The characteristics of mercury desorption on spent CeO2-TiO2 (CeTi) sorbents were investigated to improve the cyclic regeneration removal activity. Mercury was significantly released in the form of elemental mercury at temperatures ranging from 250 to 280 °C. Mercury desorption had a significant correlation with regeneration temperature, but was independent of the heating rate and regeneration conditions. The optimal regeneration temperature was 500 °C. The CeTi sorbents could be easily restored by simple heating and exhibited superior activity over several capture- regeneration cycles. The amount of released mercury almost equaled the adsorbed mercury on the surface of the CeTi sorbent, indicating that most of the adsorbed mercury was released during the heating process.

建立了金属氧化物吸附剂CeO2(111)表面的结构模型,首先计算了H2S、HS、S在CeO2(111)表面吸附的结合能及键长,结果表明H2S会在CeO2(111)表面依次分解为HS与单质S;随后计算了Hg在S-CeO2(111)表面吸附的结合能及键长,结果表明Hg会与CeO2(111)表面的单质S结合成键形成稳定的HgS,结合能为-52.829 eV,属于强烈的化学吸附,从微观上发现了H2S的存在对单质汞在CeO2表面的吸附有促进作用.

CeO2 was doped into Pd/Al2O3 using an impregnation method to suppress the interference of H2S and to improve the ability to capture elemental mercury (Hg-0) from syngas at high temperatures. As a result, the Hg-0 capture performance was generally enhanced by the incorporation of Ce as a result of the consumption of H2S. The individual presence of H-2 or CO resulted in the formation of Pd metal responsible for Hg-0 capture and active ceria in reduced form for H2S removal, thus promoting the Hg-0 removal. Meanwhile, H2S could react with CO to form COS, which competed with Hg-0 for active sites, hence inhibiting Hg-0 capture. The effect of HCl on Hg-0 capture over PCA sorbents was found to be slightly promotional, because a small amount of Hg-0 was oxidized to HgCl2. More importantly, the spent PCA sorbents could be easily reactivated, indicating that this material is a prospective candidate for Hg-0 control from syngas.

To capture elemental mercury (Hg0) at high temperatures in simulated syngas, Pd/Al2O3 sorbents were developed using an impregnation method. The Pd/Al2O3 sorbents with a Pd loading value of 8% exhibited high Hg0 capture activity from 200 to 270 °C. Over 90% of the mercury capture by 8Pd/Al2O3 was achieved for operating temperatures up to 270 °C. The superior performance of Pd/Al2O3 sorbents could be primarily ascribed to the formation of a Pd–Hg amalgam. H2 and CO were found to be promotional on Hg0 capture because of the reduction of PdO to Pd metal. H2S significantly inhibited Hg0 capture due to the consumption of the active palladium. HCl promoted Hg0 capture, which could be ascribed to the catalytic oxidation of Hg0 to HgCl2. H2O showed a prohibitive effect on Hg0 removal. The regeneration experiments indicated that the spent Pd/Al2O3 sorbents could be facilely revivified and reused.

Valtrate is a principle compound isolated from Valeriana jatamansi Jones, which is a Traditional Chinese Medicine used to treat various mood disorders. The aim of the present study was to investigate the anxiolytic effects of valtrate in rats. The animals were orally administered valtrate (5, 10, and 20 g/kg daily) for 10 days and exposed to open field test (OFT) and elevated plus-maze (EPM). Then the corticosterone levels in the rat serum were measured by enzyme-linked immunosorbent assay (ELISA). The valtrate (10 mg/kg, p.o.) exhibited the anxiolytic effect in rats by increasing the time and entry percentage into the open arms in the EPM and the number of central entries in the OFT. Valtrate (10 mg/kg, p.o.) significantly reduced the corticosterone level in the rat serum. Taken together, these results suggest that the valtrate has anxiolytic activity in behavioral models that might be mediated via the function of hypothalamus-pituitary-adrenal axis.

Activated coke modified with manganese acetate ( Mn-AC ) was prepared through inciip ent imrp egan tiona nd hc aracterized by nitrogen sorption, X-ray photoelecuon spectroscopy ( XPS ) and X-ray diffractoi n ( XRD) .Mn-AC was used as a sorbent in the removal of eleme nat l mercury in a simual ted syngas (0.04%H2 S, 20% CO, 30%H 2 and balanced N2 ) and the various actors influne cing the removal efficiency were investigated in a bench-scale fixed-bed reactor.The results indicated that Mn-AC exhibits excellent Hg0 removal capacity at 200℃and 84.3%of Hg0 can be removed from the syngas.H2 S present in the syngas can obviously promote the Hg0 removal efficiency at high temperature, as H2S is oxidized to elemental sulfur (Sad) that provides active adsorption sites for Hg0 to form HgS.Both H2 and CO are unfavorable to mercury removal, as H2 may deplete the actiev oxygne in the sorbent surface and CO may react with the active sulfur sites ( forming COS) .At high temperature, mercury remo val is suppressed, which may be attributed to that the interaction between Hg0 and active sulfur sites is weakened and reducing capacity of H2 is strengthened, resulting in the decrease of the active sites for mercury adsorptoi n.

