A novel carbon trap sampling system for gas-phase mercury measurement in flue gas is developed, including the high efficient sorbents made of modified biomass cokes and high precision sorbent traps for measuring parti...A novel carbon trap sampling system for gas-phase mercury measurement in flue gas is developed, including the high efficient sorbents made of modified biomass cokes and high precision sorbent traps for measuring particle-bound and total vapor-phase mercury in flue gas. A dedusting device is installed to collect fine fly ash for reducing the measurement errors. The thorough comparison test of mercury concentration in flue gas is conducted between the novel sampling system and the Ontario hydro method （OHM） in a 6 kW circulating fluidized bed combustor. Mercury mass balance rates of the OHM range from 95.47% to 104.72%. The mercury breakthrough rates for the second section of the sorbent trap are all below 2%. The relative deviations in the two test cases are in the range of 15. 96% to 17. 56% under different conditions. The verified data suggest that this novel carbon trap sampling system can meet the standards of quality assurance and quality control required by EPA Method 30B and can be applied to the coal-fired flue gas mercury sampling system.展开更多
To date, the Xunyang mercury(Hg) mining district is the only ongoing large-scale Hg mining district in China. To understand the influence of Hg contamination mode from the Hg mining and smelting activities, 27 samplin...To date, the Xunyang mercury(Hg) mining district is the only ongoing large-scale Hg mining district in China. To understand the influence of Hg contamination mode from the Hg mining and smelting activities, 27 sampling sites in the Xunyang Hg mining district were chosen in this study. Total gaseous mercury(TGM) in ambient air was measured using a Lumex-RA915 automatic Hg analyzer in2011. Rice samples and soil samples from rhizosphere were collected systematically and simultaneously. Total Hg(THg) and methylmercury(Me Hg) concentrations in rice grain and soil samples and Hg speciation with modified sequential selective extractions were measured. The local environment was seriously polluted with Hg. The TGM(302 ± 376 ng·m-3, ranging from 24 to 2220 ng·m^(-3)) in the local ambient air, THg(28 ± 30 mg·kg^(-1), ranging from 0.31 to 121 mg·kg^(-1)) and Me Hg(2.3 ± 1.9 lg·kg^(-1),ranging from 0.24 to 8.9 lg·kg^(-1)) in soil samples were at the sample level with Hg contaminated area. The THg concentration(26 ± 16 lg·kg^(-1)ranging from 4.5 to 71 lg·kg^(-1)) in most of the rice grain samples clearly exceeds the threshold level(20 lg·kg^(-1)) in the Chinese national guidelines for cereals(NY 861-2004). The inorganic mercury(IHg)(9.1 ± 5.6 lg·kg^(-1), ranging from 1.2 to 24 lg·kg^(-1)) and Me Hg(14 ± 9.8 lg·kg^(-1), ranging from 2.1 to 59 lg·kg^(-1))concentration in rice grain samples were at the same level with Hg contaminated area. The main species of Hg in paddy soils reveal strong complex Hg and residue Hg. According to the correlation analysis, a Hg pollution mode from local Hg mining and smelting was hypothesized, including Hg emission, transportation, methylation, and uptake process.展开更多
The soil-water retention curve(SWRC)can be used to evaluate the ability of unsaturated soils to attract water at various water contents and suctions. In this study, drying SWRCs for a kind of sandy soil were obtained ...The soil-water retention curve(SWRC)can be used to evaluate the ability of unsaturated soils to attract water at various water contents and suctions. In this study, drying SWRCs for a kind of sandy soil were obtained in the laboratory by using self-modified SWRC apparatus. In addition, the porosity and the pore size distribution of the samples were investigated by a mercury porosimetry test in order to analyze the effect of dry density. Results showed that the soil-water retention of the soil specimens was strongly dependent on the dry density. Under zero suction, soil specimens with a higher dry density exhibited lower initial volumetric water content. The higher the dry density of soil, the more slowly the volumetric water content decreased with the increase of suction. There was a general and consistent trend for a soil specimen to possess a larger air-entry value and residual suction, while smaller slope of SWRC when it had a higher density. This was probably attributed to the presence of smaller interconnected pores in the soil specimen with a higher dry density. The proportion of large diameter pores decreased in comparison to pores with small diameters in the soil tested. The measured total pore volume of the soil specimen, which had a larger dry density, was lower than that of the relatively loose specimens.展开更多
