Estudo de parâmetros físicoquímicos para a produção de argamassas utilizando resíduos industriais e da construção civil

As argamassas podem ser consideradas como a mistura de aglomerantes e agregados com água, possuindo capacidade de endurecimento e aderência. Como alternativa, é proposto produção de argamassas utilizando como agregado miúdo resíduos de construção civil (RCC), rico em silicoaluminatos, gerado nas obras de demolições e reformas, e cinza volante (CV) como material pozolânico, obtida a partir da combustão do carvão mineral em caldeiras de leitos fluidizados, em substituição parcial ao cimento Portland. Neste contexto, o resíduo de construção civil foi beneficiado e caracterizado pelas análises de espectrofotometria de raios- X e difração de raios-X, a cinza volante foi caracterizada pela análise granulométrica e espectrofotometria de raios-X. Para produção das argamassas formularam-se composições de RCC nas proporções de 95, 90, 85, 80, 75 e 70%; CV de 0, 5, 10, 15, 20 e 25% e 5% de cimento Portland CP II Z 32, sendo que em cada composição do traço de argamassa foi adicionado 0,8% em volume de água e para o ensaio reológico utilizou-se as mesmas proporções de resíduos (RCC e CV) com 35% em volume de água. Após a cura de 28 dias os corpos de prova foram submetidos a ensaios físicos de absorção, porosidade e massa específica aparente; ensaio mecânico de resistência à compressão e análise de difração de raios-X e microscopia eletrônica de varredura, cujos resultados obtidos mostraram-se ser viável a utilização da cinza volante e RCC na construção civil, na produção de argamassas.

Preliminary risk analysis applied to the handling of health-care waste

Between 75% and 90% of the waste produced by health-care providers no risk or is "general" health-care waste, comparable to domestic waste. The remaining 10-25% of health-care waste is regarded as hazardous due to one or more of the following characteristics: it may contain infectious agents, sharps, toxic or hazardous chemicals or it may be radioactive. Infectious health-care waste, particularly sharps, has been responsible for most of the accidents reported in the literature. In this work the preliminary risks analysis (PRA) technique was used to evaluate practices in the handling of infectious health-care waste. Currently the PRA technique is being used to identify and to evaluate the potential for hazard of the activities, products, and services from facilities and industries. The system studied was a health-care establishment which has handling practices for infectious waste. Thirty-six procedures related to segregation, containment, internal collection, and storage operation were analyzed. The severity of the consequences of the failure (risk) that can occur from careless management of infectious health-care waste was classified into four categories: negligible, marginal, critical, and catastrophic. The results obtained in this study showed that events with critics consequences, about 80%, may occur during the implementation of the containment operation, suggesting the need to prioritize this operation. As a result of the methodology applied in this work, a flowchart the risk series was also obtained. In the flowchart the events that can occur as a consequence of a improper handling of infectious health-care waste, which can cause critical risks such as injuries from sharps and contamination (infection) from pathogenic microorganisms, are shown.

Application of carbon composite adsorbents prepared from coffee waste and clay for the removal of reactive dyes from aqueous solutions

A novel carbon composite was prepared from a mixture of coffee waste and clay with inorganic:organic ratio of 1.3 (CC-1.3). The mixture was pyrolysed at 700 °C. Considering the application of this adsorbent for removal of anionic dyes, the CC-1.3 was treated with a 6 mol L^-1 HCl for 24 h to obtain ACC-1.3. Fourier transform infrared (FTIR), N₂ adsorption/desorption curves, scanning electron microscope (SEM) and powder X-ray diffractometry (XRD) were used for characterisation of CC-1.3 and ACC-1.3 carbon adsorbents. The adsorbents were effectively utilised for removal of reactive blue 19 (RB-19) and reactive violet 5 (RV-5) textile dyes from aqueous solutions. The maximum amounts of RB-19 dye adsorbed at 25 °C are 63.59 (CC-1.3) and 110.6 mg g^-1 (ACC-1.3), and 54.34 (CC-1.3) and 94.32 mg g^-1 (ACC-1.3) for RV-5 dye. Four simulated dye-house effluents were used to test the application of the adsorbents for treatment of effluents.