Showing papers by "Mônica Maria Diniz Leão published in 2009"
TL;DR: In this paper, the authors compare the processos de oxidacao avancada (H2O2, UV, UV/H2 O2, Fe2+/H 2 O2, UV/Fe2+ O2+, H2O 2 O 2, Fe2 O 2 + O 2 ) for degradacao do corante textil Reactive Red 195, and show that the use of a siderurgico aumentou a velocidade de descoloracao.
Abstract: O objetivo deste estudo foi comparar os processos de oxidacao avancada (H2O2, UV, UV/H2O2, Fe2+/H2O2, UV/Fe2+/H2O2) para descoloracao do corante textil Reactive Red 195. Tambem foi investigada a utilizacao do po do desempoeiramento da ala de corrida do alto forno como fonte alternativa de ferro na peroxidacao catalitica, com e sem radiacao UV, para degradacao do corante. O efeito das concentracoes de H2O2 e corante na cinetica de descoloracao foram estudados. Os resultados indicaram que a maior eficiencia de descoloracao foi obtida atraves do sistema foto-Fenton com o uso do residuo; entretanto, a utilizacao do residuo no sistema Fenton sem irradiacao atingiu a mesma eficiencia, com tempo de reacao aumentado em apenas 15 minutos. A utilizacao do residuo siderurgico aumentou a velocidade de descoloracao, mostrando-se bastante promissora como fonte de ferro.
22 citations
TL;DR: In this paper, the textile effluent biodegradability, both before and after its treatment with Fenton's Reagent, were compared by means of biologic tests, and it was shown that the Fenton treatment lowered the bioregradabilty of practically all tested effluents, except one specific effluent from a scouring bath of polyester fibers, which achieved a 93% COD removal.
Abstract: From the environmental point of view, the textile sector is outstanding for the generation of large amounts of biorecalcitrant effluents. In this paper the textile effluent biodegradability, both before and after its treatment with Fenton's Reagent, were compared by means of biologic tests. These tests showed that the Fenton treatment lowered the biodegradabilty of practically all tested effluents, except one specific effluent from a scouring bath of polyester fibers, which achieved a 93% COD removal. This removal was due to a significant phase separation (oil/water).
5 citations
TL;DR: Evaluated time trends of concentration of arsenic in water courses of the basin of das Velhas River, considering the data of twenty-nine monitoring stations from 1998 to 2007, found that seasonality, autocorrelation and temporal trend were virtually nonexistent.
Abstract: Arsenic, a metalloid with wide distribution in nature, can be found in natural environments in the forms of high toxicity. Monitoring conducted in the Basin of the das Velhas River, MG, demonstrates the occurrence of this metal in all sampling stations distributed over the water course and main tributaries. Thus, this study aims to evaluate the time trends of concentration of arsenic in water courses of the basin of das Velhas River, considering the data of twenty-nine monitoring stations from 1998 to 2007. The tests included the verification of seasonality, autocorrelation and temporal trend with the non-parametric tests of Mann-Kendall and Mann-Kendall seasonal. Eight sampling stations showed seasonality, with higher concentrations observed in rainy season. The autocorrelation was virtually nonexistent, which may be associated with low sample found in a monitoring program (three to six months). Only seven monitoring stations showed significant negative
4 citations
TL;DR: In this article, spatial patterns of water quality at 29 sites, in a mixed land use watershed located in southeastern Brazil, were examined for eight metals, sampled over nine years -Arsenic, Cadmium, Copper, Lead, Mercury, Nickel, Selenium, and Zinc.
Abstract: Spatial patterns of water quality at 29 sites, in a mixed land use watershed located in southeastern Brazil, were examined for eight metals, sampled over nine years -Arsenic, Cadmium, Copper, Lead, Mercury, Nickel, Selenium, and Zinc. Data analysis included delineation of the area of influence of each monitoring station, based on GIS analysis of Shuttle Radar Topography Mission (SRTM) images, estimation of the upper prediction limit 95% (UPL95) with censored data by the Kaplan-Meier technique, hierarchical cluster analysis (CA), Kruskal-Wallis and Friedman test. The locations of the groups generated by CA agreed with land and soil use and impact of anthropogenic activities. Use of UPL95 as entry data in CA allowed better use and interpretation of monitoring data. Areas with natural background metal-concentration levels in the drainage basin and areas of concern were identified.
2 citations
TL;DR: Os resultados demonstraram that os estudos de tendencia temporal apresentam grande relevância para a gestao da poluicao dos recursos hidricos a partir of dados de monitoramento, fornecendo subsidios para medidas preventivas e corretivas diferenciadas entre as estacoes de amostragem e periodos do ano.
Abstract: O arsenio e um metaloide com ampla distribuicao na natureza, podendo ser encontrado nos ambientes naturais em formas de elevada toxicidade. Monitoramentos realizados na Bacia do Rio das Velhas, MG, demonstram a ocorrencia desse metal em todas as estacoes de amostragem distribuidas ao longo de seu curso d'agua principal e afluentes. Assim, o presente estudo objetiva avaliar as tendencias temporais da concentracao de arsenio nos cursos d'agua da bacia do Rio das Velhas, considerando os dados das vinte e nove estacoes de monitoramento obtidos de 1998 a 2007. As analises incluiram a verificacao da sazonalidade, autocorrelacao e testes de tendencia temporal nao-parametricos de Mann-Kendall e Mann-Kendall Sazonal. Oito estacoes de amostragem apresentaram sazonalidade, com as maiores concentracoes verificadas no periodo chuvoso. A autocorrelacao foi praticamente inexistente, o que pode estar associado a baixa frequencia amostral verificada no programa de monitoramento (tres a seis meses). Apenas sete estacoes apresentaram tendencia negativa significativa, indicando uma reducao na concentracao de arsenio ao longo do periodo estudado. Os resultados demonstraram que os estudos de tendencia temporal apresentam grande relevância para a gestao da poluicao dos recursos hidricos a partir de dados de monitoramento, fornecendo subsidios para medidas preventivas e corretivas diferenciadas entre as estacoes de amostragem e periodos do ano, podendo ainda ser utilizado na avaliacao da efetividade dessas medidas.