The graphene-gold nanoparticles composite film modified glassy carbon electrode （EG- AuNPs/GCE） was prepared by one-step coelectrodeposition and employed for determination of trace mercury in environmental water wit...The graphene-gold nanoparticles composite film modified glassy carbon electrode （EG- AuNPs/GCE） was prepared by one-step coelectrodeposition and employed for determination of trace mercury in environmental water with differential pulse stripping voltammetry. Such a nanostructured composite film combined with the advantages of gold nanoparticles and graphene, can greatly promote the electron-transfer process and increase accumulation abil-ity for Hg（Ⅱ）, leading to a remarkably improved sensitivity. The linear calibration curve ranged from 0.2 μg/L to 30 μg/L for Hg（Ⅱ） and the detection limit （S/N=3） was found to be 0.03 μg/L at a deposition time of 300 s. Moreover, the stablity of the as-prepared electrode and interferences from other substances were evaluated. The modified electrode was successfully applied to the direct detection of Hg（Ⅱ） in real water samples.展开更多
Ultrasonic aided slurry sampling hydride generation atomic fluorescence spectrometry （USS-HG-AFS） was developed for the determination of Hg in soil samples from a sewage-irrigated farm. 500 mg grounded soil was susp...Ultrasonic aided slurry sampling hydride generation atomic fluorescence spectrometry （USS-HG-AFS） was developed for the determination of Hg in soil samples from a sewage-irrigated farm. 500 mg grounded soil was suspended in agar solution by an ultrasound water bath before the HG-AFS determination. The results for the reference material of soil （serial number GBW-07411） agreed satisfactorily with the certified values. Results obtained by the developed procedure compared well with those after traditional acid digestion of samples. The detection limit are 6.7ngL-1 for Hg respectively, with average relative standard deviation values of 6.4% for analysis of a series of soil samples of different origin. The recoveries of the anatytes varied in the range from 95 to 107%. This observation has stimulated interest in fast, accurate and sensitive analytical methods for determination of metals in soil.展开更多
The study was undertaken to assess the extent of mercury contamination in the soil and three types of leaf plants in Campus AL-Mustansaryah University sites within Baghdad, Iraq, as well as to determine the relationsh...The study was undertaken to assess the extent of mercury contamination in the soil and three types of leaf plants in Campus AL-Mustansaryah University sites within Baghdad, Iraq, as well as to determine the relationship between environmental parameters and the distribution of the mercury contamination with carbon in soil samples were collected and analyzed for inorganic mercury. The highest mercury concentrations were recorded at the sites located lowest cover the plant and close to the diesel-electric generators. Mercury concentrations in leaf plant Ziziphusspina-christi higher concentration than the rest type and soil were mostly higher mercury concentration. Also ratio of carbon to coincide with the increase in the concentration of mercury in the soil of the study areas. Mercury is more biologically because of his preference to bind with carbon. This research confirms that Campus University is key areas for formation of bioavailable mercury distribution is tied to organic carbon.展开更多
In bilateral pbeochromocytoma, localization of the dominant adrenal is challenging but highly important since the removal of dominant side can markedly improve cardiovascular outcomes. To demonstrate the usefulness of...In bilateral pbeochromocytoma, localization of the dominant adrenal is challenging but highly important since the removal of dominant side can markedly improve cardiovascular outcomes. To demonstrate the usefulness of glucagon-stimulated BAVS （bilateral adrenal venous sampling） in determining the dominant adrenal to be removed, the authors reviewed records of patients who underwent BAVS with glucagon stimulation from 1997-2010. Nineteen out of 44 patients were diagnosed with bilateral pheochromocytoma. Mean age at diagnosis was 33 ± 14 years. Duration of hypertension was 5 ± 6 years with highest systolic BP （blood pressure） of 186 ±30 mmHg and diastolic BP of 113 ±18 mmHg. Headache （68%） is the most common symptom followed by paroxysmal hypertension （58%）. Majority were taking 〉 3 anti-hypertensive drugs. On glucagon-stimulated BAVS, 63% had right adrenal dominance. Three patients, who were hypertensive for 1, 6 and 12 years, underwent removal of the dominant adrenal. On follow-up （mean period = 36 months）, there was marked improvement in BP control [pre-op vs. post-op： （systolic） 160-240 mmHg vs. 120-150 mmHg; （diastolic） 90-110 mmHg vs. 70-90 mmHg] and reduction in number of anti-hypertensive medications （from 3-5 to 2 classes of drugs）. BAVS with glucagon stimulation is a valuable tool in the identification of the dominant adrenal to be removed in patients with bilateral pheochromocytoma to alleviate chronic hypertension.展开更多