CeTi sorbent (CeO2 supported on TiO2) was employed to remove elemental mercury (Hg-0) from syngas when H2S and/or HCl are present. CeTi sorbents exhibited higher Hg-0 removal efficiency compared with S-impregnated activated carbon. H2S and HCl were the most effective syngas components responsible for Hg-0 removal when they were employed separately. When 400 ppm H2S and 10 ppm HCl were introduced separately with a balance of dry N-2, over 97% of the Hg-0 was removed under the experimental conditions. However, the combination of H2S and HCl exerted a prohibitive effect on Hg-0 removal, which could be attributed to two causes: (1) the HCl consumed the surface oxygen active for Hg-0 removal, hence limiting Hg-0 removal by H2S; and (2) the H2S competed with Hg-0 for active adsorption sites, limiting the Hg-0 removal by HCl. On the basis of the temperature-programmed decomposition (TPD) analysis and X-ray photoelectron spectroscopy (XPS) characterization of the sorbents, a Hg-0 removal mechanism in the presence of H2S over CeTi sorbents was proposed, suggesting that surface oxygen on the of CeTi sorbent supported the transformation of H2S to active surface sulfur, through which Hg-0 could be captured resulting in the formation of HgS. (C) 2013 Elsevier B.V. All rights reserved.

This study was aimed to establish an HPLC method for simultaneous content determination of valtrate, acevaltrate, and their degradation products, which were baldrinal and 11-ethoxyviburtinal, in Valeriana jatamansi Jones. The separation and quantification of 4 constituents mentioned above were performed on an Agilent ZORBAX SB-C18 (4.6 mm×250 mm, 5 μm). The mobile phase consisted of water (A) - acetonitrile (B) with an optimized gradient program. The flow rate was 1 mL·min-1. The column temperature was set at 25℃. The wavelength was set at 241 nm. And the injection volume was 10μL. The results showed that among 14 different places of V. jatamansi, the 4 contents determined were different. The contents of valtrate, acevaltrate, and baldrinal in the Yunnan Baoshan Mount were the highest. And the content of 11-ethoxyviburtinal was the highest in Yunnan Dali. It was concluded that the method was with good precision, reproducibility and stability. And it was suitable for the determination of 4 valepotriates ingredients in V. jatamansi. It also provided references for the quality control and exploitation of V. jatamansi.

在小型热态循环流化床试验台上进行褐煤、烟煤、无烟煤燃烧试验,研究3种典型煤的烟气气态汞和飞灰颗粒汞迁移规律.试验结果表明:褐煤、烟煤、无烟煤在燃烧过程中,炉膛温度、空截面风速、给煤量以及煤颗粒大小变化时,汞元素在烟气和飞灰之间的迁移规律相似;降低炉膛密相区温度和增大炉膛空截面风速可促进烟气气态总汞HgT(g)迁移到飞灰颗粒汞Hg(p)中,同时也促进烟气气态零价汞Hg0(g)向烟气气态二价汞Hg2+(g)和Hg(p)转化;增加给煤量,烟气气态总汞HgT(g)和烟气气态零价汞Hg0(g)减少,飞灰颗粒汞Hg(p)含量增加,并且影响Hg0(g)的转化;选择合适的煤颗粒粒度可以促进Hg0(g)的转化以及HgT(g)向Hg(p)迁移.随燃烧工况的变化,3种煤HgT(g)、Hg(p)和Hg0(g)含量变化趋势相似,但含量相差较大,Hg0(g)占HgT(g)的比例y值也不同,其中无烟煤的y值高于烟煤和褐煤的y值.

Fe2O3 sorbents synthesized by ultrasonic-assisted precipitation method were employed to remove elemental mercury (Hg0) in coal gas. The samples were characterized by low-temperature nitrogen adsorption , scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. Performance and mechanism of removing mercury by Fe2O3 were studied under simulated coal gas using a fixed-bed reactor. The experimental results show that the adsorption performance of Fe2O3 is relatively poor in nitrogen atmosphere,and physical adsorption dominates the mercury capture; Fe2O3 sorbents exhibit high Hg0removal activity when 400 × 10?6 H2S was introduced, more than 98% of Hg0 was removed at 150 ℃; H2S concentration affects Hg0 removal efficiency in the initial stage of reaction, but the effect decreases as the reaction proceeds. In the presence of H2S,Hg0 removal by Fe2O3 follows the Eley-Rideal mechanism, where adsorbed S(ad) reacts with gas-phase Hg0.

