Fenton Redox Chemistry: Arsenite Oxidation by Metallic Surfaces

Pre-oxidation of As(III) is necessary in arsenic removal processes in order to increase its efficiency. Therefore, the Fenton Redox Chemistry is defined by catalytic activation of H2O2 and currently common used for its redox oxidative properties. In this study the effect of H2O2 production catalysed by O2 in metallic surfaces (MS), such as metallic Cu/Zn alloys and Composite Iron Matrix (CIM), for As(III) oxidation is under investigation. Preliminary results show that As(III) is partly oxidized only by the presence of O2 without addition of MS. However, with delayed addition of MS, As(III) oxidation occurred but only due to ROS catalyzed by the metallic surfaces.Water ManagementCivil Engineering and Geoscience

Aspectos microbiológicos e físico-químicos da parte interna da paleta suína curada, maturada e fermentada durante a etapa de processamento e armazenamento Microbiological and physical chemical aspects in the internal parts pig palette cured, matured and fermented during processing and storage

Utilizou-se como matéria-prima a paleta suína e elaborou-se um produto cárneo similar ao presunto curado espanhol. Acompanhou-se a evolução de alguns parâmetros físico-químicos (pH, a w, NO2, umidade, cloretos) e microbiológicos (bactérias mesófilos, lácticas, Micrococcacea, Staphylococcus xylosus), na parte interna da paleta suína, e relacionou-os com as ações que os mesmos exercem nos produtos cárneos fermentados e curados, nas diferentes fases de processamento e armazenamento, tendo em vista que o produto elaborado com a paleta suína é similar a esses produtos cárneos. Os resultados mostraram que as concentrações de cloretos do quinto ponto de coleta (20&deg; dia) em diante apresentaram ação bacteriostática frente às bactérias que alteram o produto, e que os valores de a w menores do que 0,93 e de umidade inferiores a 64%, durante o período de armazenamento, agiram como obstáculos frente ao desenvolvimento das bactérias da família Enterobacteriaceae. Representantes da família Microccocaceae e do grupo das bactérias ácido lácticas desenvolveram-se em baixos valores de a w e em alta concentração de cloreto.<br>Pig palette was used as ra w material, and a meat product similar to the Spanish cured ham was produced. Some physical and chemical parameters (pH, a w, NO2, moisture and sodium chloride), as well as microbiological countings (mesophilic bacteria, lactic acid bacteria, Micrococcaceae, Staphylococcus xylosus) were assessed in the internal part pig palette, during the steps of processing and storage. These parameters were correlated with the actions that they exert in fermented and cured meat products. The results showed that the concentration of sodium chloride after the 20th day presented bacteriostatic action on the bacteria that modify the product. The values of a w lower than 0.93 and moisture lower than 64%, during the storage period, acted as obstacles to the development of bacteria of the Entreobacteriaceae family. Representatives of the Microccocaceae family and of the lactic acid bacteria grew at low a w and at high concentration of sodium chloride