基金The National Natural Science Foundation of China(No.51376046,51076030)the National Science and Technology Support Program of China(No.2012BAA02B01)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXZZ13_0093,KYLX_0115,KYLX_018)
文摘A novel carbon trap sampling system for gas-phase mercury measurement in flue gas is developed, including the high efficient sorbents made of modified biomass cokes and high precision sorbent traps for measuring particle-bound and total vapor-phase mercury in flue gas. A dedusting device is installed to collect fine fly ash for reducing the measurement errors. The thorough comparison test of mercury concentration in flue gas is conducted between the novel sampling system and the Ontario hydro method （OHM） in a 6 kW circulating fluidized bed combustor. Mercury mass balance rates of the OHM range from 95.47% to 104.72%. The mercury breakthrough rates for the second section of the sorbent trap are all below 2%. The relative deviations in the two test cases are in the range of 15. 96% to 17. 56% under different conditions. The verified data suggest that this novel carbon trap sampling system can meet the standards of quality assurance and quality control required by EPA Method 30B and can be applied to the coal-fired flue gas mercury sampling system.
基金financially supported by National Key Basic Research Program of China (973 Program,No.2013CB430004)the National Natural Science Foundation of China (No.41273152+1 种基金41473123)CAS Youth Innovation Promotion Association,Chinese Academy of Sciences (No.2011280)
文摘To date, the Xunyang mercury(Hg) mining district is the only ongoing large-scale Hg mining district in China. To understand the influence of Hg contamination mode from the Hg mining and smelting activities, 27 sampling sites in the Xunyang Hg mining district were chosen in this study. Total gaseous mercury(TGM) in ambient air was measured using a Lumex-RA915 automatic Hg analyzer in2011. Rice samples and soil samples from rhizosphere were collected systematically and simultaneously. Total Hg(THg) and methylmercury(Me Hg) concentrations in rice grain and soil samples and Hg speciation with modified sequential selective extractions were measured. The local environment was seriously polluted with Hg. The TGM(302 ± 376 ng·m-3, ranging from 24 to 2220 ng·m^(-3)) in the local ambient air, THg(28 ± 30 mg·kg^(-1), ranging from 0.31 to 121 mg·kg^(-1)) and Me Hg(2.3 ± 1.9 lg·kg^(-1),ranging from 0.24 to 8.9 lg·kg^(-1)) in soil samples were at the sample level with Hg contaminated area. The THg concentration(26 ± 16 lg·kg^(-1)ranging from 4.5 to 71 lg·kg^(-1)) in most of the rice grain samples clearly exceeds the threshold level(20 lg·kg^(-1)) in the Chinese national guidelines for cereals(NY 861-2004). The inorganic mercury(IHg)(9.1 ± 5.6 lg·kg^(-1), ranging from 1.2 to 24 lg·kg^(-1)) and Me Hg(14 ± 9.8 lg·kg^(-1), ranging from 2.1 to 59 lg·kg^(-1))concentration in rice grain samples were at the same level with Hg contaminated area. The main species of Hg in paddy soils reveal strong complex Hg and residue Hg. According to the correlation analysis, a Hg pollution mode from local Hg mining and smelting was hypothesized, including Hg emission, transportation, methylation, and uptake process.
基金Supported by the National Natural Science Foundation of China(No.51409261)
文摘The soil-water retention curve(SWRC)can be used to evaluate the ability of unsaturated soils to attract water at various water contents and suctions. In this study, drying SWRCs for a kind of sandy soil were obtained in the laboratory by using self-modified SWRC apparatus. In addition, the porosity and the pore size distribution of the samples were investigated by a mercury porosimetry test in order to analyze the effect of dry density. Results showed that the soil-water retention of the soil specimens was strongly dependent on the dry density. Under zero suction, soil specimens with a higher dry density exhibited lower initial volumetric water content. The higher the dry density of soil, the more slowly the volumetric water content decreased with the increase of suction. There was a general and consistent trend for a soil specimen to possess a larger air-entry value and residual suction, while smaller slope of SWRC when it had a higher density. This was probably attributed to the presence of smaller interconnected pores in the soil specimen with a higher dry density. The proportion of large diameter pores decreased in comparison to pores with small diameters in the soil tested. The measured total pore volume of the soil specimen, which had a larger dry density, was lower than that of the relatively loose specimens.
