Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems

Degradation of a nonphenolic β-O-4 lignin model dimer by horseradish peroxidase with 1-hydroxybenzotriazole

autho

Enzymatic decolorization of textile dyeing effluents

Commercial azo, triarylmethane, antraquinonic, and indigoid textile dyes are efficiently decolorized with enzyme preparations from Pleuratus ostreatus, Schizophyllum commune, Neurospora crassa, Polvporus sp., Sclerotium rolfsii, Trametes villosa, and Myceliophtora thermophila. The nature of substituents on the dyes' benzene rings influences enzyme activity, and hydroxyl and amino groups enhance decolorization. The presence of lignin peroxidase and/or manganese peroxidase in addition to Iaccase (P. Ostreatus, S. commune, S. rolfsii, N. crassa) increases decolorization by up to 25%, The effect of textile dyeing auxiliaries depends on the individual enzymes. Polyporus sp. and T. villosa are inhibited up to 20% by copper and iron chelating agents and anionic detergents, while the S. Commune enzymes lose up to 70% of their activity