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The purpose of this research was to evaluate the apparent molecular weight distribution of dissolved organic matter (DOM) from pig slurry and the binding ability of its fractions toward copper (Cu2+) ions. In addition, the binding ability (maximum complexing capacity – MCC) of the DOM was compared with that of humic (HA) and fulvic (FA) acids from a clay-loam soil. The study was performed using Cu2+ ions since this metal is widely used as a supplement in pig diets and, consequently, is present in pig slurry. The techniques adopted were gel filtration chromatography (GFC) and dialysis. GFC showed that the DOM from pig slurry is mainly composed of a fraction with an apparent molecular weight higher than 5000 Da and the copper naturally present in the slurry is completely complexed by this fraction. The dialysis procedure enabled MCC to be determined. The MCC of pig slurry DOM and soil HA, which contained a similar concentration of carboxylic groups, were analogous, while MCC of soil FA, which contained double the concentration of carboxylic groups, was higher. 相似文献
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Zapatero Osorio MR Béjar VJ Martín EL Rebolo R Barrado y Navascués D Bailer-Jones CA Mundt R 《Science (New York, N.Y.)》2000,290(5489):103-107
We present the discovery by optical and near-infrared imaging of an extremely red, low-luminosity population of isolated objects in the young, nearby stellar cluster around the multiple, massive star final sigma Orionis. The proximity (352 parsecs), youth (1 million to 5 million years), and low internal extinction make this cluster an ideal site to explore the substellar domain from the hydrogen mass limit down to a few Jupiter masses. Optical and near-infrared low-resolution spectroscopy of three of these objects confirms the very cool spectral energy distribution (atmospheric effective temperatures of 1700 to 2200 kelvin) expected for cluster members with masses in the range 5 to 15 times that of Jupiter. Like the planets of the solar system, these objects are unable to sustain stable nuclear burning in their interiors, but in contrast they are not bound to stars. This new kind of isolated giant planet, which apparently forms on time scales of less than a few million years, offers a challenge to our understanding of the formation processes of planetary mass objects. 相似文献
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Tesedo J Barrado E Sanz MA Tesedo A de la Rosa F 《Journal of agricultural and food chemistry》2006,54(17):6255-6260
The fatty acid compositions of egg yolks subjected to industrial processing treatments, namely, homogenization, pasteurization, drying, and "omega-3-enrichment", were studied. In general, the total contents of C16:0, C18:0, C18:1 n-9, and C18:2 n-6 fatty acids accounted for close to 90% of the total fatty acids. Statistical analysis of the data revealed correlations among the fatty acids; significant differences existed depending on the egg source and type of processing. Yolk samples enriched with omega-3 fatty acids clustered together owing to their higher C16:0, C16:1 n-7, C18:3 n-6, and C24:0 contents. Nonpasteurized/non-heat-treated samples formed another cluster because of their higher C18:1 n-11 and C18:1 n-9 contents, and the remaining samples formed another group due to their higher proportions of C18:0, C18:2 n-6, and C20:4 n-6. The relative proportions of essential fatty acids were similar in the four types of samples examined. 相似文献
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Helena Beatriz A. Vega Marisol Barrado Enrique Pardo Rafael Fernández Luis 《Water, air, and soil pollution》1999,112(3-4):365-387
21 physico-chemical parameters have been determined in 47 groundwater samples collected in October 1994 from the alluvial aquifer of the Pisuerga river, located at the north-east of Valladolid (north-western Spain). Conventional hydrochemical methods and multivariate statistical analysis have been used to discriminate natural phenomena and pollution processes in the area. It has been demonstrated the existence of a heterogeneity in groundwater mineral contents related to anthropic actions such as irrigation, source of irrigation water and location of polluting sources. This study demonstrates the existence of two sub-units in the alluvial aquifer (left and right river banks) with different hydrochemical characteristics, and identifies three different singular areas in the left bank. Groundwater from this bank showed higher levels of dissolved ions caused by concentration processes derived from the predominant use of groundwater for crop irrigation, whilst in the right bank of the aquifer less saline water from canals is used. Degradation of groundwater quality has been observed in some areas of the left aquifer sub-unit (north, Santovenia and south-central sites) where anomalous high concentrations of sulphate, sodium, chloride and nitrate were measured, and can be related to the presence of potentially polluting sources such as leachates from industrial waste disposals, sewage effluents and use of organic and inorganic fertilizers. 相似文献
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Barrado E. Prieto F. Lozano B. Arenas F. J. Medina J. 《Water, air, and soil pollution》2001,131(1-4):367-381
Waste water polluted with heavy metals can besuccessfully purified by precipitation of the metals from analkaline solution containing iron (II), giving rise to aferrite sludge. The solid metal ferrites obtained in thismanner can be used to remove hydrogen sulphide from a gasstream. Based on a Taguchi experimental design, ferrite solidparticle and pore size, and the temperature resulting inmaximum retention of H2S by the solid were optimised.Under the optimum conditions, predicted by the method, eachgram of ferrite was able to retain 0.274 g H2S.In addition, a ferrite containing a known lead concentration,obtained by the precipitation method under optimal conditionsof pH, temperature and Fe/Pb ratio, was used to study theexothermic H2S retention reaction. The chemical reactionoccurring between the ferrite and the H2S wasinvestigated by characterisation of the compounds before(Pb0.04FeII 0.96 FeIII 2O4·nH2O solids composed ofPbxFe3-xO4, magnetite Fe3O4 andhydrated lead oxide PbOn·H2O) and after (PbS, PbSO4, S, FeS2 and α-FeO(OH)) the retention process. 相似文献
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