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Ji D.,Water Resources University | Yang Q.,Water Resources University | Wang Y.,China National Environmental Monitoring Station | Meng F.,Chinese Research Academy of Environmental Sciences
Fresenius Environmental Bulletin | Year: 2015

This study investigated the dechlorination of 1, 1-DCE with nPd/Fe particles under different temperatures. The dechlorination rates with nPd/Fe were significantly faster than those with nZVI particles. According to the XPS spectra, the palladium was present on the iron surface in the elemental state and there were more Fe0 oxidized to Fe3+ on the surface of aged nPd/Fe particles than fresh nPd/Fe particles. Activation energies of the dechlorination reactions with the nPd/Fe and nZVI particles are estimated to be 38.90 kJ/mol and 55.18 kJ/mol, respectively. Based on rigorous analysis of the thermodynamics parameters, the dechlorination of 1, 1-DCE was a non-spontaneous and endothermic process. Moreover, analysis of the reaction products demonstrated that 1, 1-DCE was completely dechlorinated to the ethane and ethylene without toxic intermediate. In addition, Both XPS analysis and the temperature-dependent study indicated that the hydrodechlorination reaction occurring in the presence of nPd/Fe particles is a catalytic reaction. Palladium on the zero-valent iron surface serving as a catalyst, could provide more surface active sites so as to facilitate and speed up the reaction. Source


Ji D.,Water Resources University | Yang Q.,Water Resources University | Wang Y.,China National Environmental Monitoring Station | Xi H.,Chinese Research Academy of Environmental Sciences
Fresenius Environmental Bulletin | Year: 2015

A bacteria strain P-l which was capable of utilizing phenanthrene as the sole carbon and energy source, was isolated from municipal activated sludge using an enrichment method. On the basis of the morphology, biochemical properties and the 16S rDNA sequence analysis, the strain was identified as Sphingobacterium multivorum. Volatilization, adsorption and degradation behaviors of phenanthrene (at initial concentration of 0.854 mg/1) caused by the strain P-l were investigated respectively at temperature of 28 °C and pH 7.2, almost complete degradation of phenanthrene was observed within 25 h. Moreover, the adsorption process well followed the pseudo first-order kinetics and the adsorption rate constant ka = 4.596 h-1; both volatilization and degradation processes were in line with the pseudo first-order kinetics equation, the volatilization rate constant kv = 0.0581 h-1, the degradation rate constant kd = 0.1050 h-'. Accordingly, biodegradation model for the time evolution of phenanthrene concentration was established and verified. Furthermore, isolation of the bacteria strain P-l in the study confirmed that bacteria Sphingobacterium multivorum played an important role in degradation of PAHs in the municipal sewage. © by PSP Volume 24 - No 1. 2015. Source


Bai L.,Chinese Research Academy of Environmental Sciences | Bai L.,Engineering Research Center for Groundwater Pollution Control and Remediation | Wang Y.,China National Environmental Monitoring Station | Li F.,Chinese Research Academy of Environmental Sciences | Li F.,Engineering Research Center for Groundwater Pollution Control and Remediation
Advanced Materials Research | Year: 2012

The risk assessment model and parameter system of groundwater pollution were established in this paper. The multi-index evaluation method of groundwater pollution sources was proposed, and the GIS-based risk assessment method of groundwater pollution was produced in comprehensive consideration of groundwater vulnerability and groundwater pollution sources. The multi-index method suggested in this paper was used in the risk assessment of groundwater pollution at a plain area of a big city in North China, and the different grades of groundwater pollution risk were computed. The evaluation results show that the groundwater pollution risk is determined by the combined action of pollution sources and groundwater vulnerability. The established risk assessment method of groundwater pollution could give a scientific support for the regional groundwater pollution prevention and control planning. © (2012) Trans Tech Publications, Switzerland. Source


Bai L.-P.,Chinese Research Academy of Environmental Sciences | Wang Y.-Y.,China National Environmental Monitoring Station | Guo Y.-L.,Beijing Normal University | Zhou Y.-Y.,Chinese Research Academy of Environmental Sciences | And 3 more authors.
Huanjing Kexue/Environmental Science | Year: 2014

Groundwater is the main source of water supply in China, and China's overall situation of groundwater pollution is not optimistic at present. Groundwater pollution risk evaluation and early-warning are the effective measures to prevent groundwater pollution. At present, research of groundwater early-warning method at home and abroad is still at the exploratory stage, and the sophisticated technology has not been developed for reference. This paper briefly described the data and technological demand of the early-warning method in different scales, and the main factors influencing the early-warning results of groundwater pollution were classified as protection performance of geological medium, characteristics of pollution sources, groundwater dynamics and groundwater value. Then the main early-warning indexes of groundwater pollution were screened to establish the early-warning model of regional or watershed scale by the index overlay method. At last, the established early-warning model was used in Baotou plain, and the different early-warning grades were zoned by the model. The research results could provide scientific support for the local management department to protect the groundwater resources. Source


Bai L.,Chinese Research Academy of Environmental Sciences | Wang Y.,China National Environmental Monitoring Station | Zhou Y.,Chinese Research Academy of Environmental Sciences | Liu L.,Chinese Research Academy of Environmental Sciences | And 2 more authors.
Water Science and Technology: Water Supply | Year: 2016

A universal method to evaluate groundwater pollution risk with the site scale has not beenestablished. The groundwater pollution risk is commonly evaluated by overlaying the results of groundwater vulnerability and pollution sources, but this method is inapplicable for contaminated sites. Considering the current supervision demands of groundwater pollution in China, this paper suggests a risk evaluation method for contaminated sites. The present and forecasted groundwater pollutant concentrations and the variation trend of groundwater quality were used to get the risk classes of groundwater pollution. Chromium is one of the most common groundwater contaminants found at industrially contaminated sites. A chromium residue disposal site in Baotou, China was selected as the study area. The groundwater flow model and solute transport model were constructed by MODFLOW and MT3DMS. Based on the simulation results of the numerical model, the groundwater pollution risk of the contaminated site was divided into four classes, and the regulation measures of groundwater pollution were suggested. This study could provide guidance for the environmental supervision and management of contaminated sites. © IWA Publishing 2016. Source

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