Performance assessment of micropollutants removal from water using advanced oxidation processes

In a global climate change scenario, reliable access to clean and safe water for all remains a great worldwide challenge for the twenty first century, as one of the most ambitious targets of several Sustainable Development Goals (SDG) established in the UN Agenda 2030. The increasing presence in the urban aquatic ecosystems of priority pollutants and contaminants of emerging concerning (CECs) have brought new challenges to the existing water treatment systems (WTS) concerning with public health protection and the of drinking water sources preservation. Advanced oxidation processes (AOPs) have been widely studied because of their potential as a complementary or alternative process to conventional wastewater treatment. Several AOPs using nanomaterials as photocatalyst can be particularly effective in the degradation of many toxic micropollutants, and enhance the multifunctionality, versatility and sustainability of WTS. This work presents a synthesis of the major results obtained in several pilot and lab-scale studies aiming to assess the performance of different low-cost catalytic processes used for antibiotic and pesticide removal. For each photo-oxidation reactors, different test scenarios are defined in order to evaluate the effects of several abiotic and hydraulic parameters on process kinetics and removal efficiencies. The experimental results were very promising, because antibiotic removal efficiencies achieved the maximum value of 96% for the photo-oxidation by water columns with suspended TiO2 nanoparticles, and 98% for the photocatalytic filtration performed by a porous medium coated with TiO2. In the photoelectrocatalytic reactor, the atrazine concentration has been fully removed for reaction times between 35 and 95 minutes.(undefined

Microstructure and paramagnetic Meissner effect of YBa2Cu3Oy nanowire networks

The microstructure and magnetic characterizations of non-woven, fabric-like YBa2Cu3Oy (YBCO) nanofiber mats are reported. The samples were produced by solution blow spinning (SBS), starting from a sol-gel solution of the precursor materials in polyvinylpyrrolidone. In the present work, the nanowire network samples were morphologically characterized by scanning electron microscopy, and the superconducting properties were measured by magnetometry. An interesting feature is the appearance of a paramagnetic Meissner effect (PME) when field-cooling, firstly verified in that sort of sample. The PME appears only in very small applied magnetic fields, which is similar to previous observations of the PME on an artificially granular YBCO thin film, but distinctly different from bulk samples investigated in the literature. Thus, we explain the PME by flux trapping within the voids of the nanoporous structure of the nanofiber mats

Comportamento Térmico da Fibra do Açaí.

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Lixiviação de atrazina em solo em área de recarga do Aquífero Guarani.

No Aqüífero Guarani, o maior e mais importante lençol de água subterrânea de toda a região centro-sul do país, encontra-se a microbacia do Córrego do Espraiado, um dos seus pontos de recarga. Nesta área, existe predomínio de culturas, nas quais são utilizados herbicidas da família das triazinas e a presença de solo arenoso, que tornam a área vulnerável à lixiviação. Entre os produtos aplicados encontra-se a atrazina (2-chloro-4-(ethylamino)-6-(isopropylamino)-S-triazine). Devido as suas características físico-químicas, esse herbicida tem alto potencial de risco de movimentar-se para água subterrânea. Para avaliar a lixiviação da atrazina foram feitas amostragens de solo para análise física e de água superficial e subterrânea, durante os anos de 2000 a 2002, para análise de resíduo através de cromatografia líquida HPLC (High Performance Liquid Chromatography), e confirmadas com GC-MS (Gas chromatography-mass spectrometry). Apenas quatro amostras de água superficial apresentaram resíduos de atrazina. Destas, duas com 0,04; e as outras com 0,05 e 0,09 ug/L. Nas amostras de água subterrânea os resultados indicaram uma amostra contendo 0,03 ug/L de atrazina. Entretanto, nenhuma delas foi confirmada pelo GC-MS, não indicando resíduos. A presente avaliação contou também com o uso do simulador de sistemas CMLS-94 (Chemical Movement in Layered Soils). O simulador também mostrou que a atrazina não atinge profundidades comprometedoras para a qualidade do aquífero

Arsenic removal from drinking water by advanced filtration processes

All over the world the presence of arsenic in water sources for human consumption has been raising great concern in terms of public health since many epidemiologic studies confirm the potential carcinogenic effect of arsenic. Because arsenic removal is the most frequent option for safe drinking water, the development of more efficient and sustainable technologies is extremely important. Membrane separation processes are suitable for water treatment because they can provide an absolute barrier for bacteria and viruses, besides removing turbidity and colour. Their application is a promising technology in arsenic removal since it does not require the addition of chemical reagents nor the preliminary oxidation of arsenite required in conventional treatment options. However, since membrane technologies such as reverse osmosis can be a very expensive and unsustainable treatment option for small water supply systems, it becomes crucial that alternative methods are developed. This work presents a few conclusions based on a laboratorial study performed to evaluate the efficiency of arsenic removal using ultrafiltration, microfiltration and solar oxidation processes under different experimental conditions for relevant parameters. The results showed removal efficiencies higher than 90%

Manual do usuário do programa AGROSCRE: apoio à avaliação de tendências de transporte de princípios ativos de agrotóxicos.

O programa AGROSCRE foi elaborado para conferir agilidade da avaliação de modelos matemáticos screening, que auxiliam a análise do potencial de contaminação de agrotóxicos em água. Este trabalho apresenta o manual do usuário deste programa, possibilitando uma maior divulgação do uso dos modelos ?screening? e fomentando avaliações, cada vez mais fidedignas, da realidade local do ambiente de produção agrícola nacional, na medida em que os dados de entrada forem refinados. Foi desenvolvido em linguagem Quick Basic 4.5 e necessita de 11K de memória para ser utilizado em modo executável.bitstream/item/204159/1/Manual-Agroscre-Pessoa-2007.pdf; bitstream/item/103181/1/Doc-61-Agroscre.zipEndereço para baixar o programa AGROSCRE: http://www.cnpma.embrapa.br/forms/agroscre.php

Avaliação do potencial de transporte de agrotóxicos usados no Brasil por modelos Screening e planilha eletrônica.

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