Nitroaromatics are typical toxic organic pollutants and are ubiquitous in environment with diverse structures. They are widely used in many industries and formed during many natural and anthropogenic processes. Most o...
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Nitroaromatics are typical toxic organic pollutants and are ubiquitous in environment with diverse structures. They are widely used in many industries and formed during many natural and anthropogenic processes. Most of these pollutants are potentially carcinogenic and the as-sessment and prediction of the mutagenicity of nitroaromatics are of great interest. In this paper the structure-mutagenicity relationships of 219 nitroaromatics are investigated by molecular or-bital theory based classic structure-activity relationships and comparative molecular field analysis (CoMFA). A comparison is undertaken in respect of the interpretation of mechanism and predic-tive ability for these two categories of QSAR approaches and highly predictive QSAR models have been developed.
Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time （RRT） of polybrominated diphenyl ethers （PBDEs） were predic...
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Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time （RRT） of polybrominated diphenyl ethers （PBDEs） were predicted. A four-variable regression model （M30） with the correlation coefficient of 0.9816 and the root mean square errors of 0.061 was developed using a training set including 30 PBDEs. The correlation coefficient of 0.9841 and the root mean square errors of 0.054 between the values of RRT predicted by M30 and the RRT observed for 16 external PBDEs show a good predictive potential of M30. The descriptors included in the M30 represent four interactions between four pairs of atom types, i.e., atom -C= and -C=, -C= and 〉C=, 〉C= and 〉C=, -C= and -Br.
Nowadays soils of most part of the world have been seriously polluted by heavy metals and organic *** soils have caused a lot of problems,such as underground water pollution,ecosystem damage,environment deterioration,...
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Nowadays soils of most part of the world have been seriously polluted by heavy metals and organic *** soils have caused a lot of problems,such as underground water pollution,ecosystem damage,environment deterioration,and so *** the progress of
In this paper, a practical and operative method is presented for water quality classification in Lake Tai using multi-spectral remote sensing data. The remote sensing models of chlorophyll-a and suspended sediments ar...
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In this paper, a practical and operative method is presented for water quality classification in Lake Tai using multi-spectral remote sensing data. The remote sensing models of chlorophyll-a and suspended sediments are developed by integration of Landsat5 TM images and in situ measurements in the period of from year 2003 to 2004. The key issues in applying multi-spectral satellite imagery to water quality are first given, including radiation calibration, geometric correction, atmospheric correction, noise elimination by spatial filtering and the spectral reflectance obtain. The multi-spectral band analysis is further studied to determine the relations between various bands emissivity, the emissivity combination and the water quality parameters. The regression models for chlorophyll-a and suspended sediments are derived, and the accuracies and correlation coefficients of the models are analyzed. The water quality parameters obtained from the regression models are tested with the in situ measurements, which proves the uniformity between these two results. This means the feasibility of the multi-spectral remote sensing data for monitoring the water quality in Lake Tai.
The affect of two kinds of volatile fatty acids (VFAs) ratio (propionic acid acetic acid) on enhanced biological phosphorus removal (EBPR) in wastewater was studied in sequencing batch reactors (SBR). The suddenly inc...
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The affect of two kinds of volatile fatty acids (VFAs) ratio (propionic acid acetic acid) on enhanced biological phosphorus removal (EBPR) in wastewater was studied in sequencing batch reactors (SBR). The suddenly increasing propionic acid acetic acid ratio caused the variation in short-term system biological phosphorus removal effect. But after domestication for a period of time acclimation, the phosphorus removal effect was improved markedly;the removal efficiency of soluble orthophate (SOP) was about 10% greater than that before the change of propionic acid acetic acid ratio. Further study showed that the reason for the obvious enhancement of phosphorus removal efficiency was mainly the SBR2 system lower second phosphorus release amount.
Synthetic boron-doped diamond film has received great attention recently,because of its excellent electrochemical behaviors and its promising *** with conventional electrode materials such as glassy carbon and highly ...
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Synthetic boron-doped diamond film has received great attention recently,because of its excellent electrochemical behaviors and its promising *** with conventional electrode materials such as glassy carbon and highly oriented pyrolytic graphite,
To understand pollution level and possible sources of atmospheric fine particulates in rural areas of southern Jiangsu Province of China, samples of PM2.5 were collected and analyzed in Xueyan Town and Taihu Lake Stat...
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To understand pollution level and possible sources of atmospheric fine particulates in rural areas of southern Jiangsu Province of China, samples of PM2.5 were collected and analyzed in Xueyan Town and Taihu Lake Station over three seasons from July 2002 to January 2003. The mass concentrations of PM2.5 and 14 principal component elements were obtained. The results showed that pollution of PM2.5 was serious and the concentration levels of S, Zn, Pb and As were similar to city. There are different seasonal distribution laws of pollutant elements in PM2.5 between two sampling sites, probably due to contribution of local sources, medium or long distance transportation of fine particulates and complicated meteorological conditions. The enrichment levels of S, Zn, Pb, As, K were high, reflecting the influence of anthropogenic activities. Particularly enrichment level of S was much higher in summer, which was probably related to meteorological condition. The result of principal components analysis showed major sources of PM2.5 included crustal resuspension, coal burning, metal processing industry or waste incineration, vehicular emission, which suggests anthropogenic activities is of important influence on PM2.5 in rural areas of southern Jiangsu Province.
X-ray photoelectron spectroscopy(XPS)was adopted to elucidate sorption mechanism of phenol and p-nitrophenol onto a weakly anion exchanger *** distribution of specific forms of tertiary amino group on D301 was obtaine...
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X-ray photoelectron spectroscopy(XPS)was adopted to elucidate sorption mechanism of phenol and p-nitrophenol onto a weakly anion exchanger *** distribution of specific forms of tertiary amino group on D301 was obtained and effect of free tertiary amino group on phenol sorption onto D301 was discussed. The result indicated that the percent of the protonated tertiary amine group on polymeric matrix was much lower than the reference compound N,N-dimethylbenzylamine at an identical pH value in solution due to the much lower activity degree of hydrogen ion in inner resin phase than in the external solution. Less free amino group on D301 results in less sorption capacity of phenol and p-nitrophenol in an acidic solution. Under the experimental conditions both phenol sorption onto D301 can be explained as solid extraction and the distribution coefficient varies linearly with the content of free amino group on D301.
The adsorption properties, including the adsorption isotherms, thermodynamics and kinetics, of 1-amino-2- naphthol-4-sulfonic acid (1,2,4-acid) onto weakly basic resin ND900 are investigated. Both the Langmuir and Fre...
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The adsorption properties, including the adsorption isotherms, thermodynamics and kinetics, of 1-amino-2- naphthol-4-sulfonic acid (1,2,4-acid) onto weakly basic resin ND900 are investigated. Both the Langmuir and Freundlich equations can give a good fit to the adsorption isotherms, which indicates an endothermic and a favorable adsorption in our study range. A high yield in elimination of about 45.21 %-97.28% is obtained for the tested adsorption systems. The capacity and affinity of the adsorption increase with temperature, due to the phenomena of 'solvent-motivated' effects. The value of is 51.59 kJ/mol, which indicates a chemical adsorption and then expects the poor desorption property of ND900. The negative value of indicates the spontaneous nature of the adsorption process, and the positive value of shows the increased randomness at the solid/solution interface during the adsorption process. The value of the adsorption rate constant lower than 0.013 min-1 is indicative of a slow adsorption rate. The intra-particle diffusion must be one of the rate limiting steps.
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