Sweet sorghum (Sorghum bicolor (L.) Moench) is a promising energy crop for biofuel production. A demonstration study on cost-effective conversion of fermentable sugars in sweet sorghum stems into ethanol with advanced solid-state fermentation technology is presented in this paper. A continuous solid-state fermenter, which is 55m in length and 3.6m in diameter, is successfully operated in Inner Mongolia, China in 2011. Results show that the retention time (fermentation time) of the solid substrate is less than 30h, and the ethanol yield reaches 90.5% of the theoretical yield. A total of 16ton of sweet sorghum stems (with 13.5% sugar content and 70% moisture) are used to produce 1ton of ethanol (99.5%, v/v). The cost of fuel ethanol production is $615.4per ton (49cent/liter) on the premise that the price of the sweet sorghum stems is $30per ton.

A series of CeO2-TiO2 (CeTi) sorbents with different CeO2/TiO2 mass ratios were prepared by an impregnation method and employed to remove elemental mercury (Hg(0)) in simulated syngas. The CeTi sorbents with a CeO2/TiO2 mass ratio of 0.2 exhibited superior Hg(0) removal efficiency from 80 to 150 °C, which could be ascribed to the greater amount of surface chemisorbed oxygen resulted from Ce(3+) on the sample surface. H2S was the most effective syngas component responsible for Hg(0) removal. The use of 400 ppm H2S resulted in 98% Hg(0) removal efficiency under the experimental conditions. H2 and CO had a negligible effect on the efficiency of Hg removal. In the presence of H2S, a prohibitive effect of HCl and NH3 on Hg(0) removal was observed because of the consumption of the surface oxygen. Water vapor also inhibited Hg(0) removal due to competitive adsorption with H2S. Hg(0) removal over CeTi sorbents was proposed to follow the Eley-Rideal mechanism, in which active surface sulfur reacts with gas-phase Hg(0). This large oxygen storage capacity of CeTi sorbents is quite favorable to H2S catalytic oxidation and Hg(0) emission control in an extremely reducing environment, such as when there is a deficiency of O2.

The adsorption of gas-phase elemental mercury by iron oxide sorbent under nitrogen and simulated gas atmosphere was studied on a bench-scale fixed-bed apparatus by using mercury online analyzer.The result showed that,the calcination of the iron oxide sorbent suppressed the removal of the mercury under N2 atmosphere.The iron oxide sorbent had a high mercury removal efficiency under H2S atmosphere and the mercury removal efficiency can be maintained above 90% for a long time.The elemental mercury removal efficiency was influenced strongly by the adsorption temperature.With the adsorption temperature increased,the elemental mercury removal efficiency varied in the shape of a mountain.

A systematic method for the estimation of stability of valtrate was established.HPLC-electrospray tandem mass spectrometry(HPLC-ESI MS/MS) was applied to separate the degradation products of valtrate and identify structures of the main degradation products.The samples were separated on an Agilent Extend-C18 by gradient elution using acetonitrile-0.25% acetic acid as mobile phase and analyzed under positive ion mode.Four degradation products were identified with the parent nucleus structures of baldrinals-compounds,in which one of oxidation products was identified through the reference substance.An HPLC method was established for the determination of the content change of valtrate in H2O2 at different time points.The result indicated that the content change of valtrate in H2O2 fits the first order kinetic equation,and the degradation of 10% prototype product occurred in 0.5 h.This paper revealed the degradation mechanism and degradation rule of valtrate from two aspects of both qualitative and quantitative analysis,and provided a theoretical basis for further research.

The adsorption of gas-phase elemental mercury by iron oxide adsorbent synthesized by an ultrasonic-assisted precipitation method under nitrogen and simulated gas atmosphere was studied on a bench-scale fixed-bed apparatus by using mercury online analyzer. And the effect of various gases on Hg0 removal performance by iron oxide adsorbent was analyzed. The result showed that the mercury removal efficiency of iron oxide adsorbent is low under N2 atmosphere. H2S promotes the Hg0 removal by iron oxide adsorbent. The iron oxide adsorbent has a high mercury removal efficiency under H2S atmosphere and the mercury removal efficiency can be maintained above 90%for a long time. The effects of CO and H2 were not observed at 150,℃. H2O suppressed the mercury removal at 150,℃. With the increase of adsorption temperature,the elemental mercury removal efficiency increases first and then gradually de-creases.

