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Metsulfuron methyl is typical sulfonylurea herbicides. The degradation of metsulfuron-methyl has aroused research interests because it was mobile in natural media, and raising environmental concerns about contamination of metsulfuron-methyl to surface water. However, conventional methods cannot remove these herbicides from water efficiently. This work proposed a rapid and efficient enzymatic degradation of metsulfuron-methyl by chloroperoxidase (CPO). The effect of reaction conditions, including pH, concentration of oxidant and enzyme, and degradation time on the degradation efficiency (η) were studied and accordingly optimized. The optimum η of 93.2% for 16.7 μmol·L−1 metsulfuron-methyl was achieved after 10 min at 25 °C and weakly acidic pH. The required CPO is only 0.06 μmol·L−1. The degraded products of metsulfuron-methyl were identified by HPLC-MS. The results indicated that metsulfuron-methyl molecule was decomposed, and five smaller molecular fragments were detected. Moreover, it was found that if this enzymatic degradation was combined with following activated sludge treatment, then, this bio-cascade treatment was more effective in removal of metsulfuron-methyl in wastewater than by activated sludge alone (which was used in most municipal sewage plant). The COD removal increased from 12.09% to 74.27%. Ecotoxicity tests of 72 h EC50 for degraded solution using a green alga, Chlorella pyrenoidosa, as eco-indicator demonstrated the enzymatic degraded products had lower eco-toxicity than metsulfuron-methyl itself. Application of this bio-cascade treatment to real water sample and artificial wastewater containing metsulfuron-methyl was effectively. [ABSTRACT FROM AUTHOR]

The solubility, density, and refractive index data for 1,2-propanediol + Cs2SO4 + H2O, ethylene glycol + Cs2SO4 + H2O, and glycerin + Cs2SO4 + H2O ternary systems were determined at 15°C, 25°C, and 35°C. In all cases, the solubility of Cs2SO4in aqueous solutions decreased significantly due to the presence of the polyhydric alcohol. The experimental density, refractive index, and solubility data of saturated solutions for these systems were correlated using polynomial equations. Furthermore, the refractive index and density of unsaturated ternary solutions were also determined and correlated with salt concentrations and proportions of polyhydric alcohol in these systems. [ABSTRACT FROM PUBLISHER]

The solubilities, densities, and refractive index data for the 1,2-propylene glycol + MNO3 + H2O (M = Na, K, Rb, Cs) ternary systems at 25° and 35°C were measured with mass fractions of 1,2-propylene glycol ranging from 0 to 1.0. In all cases, the presence of 1,2-propylene glycol significantly reduces the solubility of the salts in aqueous solution. The experimental data of density, refractive index, and solubility of saturated solutions for these systems were correlated using polynomial equations. Furthermore, the refractive index and density of unsaturated ternary solutions were also determined and correlated with the salt concentrations and proportions of 1,2-propylene glycol in the systems. [ABSTRACT FROM PUBLISHER]