ABSTRACT
The objective of this study was to evaluate the ozone oxidation of dissolved heavy metals in an abandoned mine drainage (AMD) by conducting a pilot-scale operation at two different ozone doses of 7.5 and 24.0 g O(3)/h into an ozone reactor. A portion of the abandoned mine drainage near the Jungam Mine in Samchuck, Korea was pumped into this pilot-scale plant and used as an influent for the ozone oxidation. Some possible precipitates of metal oxides and hydroxides that resulted from the pilot-scale ozone oxidation of the dissolved Fe and Mn ions in the AMD (with a hydraulic retention time of 106 seconds in the ozone reactor) were effectively removed via sand filtration. A six-hour ozone oxidation with an ozone dose of 24.0 g O(3)/h and subsequent sand filtration, before backwashing the sand filter bed, can meet Korean drinking water quality standards (less than 0.3 mg/L) for Fe and Mn in the sand filter effluent under the operating conditions that were used in this study. The SO(4)(-2) concentrations and alkalinities of the influents were not affected by the ozone oxidation. The pH values of the influents were neutral or slightly alkaline, and after the six-hour oxidation, increased very slightly. These experiment results show that the ozone oxidation of dissolved heavy metals and the subsequent sand filtration of metal precipitates are desirable alternatives to removing heavy metals in an abandoned mine drainage.
Subject(s)
Industrial Waste/analysis , Metals, Heavy/chemistry , Mining , Ozone , Waste Disposal, Fluid/methods , Oxidation-Reduction , Pilot ProjectsABSTRACT
A method of calculating Km and V from a single reaction progress curve is presented. The integrated Michaelis-Menten equation Vt = So + Km 1n(So/S), may be rearranged to the form 1/v = 1/V + Km/VS, where v = (Si - Sj)/deltat = deltaS/deltat and S = (Si - Sj)/ln(Si/Sj) or S is approximated by (Si + Sj)/2.Si and Sj represent substrate concentrations at two points along a reaction progress curve separated by the time interval, deltat. The error resulting from the approximation depends on the magnitude of deltaSi/Si; when deltaSi/Si less than 0.3, the error is insignificant; when deltaSi/Si greater than 0.3, the error becomes significant. Procedures are presented to correct this error. Simulated data and application to the direct spectrophotometric assay of AMP aminohydrolase and the lactate dehydrogenase coupled assay of pyruvate kinase are provided. The method is recommended when routine Km and V values are desired. Compared to the initial rate method, it is faster, requires less substrate, and eliminates pipetting errors.
Subject(s)
Enzymes/metabolism , Kinetics , Evaluation Studies as Topic , Mathematics , Methods , Time FactorsSubject(s)
Pyruvate Kinase/analysis , Saccharomyces cerevisiae/enzymology , Ammonium Sulfate , Buffers , Chromatography , Chromatography, DEAE-Cellulose , Chromatography, Gel , Fractional Precipitation , Hydrogen-Ion Concentration , Kinetics , Methods , Molecular Weight , Pyruvate Kinase/isolation & purification , SpectrophotometryABSTRACT
A revised preparation of pyruvate kinase from saccharomyces cerevisiae is reported. By purifying this cold-labile enzyme at room temperature, an improved recovery and specific activity was obtained. More than 350 mg of pure enzyme with a specific activity of 350 to 400 units/mg at 30 degrees were obtained from a pound of fresh yeast. The last step of the preparation, passage of the enzyme over Sephadex G-100, was required to remove a contaminating protease. The molecular parameters of the new preparation are: molecular weight, 209,000; four subunits of identical size; E 280 nm, 0.51; pI 6.6; and pH optimum, 6.28. Kinetic parameters are: Km for P-enolpyruvate and ADP, 0.09 and 0.18 mM in the presence of saturating Fru-1,6-P2, and 1.8 and 0.34 mM in the absence of Fru-1,6-P2; Ka for Fru-1,6-P2, 0.014 mM. No free NH2-terminal amino acid could be detected. Amino acid composition was determined and compared with other pyruvate kinase preparations.