Adsorption of phenanthrene and pyrene by biochar produced from the excess sludge: experimental studies and theoretical analysis     

W. Guo  Y. Ai  B. Men  S. Wang 《International Journal of Environmental Science and Technology》2017,14(9):1889-1896

A biochar derived from the pyrolysis of excess sludge of sewage treatment plant at 700 °C was used to remove phenanthrene and pyrene from aqueous solution. The adsorption equilibrium for phenanthrene and pyrene was achieved within 7.5 and 15 h, respectively. The adsorption kinetics of phenanthrene and pyrene were well fitted to pseudo-second-order model, and the isotherms were well fitted to Freundlich adsorption isotherm model (R ² > 0.96). The effect of variation of pH on the adsorption of the biochar was observed to be insignificant. The hydrophobic action and pore filling might be the main mechanisms of the adsorption of phenanthrene and pyrene on the biochar. The density functional theory calculations confirmed that the adsorption depended mainly on the biochar structure and the molecular volumes of phenanthrene and pyrene. Phenanthrene molecule is smaller than the pyrene molecule and therefore showed better adsorption characteristics with the biochar than the pyrene molecule.  相似文献   

柴达木盆地北缘沉积凝灰质岩层段的地层时代   总被引：2，自引：0，他引：2  

门相勇  李伟  席萍  唐伦和 《地质科学》2001,36(2):229-233

柴达木盆地北缘深部沉积凝灰质岩层段的地层归属存在2种观点,下侏罗统和石炭系。本文通过岩石薄片、微量元素、孢粉组合以及海相化石碎片等多种资料的综合分析,认为沉积凝灰质岩层段与其上的下侏罗统之间岩性、电性出现突变的主要原因是沉积时火山事件以及晚期方解石脉充填造成的,并不能代表下伏的老地层;沉积凝灰质岩层段的海相化石碎片为搬运再沉积的结果,没有地层指示意义;孢粉组合能反映沉积凝灰质岩层段沉积的地质年代,据此确认沉积凝灰质岩层段为下侏罗统湖西山组二段。  相似文献   

Investigation of earthquake mechanisms and their impact on certain basic concepts in earthquake engineering and seismology     

Fulu Men 《地震工程与工程振动(英文版)》2002,1(2):281-291

In this paper, mantle circulation flow, continental drift, earthquake origin and other mechanical principles are examined as they apply to earthquake engineering, seismology and dynamics of fluid saturated porous medium. The relationship of mantle flow to earthquakes is examined and clarified, and a new model, different from Haskell’s, is proposed for the earthquake mechanism. The proposed new model is based on the discovery that two pairs of jump stress and jump velocity will start to act from the fault plane. Records obtained directly from recent earthquakes nearby and right on the fault break show a very large velocity impulse, which verify, indirectly, the new mechanism proposed by the author. Further, at least two physical parameters that characterize the seismic intensity must be specified, because according to the discontinuous (jump) wave theory, at the earthquake source, the stress jump and the velocity jump of particle motion should act simultaneously when a sudden break occurs. The third key parameter is shown to be the break (fracture) propagation speed together with the break plane area. This parameter influences the form of the unloading time function at the source. The maximum seismic stress in and displacement of a building are estimated for two unfavorable combinations of the building and its base ground in terms of their relative rigidity. Finally, it is shown that Biot’s theory of wave propagation in fluid saturated porous media is valid only when fluid flow cannot occur.  相似文献   

Distribution and Variation of Ribonucleic Acid （RNA） and Protein and Its Hydrolysis Products in Lake Sediments     

梁小兵  万国江  黄荣贵 《中国地球化学学报》2002,21(2):175-185

Protein and RNA in lake sediments tend to be decomposed progressively with time and sedimentation depth. Their concentrations tend to decrease starting from the sedimentation depth of 17 cm and that of 19 cm, respectively. However, the products of their decomposition —amino acids and nucleotides show different rules of variation. At the depth from 27 cm to 30 cm the amino acids are most abundant in the pore waters of lake sediments. Such variation tendency seems to be related to the extent to which microbes utilize amino acids and nucleotides. Due to polymerization in the geological processes and the adsorption of protein on minerals and organic polymers, below the sedimentation depth of 17 cm there is still a certain amount of protein in the sediments. With the time passing by, protein has been well preserved in various sediment layers, indicating that its decomposition is relatively limited. The peak values of protein content in the sediments of the two lakes are produced in the surface layers at the depth of 10 cm, implicating that the surface sediments are favorable to the release of protein. The contents of amino acids in the pore waters of lake sediments are closely related to the activities of microbes. Below the depth of 27 cm, the amino acids are significantly accumulated in Lake Aha sediments, probably indicating the weakening of microbial activities. The research project was financially supported jointly by the Ntional Natural Science Foundation of China (No. 40173038) and the Guizhou Provincial Foundation (No. 3090) and the Chinese Academy of Sciences Knowledge-Innovation Foundation (KZCX2-105).  相似文献   