Aim To study the antidepressive effects of 1-methylhydantoin on rats and to investigate the related mechanisms.Methods The rat model of depression was established by chronic forced swim stress.Fluoxetine(10 mg·kg-1·d-1)and 1-methylhydantoin(20,40 and 80 mg·kg-1·d-1) were administered after stress procedure for 14 days.Body weights were measured and depression-like behaviors were evaluated in the open-field test and sucrose preference test.Then the corticosterone levels in the rat plasma were determined by enzyme-linked immunosorbent assay(ELISA) and BDNF protein levels in the hippocampus were measured by western blotting analysis.Results Compared with control group,chronic forced swim stress caused significant decreases of body weight,total distances and BDNF levels,and a significant increase of the corticosterone level in the rat plasma.Compared with the model group,1-methylhydantoin(40 mg·kg-1) could significantly improve body weight,total distances and BDNF levels in rats and reduce the corticosterone level in the rat plasma.Conclusion The results suggest that the antidepressive effects of 1-methylhydantoin is likely to be mediated by modulating the function of HPA axis and increasing the expression of BDNF in brain tissues.

OBJECTIVETo discuss mass spectrum characterization of five valepotriates including 'monoene' type (didrovaltrate), 'diene' type (valtrate, acevaltrate) and 'four-olefinic' type (baldrinal and homobaldrinal) by electrospray ionization tandem mass spectrometry (ESI-MS(n)).METHODThis study was carried out on the basis of electrospray ionization tandem mass spectrometric method and analysis of multistage fragments.RESULTThe fragmentation patterns and structural assignment of 'monoene' type, 'diene' type and 'four-olefinic' type valepotriates in ESI-MSn under positive mode were summarized.CONCLUSIONThe compounds have a strong pyrolysis rules and it can provide reference date for valepotriates in rapid structural identification, quantitative analysis and pharmacokinetic study.

Nano-ZnO sorbents synthesized by a homogeneous precipitation method were characterized by BET (Brunauer-Emmett-Teller), XRD (X-ray diffraction) as well as XPS (X-ray photoelectron spectroscopy) analysis. The adsorption of elemental mercury by nano-ZnO under nitrogen and simulated gas atmosphere was studied on a bench-scale fixed-bed apparatus. The effect of various gases on Hg0 removal performance by nano-ZnO was analyzed. The results show that the mercury removal efficiency of the nano-ZnO is relatively poor in nitrogen atmosphere. The presence of H2S promotes the Hg0 removal by nano-ZnO observably and the mercury removal efficiency can be maintained for a long time even after stopping pass into H2S. The presence of CO and H2 promote the Hg0 removal by promotion of nano-ZnO desulfurization. As the temperature increases, the formation of elemental sulfur in the surface of the nano-ZnO gradually reduces, leading to suppress the removal of Hg0.

目的:对缬草素(valtrate)和异缬草素(isovaltrate)在电喷雾质谱下的裂解途径进行探讨.方法:采用高效液相色谱-电喷雾离子阱质谱对样品进行系统研究,正离子模式下进行检测,毛细管电压为3.5 kV.液相色谱条件:色谱柱为AgilentXDB-C18柱(50 mm ×4.6 mm,5μm),流动相为水-乙腈(32∶68),流速1 mL·min-1.结果:缬草素和异缬草素在正离子模式下,8,10位环氧结构均存在2种裂解途经:一是环氧基团(CH2O)丢失,二是环氧基团异构化形成醛基结构;此外,由于11位取代基及7位酯基所处空间效应和诱导效应的不同使缬草素和异缬草素在正离子模式下会形成不同的特征碎片离子,如缬草素会形成m/z为219和m/z 415的特征碎片,而异缬草素会出现m/z 261和m/z 385的特征碎片.结论:该质谱检测方法可以区分同分异构体缬草素和异缬草素,并为含有环氧结构的这类环烯醚萜化合物的快速鉴定提供参考.

Previous articleNext article No AccessArticlesReflections on Chinese Traditional Ideas of NatureWenhui HouWenhui Hou Qingdao University, Shandong Province, People's Republic of China Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmailPrint SectionsMoreDetailsFiguresReferencesCited by Volume 2, Number 4October 1997 Published for the American Society for Environmental History and the Forest History Society Views: 66Total views on this site Article DOIhttps://doi.org/10.2307/3985610 Views: 66Total views on this site © 1997 American Society for Environmental History and Forest History SocietyPDF download Crossref reports no articles citing this article.