文摘The graphene-gold nanoparticles composite film modified glassy carbon electrode （EG- AuNPs/GCE） was prepared by one-step coelectrodeposition and employed for determination of trace mercury in environmental water with differential pulse stripping voltammetry. Such a nanostructured composite film combined with the advantages of gold nanoparticles and graphene, can greatly promote the electron-transfer process and increase accumulation abil-ity for Hg（Ⅱ）, leading to a remarkably improved sensitivity. The linear calibration curve ranged from 0.2 μg/L to 30 μg/L for Hg（Ⅱ） and the detection limit （S/N=3） was found to be 0.03 μg/L at a deposition time of 300 s. Moreover, the stablity of the as-prepared electrode and interferences from other substances were evaluated. The modified electrode was successfully applied to the direct detection of Hg（Ⅱ） in real water samples.
文摘Ultrasonic aided slurry sampling hydride generation atomic fluorescence spectrometry （USS-HG-AFS） was developed for the determination of Hg in soil samples from a sewage-irrigated farm. 500 mg grounded soil was suspended in agar solution by an ultrasound water bath before the HG-AFS determination. The results for the reference material of soil （serial number GBW-07411） agreed satisfactorily with the certified values. Results obtained by the developed procedure compared well with those after traditional acid digestion of samples. The detection limit are 6.7ngL-1 for Hg respectively, with average relative standard deviation values of 6.4% for analysis of a series of soil samples of different origin. The recoveries of the anatytes varied in the range from 95 to 107%. This observation has stimulated interest in fast, accurate and sensitive analytical methods for determination of metals in soil.
文摘The study was undertaken to assess the extent of mercury contamination in the soil and three types of leaf plants in Campus AL-Mustansaryah University sites within Baghdad, Iraq, as well as to determine the relationship between environmental parameters and the distribution of the mercury contamination with carbon in soil samples were collected and analyzed for inorganic mercury. The highest mercury concentrations were recorded at the sites located lowest cover the plant and close to the diesel-electric generators. Mercury concentrations in leaf plant Ziziphusspina-christi higher concentration than the rest type and soil were mostly higher mercury concentration. Also ratio of carbon to coincide with the increase in the concentration of mercury in the soil of the study areas. Mercury is more biologically because of his preference to bind with carbon. This research confirms that Campus University is key areas for formation of bioavailable mercury distribution is tied to organic carbon.
文摘In bilateral pbeochromocytoma, localization of the dominant adrenal is challenging but highly important since the removal of dominant side can markedly improve cardiovascular outcomes. To demonstrate the usefulness of glucagon-stimulated BAVS （bilateral adrenal venous sampling） in determining the dominant adrenal to be removed, the authors reviewed records of patients who underwent BAVS with glucagon stimulation from 1997-2010. Nineteen out of 44 patients were diagnosed with bilateral pheochromocytoma. Mean age at diagnosis was 33 ± 14 years. Duration of hypertension was 5 ± 6 years with highest systolic BP （blood pressure） of 186 ±30 mmHg and diastolic BP of 113 ±18 mmHg. Headache （68%） is the most common symptom followed by paroxysmal hypertension （58%）. Majority were taking 〉 3 anti-hypertensive drugs. On glucagon-stimulated BAVS, 63% had right adrenal dominance. Three patients, who were hypertensive for 1, 6 and 12 years, underwent removal of the dominant adrenal. On follow-up （mean period = 36 months）, there was marked improvement in BP control [pre-op vs. post-op： （systolic） 160-240 mmHg vs. 120-150 mmHg; （diastolic） 90-110 mmHg vs. 70-90 mmHg] and reduction in number of anti-hypertensive medications （from 3-5 to 2 classes of drugs）. BAVS with glucagon stimulation is a valuable tool in the identification of the dominant adrenal to be removed in patients with bilateral pheochromocytoma to alleviate chronic hypertension.
