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Wang Y.R.,Chongqing University | Lia W.P.,Chongqing University | Liaob S.G.,Chongqing Solid Wastes Management Center
ECS Transactions | Year: 2010

In this study, electrodeposition of Pb on polycrystalline Cu surface has been investigated by cyclic voltammetry (CV). Simultaneous in real time ellipsometry (SE) have been performed to study the characterization and morphological evolution of the Pb layer. The results demonstrated that the rate at which deposition thickness is increasing is going up and revealed that thin Pb deposition layer has already acquired at all the polarization process. So the Cu substrate is not optically ignored during the total polarization process. ©The Electrochemical Society. Source

Zhou X.,Southwest University | Zhang J.-Y.,Southwest University | Zhang J.-Y.,Neijiang Normal University | Wang D.-Y.,Southwest University | And 4 more authors.
Huanjing Kexue/Environmental Science | Year: 2016

Mercury removal from aqueous solutions of HgCl2 was studied by indoor simulation experiments, and the effects of three different diameter of particles of Nano-TiO2 (Nano-Titanium Dioxide) at different dosage, pH, adsorption time and the initial concentration of Hg2+ on the mercury adsorption from simulated wastewater were investigated. The single factor experiments showed that the optimal conditions were: 7.5g·L-1 of 5 nm TiO2 or 2.0g·L-1 of 100 nm TiO2, pH 8.0, initial concentration of Hg2+15 mg·L-1, adsorption time 5 min, and under these conditions the adsorption rates reached 99.5% and 99.3%, relatively. When the content of 25 nm TiO2 was 10g·L-1, and the other conditions were pH 8.0, initial concentration of Hg2+ 15mg·L-1, adsorption time 60 min, the adsorption rate was 62.8%. The Hg(II) removal effects of the TiO2 particles with different diameters followed the order of 100 nm TiO2>5 nm TiO2>25 nm TiO2. Component adsorption results showed that the 5 nm TiO2 component adsorption effect was superior to its single adsorption effect, while there was little difference between 100 nm TiO2 component adsorption effect and its single adsorption effect. The results of orthogonal experiments indicated that the influencing factors of the adsorption rate followed the order of pH>the initial concentration of Hg2+>time>dosage. The optimal experiment scheme was: pH 8.0, a dosage of 100 nm Nano-TiO2 of 2.0 g·L-1, an initial Hg2+ concentration of 25 mg·L-1 and adsorption time of 10 min. Under the experimental conditions, the maximum adsorption rate reached 99.9%, at the same time, the equilibrium concentration of Hg(II) was 0.033 mg·L-1<0.05 mg·L-1, below the current enterprise rules of water pollutants in mercury emissions limits. In addition, the maximum adsorptive capacity was 26.95 mg·g-1. The adsorption isotherm was in line with the Langmuir isotherm equation, indicating that the Hg(II) uptake by 100 nm Nano-TiO2 was typical monolayer adsorption. © 2016, Science Press. All right reserved. Source

Zhang Y.-H.,Southwest University | Zhang C.,Southwest University | Zhang C.,Chongqing Key Laboratory of Agricultural Resources and Environment | Wang D.-Y.,Southwest University | And 4 more authors.
Huanjing Kexue/Environmental Science | Year: 2015

To preliminarily discuss the mercury emission characteristics and its mass balance in each process of the iron and steel production, a typical iron and steel enterprise was chosen to study the total mercury in all employed materials and estimate the input and output of mercury during the steel production process. The results showed that the mercury concentrations of input materials in each technology ranged 2.93-159.11 μg·kg-1 with the highest level observed in ore used in blast furnace, followed by coal of sintering and blast furnace. The mercury concentrations of output materials ranged 3.09-18.13 μg·kg-1 and the mercury concentration of dust was the highest, followed by converter slag. The mercury input and the output in the coking plant were 1346.74 g·d-1±36.95 g·d-1 and 177.42 g·d-1±13.73 g·d-1, respectively. In coking process, mercury mainly came from the burning of coking coal. The sintering process was the biggest contributor for mercury input during the iron and steel production with the mercury input of 1075.27 g·d-1±60.89 g·d-1 accounting for 68.06% of the total mercury input during this production process, and the ore powder was considered as the main mercury source. For the solid output material, the output in the sintering process was 14.15 g·d-1±0.38 g·d-1, accounting for 22.61% of the total solid output. The mercury emission amount from this studied iron and steel enterprise was estimated to be 553.83 kg in 2013 with the emission factor of 0.092 g·t-1 steel production. Thus, to control the mercury emissions, iron and steel enterprises should combine with production practice, further reduce energy consumption of coking and sintering, or improve the quality of raw materials and reduce the input of mercury. © 2015, Science Press. All right reserved. Source

Zhang C.,Southwest University | Zhang C.,Chongqing Key Laboratory of Agricultural Resources and Environment | Wang Y.,Southwest University | Zhang Z.,Southwest University | And 5 more authors.
Journal of Residuals Science and Technology | Year: 2015

A systematic survey of heavy metals and As concentrations in vegetables and soil in Chongqing was carried out to assess their potential health risks to local people. The results indicated that the Cr, Cd, Pb and As levels in some vegetables exceeded the Chinese safety standard of pollutants in food. The total carcinogenic risks of the heavy metals and As in 10 kinds of vegetables were all over the standard limits provided by USEPA and ICRP. Therefore, great attention should be paid to the issues of the heavy metals and As pollution in vegetables and the corresponding soil. © 2015 DEStech Publications, Inc. Source

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