Cadmium is one of the most toxic elements, which are seriously harmful to human health. Removal of cadmium (II) from aqueous solution, especially from the drinking water, is extraordinary important and indispensable. ...
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Cadmium is one of the most toxic elements, which are seriously harmful to human health. Removal of cadmium (II) from aqueous solution, especially from the drinking water, is extraordinary important and indispensable. The new method to obtain the modified activated carbon was proposed. The physical and chemical characteristics of the adsorbents were studied. The adsorption capacities of the modified activated carbon and virgin activated carbon were compared through removing cadmium (II) from aqueous solution. The effects of the pH value on the cadmium (II) adsorption have been investigated. Meanwhile, the Freundlich and Langmuir models were employed to characterize the experimental results by data fit method. Results show that the adsorption of cadmium (II) is greatly improved by using the modified activated carbon. The experimental results are better close to the Freundlich isotherm, compared to the Langmuir isotherm.
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.
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.
Carbonaceous adsorbents (CA) were prepared by carbonizing waste cation-exchange resins in different temperature and followed by CO2 activation. The results of elementary analysis and FT-IR indicated sulfonic groups in...
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Carbonaceous adsorbents (CA) were prepared by carbonizing waste cation-exchange resins in different temperature and followed by CO2 activation. The results of elementary analysis and FT-IR indicated sulfonic groups in resins inner surface were almost decomposed to heat-resistant sulfone groups after pyrolysis. The BET surface area of CA could achieve 340.1 m2/g. Also, the study of adsorbing phenol in aqueous was carried out. The result showed the adsorption capacity for phenol was about 57.60 mg/g, and there was a good linear correspondence between the adsorption capacity for phenol and BET surface area;in the concentration of phenol ranged from 25.5 mg/L to 600.0 mg/L, adsorption isotherm could be fitted well into Langmuir equation.
Focusing on the region of Yarlung Zangbo River and the middle reaches of its two tributaries of Nianchu River and Lhasa River in Tibet (Hereafter referred to as the One River and Two Tributaries region), and based on ...
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Focusing on the region of Yarlung Zangbo River and the middle reaches of its two tributaries of Nianchu River and Lhasa River in Tibet (Hereafter referred to as the One River and Two Tributaries region), and based on the data from China 3rd, 4th and 5th population censuses, the article has analyzed change patterns of this region's labor force. Major findings from the study are summarized as follows: (1) Compared with the data from the 3rd census, labor force population in 2000 has increased significantly. (2) Children dependency coefficient has dropped, while old people dependency coefficient has changed very slightly with an increase of 0.047% only. (3) Compared 2000 with 1982, illiteracy and semi-illiteracy rate of the population above 15 years old have decreased significantly by 30.69 percentage points, but still higher than the national average. (4) Women's illiteracy rate has dropped faster than men's, but up to 2000 it was generally quite high. The upgrading of the entire population's overall quality has a long way to go.
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.
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.
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
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,
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