Papers by Keyword: Hg

Abstract: There is an increasing concern about heavy metal contamination in farmland in China and worldwide.In order to reveal the spatial features of heavy metals in the soil-vegetable system in the CFL manufacturing area, a total of 18 pairs of soil and vegetable samples were collected from Gaohong, Southeastern China. Most of the heavy metals in soil were much higher than its corresponding background value in Zhejiang province,Most of the heavy metals in the vegetable exceeded the Safe Agricultural Product Standard in China.Compared to other heavy metals, Hg had the highest enrichment index. The CFL manufacturing companies were the main source of heavy metal Hg pollution in this area. There are strong correlation between THg in soil and vegetable.

Abstract: Based on the investigation data of mercury (Hg) in waters in Jiaozhou bay during time peroids of 1979 to 1985 (absent of 1984), this paper tried to analysis the seasonal variations of Hg in Jiaozhou Bay, to reveal the transfer process of Hg, and to provide basis for decision-making of pollution control. Results showed that, there was indistint seasonal variations of Hg content, due to anthropogenic discharge was the major source of Hg, which was not static, but depended on industrial adjustment. The land transfer process of Hg could be divided into three major processes: 1) human discharges of Hg to soil, waters, and atmosphere, etc., 2) Hg is washouted and delivered into streams, and 3) Hg is transferred to ocean via river channel runoff. In order to reconcile economic growth with environmental protection, we should have to improve the use ratio of Hg, and to reduce the discharge load of Hg.

Abstract: Based on the investigation data of Hg in Jiaozhou Bay waters in April, July and October 1986, this paper tried to analysis the horizontal, vertical and seasonal distributions of Hg in Jiaozhou Bay, and to reveal the pollution sources and transfer processes of Hg. Results showed that Jiaozhou Bay had been heavily polluted by Hg, whatever in different seasons. Hg in Jiaozhou Bay was mainly from point sources such as industrial waste and sewage runoff. The horizonal and vertical distributions of Hg content showed the transfer processes as, from estuaries to their outside and the bay mouth, and form surface waters to bottom waters, respectively. The water environmental capacity of Hg in Jiaozhou Bay had been unable to carry the emission load of Hg, and therefore the reduction of emission as well as the improvement of cyclic utilization ratio were the primary processes for Hg pollution prevention and reduction.

Abstract: Based on investigation data in Jiaozhou bay waters from 1979 to 1985(absent of 1984), this paper tried to anylysis the horizontal distributions and pollution sources and characteristics of Hg in Jiaozhou Bay. The results showed that, the horizonal distributions of Hg in surface water of Jiaozhou Bay showed decreasing trends from river flow direct, and the major pollution source of Hg was point source, whose pollutants were transferred by stream discharge. Under the influences of point source pollution, the Hg concentrations in surface waters could range from 0.46-13.04 μg.L^-1; while under the influences of ocean current itself, the concentration of Hg in bay mouth area could range from 0.46-13.04 μg.L^-1. The pollution sources of Hg in Jiaozhou Bay could be catagoried as two levels as high-pollution sources and non-pollution sources, due to Hg in this bay was mainly impacted by point source. It is necessary to enhance the recovery ratio of Hg, and to reduce the discharge of Hg.

Abstract: Based on the investigation data of mercury (Hg) in waters in Jiaozhou bay during time peroids of 1979 to 1985 (absent of 1984), this paper tried to analysis the content, pollution level and theis temporal variations of Hg in Jiaozhou Bay, to reveal the changing trend of Hg, and to provide basis for pollution control of Hg in the bay. Results showed that, during 1979-1985, water in Jiaozhou Bay had been polluted by Hg in certain levels. For seasonal variation, there was a dicreasing trend form summer to winter in 1979, 1981 and 1985, and an increasing trend form summer to winter in 1980 and 1983. For annual variation, there was an obvious decreasing trend of Hg pollution from 1979-1982, while from 1982-1985 an increasing trend occurred. The temporal variation of Hg in Jiaozhou Bay reflects the conflict between economic growth and environmental protection. Having in mind that the environmental carrying capacity of Jiaozhou Bay is not unlimited, and the environmental disruption might finally cause economic loss and disasters to the human, we believe that the dischargd load of Hg should be limited in a suitable amount.

Abstract: This paper mainly studied the removal of Hg by biomass activated carbon in the simulated flue gas. Biomass activated carbon of different materials were made through the control of activator concentration, activation temperature in the self-developed biomass preparation system. In the fixed bed system, the flue gas Hg removal efficiency of activated carbon samples were evaluated. The experimental results showed that the adsorption performance of biomass activated carbon was not proportional with the change of the activator concentration and activation temperature, the overall trend was firstly increased and then decreased.

Abstract: Power sector is the major emitter in China of local air pollutants including SO2 and NOX, and CO2 and Hg with global environmental impacts. This study applied a bottom-up optimization model considering multi regional power grids in China to simulate how the local air pollution (LAP) control would shape the power generation mix before 2020 and estimate the mitigation potential of CO2 and Hg emission provided by LAP control. Results show that with LAP control targets, in 2020, 100% of coal-fired units need to be equipped with FGD or adopt in-furnace desulphurization for CFB; approximately 85% of coal-fired units should be equipped with SCR while the others retrofitted to be low NOX boilers. Compared to the scenario without environmental constraints, Hg emission decreases 46% while CO2 emission increases 0.64% in 2020 with LAP control targets. Control polices of local and global air pollutant emissions should be combined early in developing countries to obtain a cost-effective way for sustainable development.

Abstract: The fly ash was modified by Cl, Fe, Cu salts to investigate the mercury adsorption performance and analyze the impacts on it. Experiment results indicate that significant improvement of removal efficiencies with FeCl₃、CuCl₂ and CuBr₂ impregnation onto fly ash. The modification adjusted the pore structure of fly ash and formed more pores to absorb Hg, also it was found that new active sites were generated after the treatment, which can oxidize Hg⁰ and improve chemical adsorption.

Abstract: The paper researched the method of using the L-Cysteine to pre-reduction and using hydrid atomic fluorescence spectrometry to determining the As、 Sb 、Bi and Hg elements.In the preparation determination condition,the elements have a wide linear rangeand, the sample analysis results coincided with the recommended values. Detection limit of each element wereAs0.08ng／mL、Sb 0.06ng／mL、Bi 0.07ng／mL、Hg 0.004ng／mL。After nearly more than 100,000 pieces of the determination of geochemical samples, the sample have a good parallel.

Abstract: Samples of the superconducting ceramics Hg0.82Re0.18Ba2Ca2Cu3O8+ were prepared by solid-vapor reaction technique. The preparation of the ceramic precursor started with a mixture of Ba2Ca2Cu3Ox and ReO2 powders with molar ratio 1:0.18. The precursor material was submitted to annealing under three different partial pressures of oxygen using a mixture of oxygen/argon at ratios: 5/95 (sample A), 10/90 (sample B) and 15/85 (sample C). X-ray powder diffraction analysis of the precursors identified the phases BaCuO2+x, Ba2Cu3O5+x, Ba4CaCu3O8+x, Ca2CuO3 and Ca5Re2O12 at different ratios in the samples, indicating an increment in the oxygen content from sample A to sample C. Finally, the precursors with different oxygen contents were blended with HgO at molar ratio 1:0.82 and treated in a sealed high pressure furnace to produce the high Tc superconducting ceramics. Rietveld refinement of XRD data showed differences in the crystal structures of the samples. The measurement of thermopower at room temperature resulted in distinct values, confirming the different oxygen sample doping.