以剪切波速为宗量的一种砂土地震液化的不确定性判别法   总被引：6，自引：0，他引：6  

崔杰  沈世杰 《地震工程与工程振动》1997,17(3):91-99

利用基于剪切波速的砂土液化判别法，本文提出了一种可考虑剪切波速的随机性和液化及液化危害等级的模糊性的液化和液化危害等级的判别法。作者首先讨论了当剪切波速具有随机性时液化的发生概率，进而给出了确定场地液化和危害程度的发生概率。在此基础上，结合液化和液化危害程度（等级）的模糊性，利用模糊事件的概率分析方法，提出了可同时考虑随机性和模糊性的场地液化和液化危害性的发生概率的计算方法。  相似文献   

江苏-南黄海地区M≥6强震预测探索     

门可佩 《地震地磁观测与研究》1993,(2)

江苏-南黄海地区自16世纪以来已发生17次6级以上强震,经研究发现它们存在着时间间隔为74年、57年、26年、7年的有序性结构,利用这种强震活动的有序性和可公度性理论相结合,试对该区6级以上强震进行预测探索,结论是1995-1996年、2001-2002年前后该区有发生6级以上强震的可能。  相似文献   

新疆及其邻区M≥7强震的预测研究   总被引：2，自引：0，他引：2       下载免费PDF全文

门可佩 《地震工程学报》1994,16(4):29-36

新疆及其邻近地区Ｍ≥７强震活动在时间分布上具有明显的有序性。自１７１６年以来的２１次Ｍ≥７强震存在着时间间隔为１１、２５、３０、４１和６０年的有序值。利用强震活动时间的有序性结构，可对该区７级强震进行预测探索。本文同时还应用熵和经验分布函数，讨论了下次强震发生的地点和概率。  相似文献   

阴山东段先寒武变质岩的Rb-Sr年代          下载免费PDF全文

孙荣圭  Richard Lee Armstrong  孙大中  韩光 《地质科学》1987,(3):258-264

采自阴山东段先寒武变质岩的全岩样品给出四个等时线年龄。下部集宁群为2497±124Ma;上部乌拉山群为2367±127Ma;上部二道洼群给出两个年龄:2067±39Ma和325±16Ma。据此认为,2.5Ga前发生了麻粒岩化;2.35Ga前发生混合岩化;2.0Ga和0.33Ga前有变质事件叠加。  相似文献   

扬子鳄的人工养殖与气象条件的关系   总被引：5，自引：0，他引：5       下载免费PDF全文

华荣贵  曹树新  蒋宣清  汪仁平 《气象》1995,21(3):51-54

对人工养殖扬子鳄的气象条件及扬子鳄的生活习性与天气条件的关系进行了分析。结果表明，温度、湿度是影响幼鳄成活率和生长发育的关键因子；天气则在很大程度上影响扬子鳄的生活习性。指出了扬子鳄生长期及活动期的适宜气象条件，这对提高扬子鳄的人工繁殖率和幼鳄饲养成活率有关积极作用。  相似文献   

2006年1月宝鸡强降雪过程综合分析          下载免费PDF全文

郭清厉  孟妙志  陈卫东 《陕西气象》2006,(6):30-32

2006-01-17T 08—20T 08,宝鸡出现了一次中到大雪天气过程,18日08时到19日08时扶风降雪量达18.9 mm,为历史少见。通过环流背景和物理量场分析表明:低空急流输送丰沛水汽,东路冷空气南下与暖湿气流在河套交汇,造成这次强降雪;低空东风急流形成,使低层水汽输送增强,辐合加大,辐合层加厚,是降雪增大的关键。在卫星云图上,云顶亮温tBB为-10oC左右的低云稳定少动,对应降雪持续,当tBB<-60oC的高空对流云移经宝鸡时,降雪增强。  相似文献