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E Jurado

Publications and source records attributed to E Jurado.

5 recordsLinked to original sources
PubMed2006

Simplified spectrophotometric method using methylene blue for determining anionic surfactants: applications to the study of primary biodegradation in aerobic screening tests.

In the present work, we propose a simplified spectrophotometric method for determining anionic surfactants, based on the formation of the ionic pair anionic surfactant-methylene blue (AS-MB). This method, in relation to the conventional analytic procedure, considerably reduces not only the quantity of chloroform used in extracting the ionic pair formed, but also the time and the quantity of sample necessary to perform the assay, eliminating the filtration stage. The method has been simplified by displacing the transfer equilibrium of the ionic pair AS-MB towards the organic phase, augmenting the volumetric relationship of chloroform/sample. The method proposed has been applied in the study of primary biodegradation kinetics of linear alkylbenzenesulfonate (LAS).

Alkanesulfonic Acids↗
PubMed2005

Kinetic and enzymatic adsorption model in a recirculation hollow-fibre bioreactor.

A general procedure has been developed to model the behaviour of enzymatic reactions in a membrane bioreactor. This procedure unifies the kinetics of the reaction and the adsorption of the enzyme or enzymatic complexes on the membrane, enabling the selection of the most appropriate kinetic model. The general procedure proposed has been particularized and applied to experimental results obtained with two enzymatic reactions carried out in a hollow-fibre reactor, enzymatic hydrolysis of lactose by beta-galactosidase and glucose-fructose isomerization by glucose isomerase. The application of the general model has allowed us to determine the mechanism of the reaction for both kinetic reactions, assuming the adsorption of the enzymatic complex EGa for lactose hydrolysis and the adsorption of the free enzyme onto the membrane for glucose-fructose isomerization.

Adsorption↗
PubMed2005

The maximum reservoir capacity of soils for persistent organic pollutants: implications for global cycling.

The concept of maximum reservoir capacity (MRC), the ratio of the capacities of the surface soil and of the atmospheric mixed layer (AML) to hold chemical under equilibrium conditions, is applied to selected persistent organic pollutants (POPs) in the surface 'skin' (1 mm) of soils. MRC is calculated as a function of soil organic matter (SOM) content and temperature-dependent K(OA) and mapped globally for selected PCB congeners (PCB-28; -153; -180) and HCB, to identify regions with a higher tendency to retain POPs. It is shown to vary over many orders of magnitude, between compounds, locations and time (seasonally/diurnally). The MRC approach emphasises the very large capacity of soils as a storage compartment for POPs. The theoretical MRC concept is compared to reality and its implications for the global cycling of POPs are discussed. Sharp gradients in soil MRC can exist in mountainous areas and between the land and ocean. Exchanges between oceans and land masses via the atmosphere is likely to be an important driver to the global cycling of these compounds, and net ocean-land transfers could occur in some areas.

Air Pollution↗