RESUMO
The catalytic activity of Mn2O3, FeOOH and CeO2 nanoparticles was evaluated in the treatment of a synthetic petroleum refinery wastewater (SPRW) using O3 in a discontinuous reactor at 25°C and pH 5.5. The mineralization and partial chemical oxidation rates of SPRW using these metal oxides are in the same order of magnitude, and the catalytic activity in the mineralization of SPRW decreased in the order Mn2O3 > CeO2 > FeOOH. The mineralized fraction progressively increased with time in the catalytic process while in the non-catalytic process it remained constant. The effect of the operational conditions on the mineralization and partial chemical oxidation rates using Mn2O3 was investigated in detail. The mineralization rate was found to be lower than the partial oxidation rate due to the formation of partially oxidized by-products, and this is dependent on the solids dosage and pH. An investigation of the mechanism demonstrated that the enhancement effect could be attributed to the introduction of the manganese oxide nanoparticles, which could promote the utilization of O3 and/or enhance the formation of free radicals (â¢OH, â¢O2H and â¢O2-) on the solid surface and further accelerate the degradation of the organic compounds present in the wastewater.
Assuntos
Ozônio , Petróleo , Poluentes Químicos da Água , Catálise , Oxirredução , Óxidos , Águas ResiduáriasRESUMO
This study aimed at evaluating the levels of moisture, protein, water to protein ratio, and water absorption during chilling of chicken giblets (heart, liver, and gizzard) to set legal limits of water absorption during this process. The survey was conducted in the southern Brazil, the largest broiler-producing region of this country. Giblets (heart, liver, and gizzard) were collected fresh from the processing line after evisceration and at the exit of the chiller after the immersion process from two processing plants. One of the plants (PP1) processes small chickens (1,100g live weight) and PP2 processes chickens with 2,800g live weight. In total, 448 samples were collected. Laboratory tests were performed in duplicate for each parameter measured. The results show that moisture levels of fresh giblets were higher in the gizzard, followed by the liver and the heart, whereas in chilled giblets, the gizzard still maintained the highest moisture level, but was followed by the heart and then the liver. Both in fresh and chilled samples, the liver presented the highest protein content, followed by the gizzard and the heart. Water to protein ratios were higher in chilled than in fresh samples, and was highest in the heart, followed by the gizzard and the liver. After immersion in the chiller, the heart presented the highest water absorption rate (6.59%), which was significantly higher compared with those of the liver (4.16%) and the gizzard (4.51%). Considering that the water absorption rates obtained both in fresh and chilled chicken giblets were below 8.00%, the following upper limits of water absorption are suggested for chicken giblet processing in Brazil: 7.0% for the heart, and 5.0% for the gizzard and the liver.
Assuntos
Animais , Galinhas/fisiologia , Galinhas/metabolismo , Ingestão de Líquidos/fisiologia , UmidadeRESUMO
This study aimed at evaluating the levels of moisture, protein, water to protein ratio, and water absorption during chilling of chicken giblets (heart, liver, and gizzard) to set legal limits of water absorption during this process. The survey was conducted in the southern Brazil, the largest broiler-producing region of this country. Giblets (heart, liver, and gizzard) were collected fresh from the processing line after evisceration and at the exit of the chiller after the immersion process from two processing plants. One of the plants (PP1) processes small chickens (1,100g live weight) and PP2 processes chickens with 2,800g live weight. In total, 448 samples were collected. Laboratory tests were performed in duplicate for each parameter measured. The results show that moisture levels of fresh giblets were higher in the gizzard, followed by the liver and the heart, whereas in chilled giblets, the gizzard still maintained the highest moisture level, but was followed by the heart and then the liver. Both in fresh and chilled samples, the liver presented the highest protein content, followed by the gizzard and the heart. Water to protein ratios were higher in chilled than in fresh samples, and was highest in the heart, followed by the gizzard and the liver. After immersion in the chiller, the heart presented the highest water absorption rate (6.59%), which was significantly higher compared with those of the liver (4.16%) and the gizzard (4.51%). Considering that the water absorption rates obtained both in fresh and chilled chicken giblets were below 8.00%, the following upper limits of water absorption are suggested for chicken giblet processing in Brazil: 7.0% for the heart, and 5.0% for the gizzard and the liver.(AU)