation of 3.7% using a 1:5 molar ratio of Fe2+:H2O2, pH 2.0, 100 muL of sample injection and a liquid flow of 1 mL min-1. After optimization, the DOC concentration was quantified using 13 different organic compounds, where the average recovery was 90%. The rate of the analysis was in average 50 samples hour-1.
Impacto do uso de cereal adicionado de ferro sobre os níveis de hemoglobina e a antropometria de pré-escolares
Vítolo, Márcia Regina;Aguirre, Andrea Nogueira de Campos;Kondo, Márcia Regina;Giuliano, Yara;Ferreira, Neil;Lopez, Fábio Ancona;
Revista de Nutri??o , 1998, DOI: 10.1590/S1415-52731998000200007
Abstract: anemia and energetic malnutrition are considered to be the major nutritional challenges in developing countries. the efficacy of the various programs implemented to solve these problems has been assessed by studies with enriched food products. the objective of the present study was to evaluate the daily acceptance of an iron-enriched cereal, as well as its effect on the anthropometric parameters and hemoglobin levels of children aged 1 to 4 years old. fifty-four children enrolled at a public day care unit participated in the study. they were divided into two groups: group i with 24 children (median age: 2 years and 2 months) and group ii with 30 children (median age: 3 years and 6 months). their food intake, weight, height and serum hemoglobin levels were measured at the beginning and at the end of the study. during a period of two months, milk and bread, which made up the children's breakfast and afternoon snack, were substituted by the enriched cereal in the form of porridge, which increased the iron intake in 2 to 3mg per day. the results showed that there was a significant increase in the weight for height rate of both groups, with improvement of nutritional condition in those children with acute malnutrition. with regard to serum hemoglobin levels, group i showed an initial average level of 9.9 ± 2.0g/dl. the average level at the final evaluation, 11.4 ± 1.0g/dl, was significantly higher (p< 0.05) than at the start. group ii, with average serum hemoglobin level of 11.6 ± 0.9g/dl at the start, did not show a significant difference from the level at the end (11.9± 0.9g/dl).at the start of the study the incidence of anemia in group i was of 81%. this value went down to 31.2% at the end of two months. for group ii, the incidence decreased from 20.8% to 12.5% at the end. the average daily intake of cereal during the first week was lower than in subsequent weeks. it is concluded that the product used in this study increased the serum hemoglobin levels of the children
Proposi??o de um reator fotocatalítico para destrui??o de microrganismos em ambientes interiores
Kondo, Márcia Matiko;Orlanda, José Fábio F.;Ferreira, Maria da Glória A. B.;Grassi, Marco Tadeu;
Química Nova , 2003, DOI: 10.1590/S0100-40422003000100022
Abstract: the tio2/uv photocatalytic reactor was investigated as an alternative system to inactivate airborne microorganisms. the experiments performed in the absence of the catalyst showed that direct photolysis was not efficient to destruct microorganisms, with only 30% of inactivation. similar inactivation percentage was obtained using tio2 in absence of uv radiation. the destruction of microorganisms present in a contaminated indoor atmosphere, using the combination of tio2/uv was very efficient, reaching more than 98% of destruction.
Proposi o de um reator fotocatalítico para destrui o de microrganismos em ambientes interiores
Kondo Márcia Matiko,Orlanda José Fábio F.,Ferreira Maria da Glória A. B.,Grassi Marco Tadeu
Química Nova , 2003,
Abstract: The TiO2/UV photocatalytic reactor was investigated as an alternative system to inactivate airborne microorganisms. The experiments performed in the absence of the catalyst showed that direct photolysis was not efficient to destruct microorganisms, with only 30% of inactivation. Similar inactivation percentage was obtained using TiO2 in absence of UV radiation. The destruction of microorganisms present in a contaminated indoor atmosphere, using the combination of TiO2/UV was very efficient, reaching more than 98% of destruction.
Degradation of Abamectin Using the Photo-Fenton Process
Thiago Augusto de Freitas Matos,Alexandra Lemos Nunes Dias,Amanda Di Piazza Reis,Milady Renata Apolinário da Silva,Márcia Matiko Kondo
International Journal of Chemical Engineering , 2012, DOI: 10.1155/2012/915724
Abstract: The cultivation of strawberries generally requires substantial use of pesticides, and abamectin is the active principle of one of those most commonly employed. Conventional water treatment does not remove pesticides efficiently, so there is a need to investigate alternative procedures. The use of advanced oxidation processes (AOPs) can achieve good results in removal of toxic organic compounds present in aqueous solutions. The photo-Fenton process, one example of an AOP, was employed to study the degradation of abamectin. Results showed that when natural water samples contaminated with abamectin were treated using the photo-Fenton process, 70% of the initial amount of the compound was removed within 60 minutes of UV irradiation, and 60% mineralization was observed after 180 minutes of reaction. 1. Introduction Biocides are one of the most important classes of compounds introduced into surface waters by human activities [1]. They are widely used in agriculture and can contaminate rivers and other water bodies due to transport from cultivated areas [2–5]. Although the pesticide industry has developed new compounds that are more effective, even at lower concentrations, and that present lower environmental impacts [6], the misuse of such pesticides can pose considerable toxicity risks to operators, consumers, and the wider environment [7]. The cultivation of strawberries uses large amounts of pesticides. One of the most commonly employed is Vertimec 18 EC, which contains 1.8% (w/v) of abamectin, the active principle. Abamectin belongs to the avermectin group and has the molecular formula C48H72O14 (avermectin B1a) + C47H70O14 (avermectin B1b). It is used primarily as a biocide. Abamectin is a toxic chemical and can be fatal if inhaled, ingested, or absorbed by the skin. It causes skin and eye irritation, and at high doses can cause damage to the central nervous system (CAS no., 71751-41-2). The substance is also highly toxic to fish and aquatic invertebrates. The maximum acceptable daily intake (ADI) is 0.01?mg?kg?1 body weight, and the maximum residue limit is 0.02?mg?kg?1 of the commercial product [8]. Effluents containing biocides cannot usually be treated efficiently using biological techniques, since the effluents are toxic to the microorganisms involved so that the biodegradation efficiency is reduced [9]. An alternative treatment that has been investigated is based on the use of advanced oxidation processes (AOPs), which are very efficient for the removal of potentially toxic organic compounds from water systems. In AOPs, hydroxyl radicals are formed
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