RESUMEN
The title mononuclear complex, [Cu(C(18)H(12)N(2)O(2))(C(12)H(8)N(2))]·CH(3)OH, contains one N'-[(2-oxidonaphthalen-1-yl)methyl-idene]benzohydrazidate ligand (L(2-)), a Cu(2+) cation, one 1,10-phenanthroline ligand and a methanol solvent mol-ecule. The Cu(II) ion adopts a CuO(2)N(3) distorted square-pyramidal coordination. An O-Hâ¯O hydrogen bond is formed between the methanol solvent mol-ecule and the hydrazide O atom of the L(2-) ligand.
RESUMEN
Metal oxides( Fe, Mn oxides) in natural surface coatings(biofilms and associated minerals) are believed to play a significant role in the fate and transport of trace metal in aquatic environments. Seasonal variation of Fe, Mn oxides and organic materials in surface coatings, which were developed periodically on glass slides in Nanhu Lake, Jilin Province, China over the time frame of three seasons, was investigated in order to understand the influence of metal oxides on Pb and Cd adsorption to heterogeneous surface coating materials (biofilm). Pb and Cd adsorption was measured under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0.05 mol/L, 25 degrees C and pH 6.0). The classical Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb and Cd adsorption to the surface coatings. In general, components in the surface coatings varied greatly with seasons altering and obtained higher concentrations in summer while the content of iron oxides always exceeded that of manganese oxides. Correlation analyses between the maximum adsorption of Pb and Cd and components in the surface coatings developed periodically indicated that Pb phase association with Mn oxides and Cd phase association with Fe oxides as well as Mn oxides were statistically significant. Effect of Mn oxides on Cd adsorption was confirmed in view of its higher content in the surface coatings. The importance of ferromanganese oxides for Pb and Cd adsorption to the natural surface coatings developed in different seasons was evidenced.
Asunto(s)
Biopelículas , Agua Dulce/química , Metales Pesados/química , Óxidos/química , Estaciones del Año , Adsorción , China , Análisis de Regresión , Espectrofotometría AtómicaRESUMEN
Surface coatings and surficial sediments were obtained in four natural waters in Xianghai Wetland in China to study the role of surface coatings and surficial sediments in controlling the transporting and cycling of heavy metals in aquatic environments. Pb and Cd adsorption to the surface coatings and surficial sediments were measured under controlled laboratory conditions(mineral salts solution with defined speciation, ionic strength 0.05 mol/L, 25 degrees C and pH 6.0 for surface coatings; and 0.005 mol/L CaCl2 solution, 25 degrees C and pH 6.0 for surficial sediments). The Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb and Cd adsorption to the surface coatings and surficial sediments, and the component analyses of surface coatings and surficial sediments were also carried out. Correlation analyses between the maximum adsorption of Pb and Cd (adsorption max ) and the components in the surface coatings and surficial sediments suggested that there was a statistically significant trend for Pb and Cd adsorption( adsorption max ) to the surface coatings to increase with increasing in contents of Fe and Mn oxides in the surface coatings and surficial sediments. And the metal adsorption abilities of surface coatings were much stronger than those of surficial sediments, highlighting that in the same water, i.e. at the same pH and initial metal concentrations, the metals (such as lead and cadmium) in supernatant were feasible to be adsorbed by surface coatings than surficial sediments. The more importance of surface coatings than surficial sediments for adsorbing and cycling of heavy metals in aquatic environments was evidenced.
Asunto(s)
Biopelículas , Cadmio/análisis , Monitoreo del Ambiente/estadística & datos numéricos , Sedimentos Geológicos/análisis , Plomo/análisis , Adsorción , China , Concentración de Iones de Hidrógeno , Espectrofotometría AtómicaRESUMEN
A new approach applying fuzzy mathematic theorems, including the Primary Matrix Element Theorem and the Fisher Classification Method, was established to solve the optimization problem of atmospheric environmental sampling sites. According to its basis, an application in the optimization of sampling sites in the atmospheric environmental monitoring was discussed. The method was proven to be suitable and effective. The results were admitted and applied by the Environmental Protection Bureau (EPB) of many cities of China. A set of computer software of this approach was also completely compiled and used.
Asunto(s)
Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Lógica Difusa , Modelos Teóricos , Tamaño de la Muestra , Manejo de EspecímenesRESUMEN
Pb adsorption capacities of Fe oxide, Mn oxide and organic materials in natural surface coatings( biofilms and associated minerals) collected in three lakes, two ponds and a river in Jilin Province, China and Cayuga Lake in US were studied. A novel extraction technique was employed to remove one or more component(s) from the surface coatings. Pb adsorption to surface coatings before and after extraction was performed to determine the adsorptive properties of the extracted component(s). The statistical analysis of observed Pb adsorption was carried out using nonlinear least squares fitting(NLSF) to estimate the Pb adsorption capacity of each component of surface coatings. For each body of water, the estimated Pb adsorption capacity of Mn oxide(mol Pb/mol Mn) was significantly higher than that of Fe oxide(mol Pb/ mol Fe). The value of estimated adsorption capacities of organic materials with the unit mol Pb per kg COD was similar to or less than that of Fe oxides with the unit mol Pb per mol Fe. Comparison of components of surface coatings in different waters showed that the estimated Pb adsorption capacities of components in surface coatings developed in different natural waters were different, especially for Mn oxides.
Asunto(s)
Biopelículas , Plomo/química , Contaminantes del Agua/análisis , Purificación del Agua/métodos , Adsorción , Ensayo de Materiales , Minerales , Compuestos OrgánicosRESUMEN
The sorption kinetics and thermodynamics of 1,3-dinitrobenzene (DNB), m-nitrotoluene (mNT), p-nitrophenol (pNP), and nitrobenzene (NB) on as-grown and nitric acid-oxidized multiwalled carbon nanotubes (MWCNTs) were investigated. The sorption kinetics was well described by a pseudo-second-order rate model, while both Langmuir and Freundlich models described the sorption isotherms well and the sorption thermodynamic parameters of equilibrium constant (K(0)), standard free energy (DeltaG), standard enthalpy (DeltaH), and standard entropy changes (DeltaS) were measured. The values of DeltaH and DeltaG suggested that the sorption of nitroaromatics (NACs) onto MWCNTs was exothermic and spontaneous. The structure, number, and position of nitro groups of NACs were the main factors affecting the sorption rate and capacity. Treatment of the MWCNTs with nitric acid increased both the surface area and the pore volume and introduced oxygen-containing functional groups to the MWCNTs, which depressed the sorption of NACs onto MWCNTs.