应用生烃动力学法研究川东上二叠统烃源岩生烃史   总被引：3，自引：2，他引：1  

徐立恒  陈践发  卢双舫  马广宇  李吉君 《吉林大学学报(地球科学版)》2008,38(4)

现今川东上二叠统烃源岩生烃史研究具有局限性.首先,没有对上二叠统Ⅰ-Ⅱ1型灰岩生油、Ⅲ型泥岩的生气史分开评价;其次,海相镜质组反射率通过拟合公式换算成镜质体反射率评价烃源岩成熟度具有局限性.针对上述不足,笔者通过热模拟实验,利用化学动力学方法,标定出两类源岩生油、生气的动力学参数,并结合川东地区的埋藏史及热史,模拟出源岩有机质的成烃转化率曲线.研究表明:上二叠统灰岩、泥岩有机质在距今200 Ma和190 Ma分别进入了生油、生气门限,而在距今170 Ma和140 Ma生烃结束.  相似文献   

菲降解菌的降解特性及酶促反应动力学研究     

席宏波  杨琦  尚海涛  郝春博 《地学前缘》2008,15(6)

通过对取自MBR膜生物反应器中的活性污泥加入菲进行富集培养、驯化,分离、纯化出一株能以菲为唯一碳源和能源的短杆状革兰氏阴性菌J-1,细菌长2～5μm,宽1～3μm;研究了初始底物浓度、温度、pH对菌株J-1降解菲的影响,探讨了菌株J-1胞内酶对菲降解的底物抑制动力学。试验表明:菌株J-1在48h内能将不同浓度菲的水溶液中的菲完全降解;菲浓度增加,达到完全降解的时间延长。温度对细菌的降解能力影响较大,菌株J-1对菲降解的最佳温度为28℃。1.15mg·L-1的菲,28℃时48h内能完全降解,而相同时间内10℃时的降解率仅为36.65%。菌株J-1对pH的波动具有一定的适应性,pH在一定范围内(6.0～8.4)变化对菲降解的影响不大,降解反应的最佳pH为7.2。菌株J-1对菲的降解符合一级动力学反应方程。较高的底物浓度对酶促降解反应具有抑制作用,酶促反应的最大速率常数vm=1.17mg·L-1·h-1,米氏常数Km=61.70mg·L-1;底物抑制常数kS=49.60mg·L-1;最佳底物浓度[S]opt=55.32mg·L-1。  相似文献   

Kinetics of redox cycling of iron coupled with fulvic acid     

Yiwei Deng  Werner Stumm 《Aquatic Sciences - Research Across Boundaries》1993,55(2):103-111

The kinetics of conversion of iron(III) (hydr)oxides to ferrous iron mediated by fulvic acid have been investigated in order to improve the understanding of the redox cycling of iron at the oxic-anoxic boundary in natural waters. Under the conditions similar to natural waters, fulvic acid is able to reduce the iron(III) (hydr)oxide. The kinetics of the reaction depend on the reactivity of iron(III) (hydr)oxides and the reducing power of the fulvic acid. The rate of reaction is 60 nm/h obtained under following conditions: total concentration of Fe(III) 1.0 × 10^–4 M, pH 7.5, fulvic acid 5 mg/L. The rate is considered as a net result of reduction and oxidation in the > Fe^III-OH/Fe(II) wheel coupled with fulvic acid. In a real natural water system, reductants other than fulvic acid may be of importance. The results obtained in the laboratory, however, provide evidence that the Fe(OH)₃(s)/Fe(II) redox couple is able to act as an electron-transfer mediator for the oxidation of natural organic substances, such as fulvic acid by molecular oxygen either in the absence of microorganisms or as a supplement to microbial activity.  相似文献   

Brønsted reactions on oxide mineral surfaces and the temperature-dependence of their dissolution rates     

William H. Casey  Marcus A. Cheney 《Aquatic Sciences - Research Across Boundaries》1993,55(4):304-313

The pH-dependence of oxide dissolution rates is controlled by Brønsted acid-base reactions at the mineral surface. These reactions are rapid but depend explicitly on temperature, as do the subsequent slow rates of bond hydrolysis. The net result is that dissolution rates vary in a complicated fashion with temperature and solution pH. The enthalpy changes of acid-base reactions on oxide materials are sufficiently similar, however, that general statements can be made about their contribution. The enthalpy changes from proton adsorption to a hydroxyl functional group (SOH), or to a deprotonated functional group (SO ^–), are generally exothermic. The enthalpy changes become increasingly endothermic, however, as charge accumulates on the mineral surface and the charged species interact electrostatically. The result is that mineral dissolution rates are least sensitive to temperature, as measured with an Arrhenius-like rate law, at pH conditions near the Point of Zero Net Proton Charge.  相似文献   

A continuous and mechanistic representation of calcite reaction-controlled kinetics in dilute solutions at 25°C and 1 atm total pressure     

Takeshi Arakaki  Alfonso Mucci 《Aquatic Geochemistry》1995,1(1):105-130

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Acid leaching of ash and coal: Time dependence and trace element occurrences     

Mehtap Paul  Meryem Seferinoğlu  Gul Asiye Ayçık  Åke Sandström  Michael L. Smith  Jan Paul 《International Journal of Mineral Processing》2006

The leaching of coal and coal/asphaltite/wood-ashes in sulfuric acid (pH 1.0, 25 °C, S/L, 1:10) was studied as a function of time; acid consumption and extracted metal concentrations are presented. Whole coals consumed acid rapidly during the first few minutes, followed by slow acid consumption. Wood-, lignite-, and asphaltite-ashes consumed acid in two stages, the rapid phase extending < 30 min and the slow phase extended up to 10 days. The rapid phase was dominated by the dissolution of Ca, K and Mg ions for wood-ash, by Ca, Al and Mg ions for lignite-ash and Ca and Mg ions for asphaltite-ash. The sulfur concentration in solution and the concentrations of Ca, Fe, K, Mg, Na, P, Al and Mn in the aqueous phase verified the neutralizing capacity of the untreated ashes as well as the formation of insoluble sulfates in the residues. The slow phase kinetics differed for different fuels and exhibited leaching of several abundant elements—Fe, Al, K, Na and Mn. Trace elements (Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Th, U, V, Zn) sometimes required up to 32 h for maximal extraction from ashes. Suggestions are presented regarding the chemical nature of trace elements in the untreated coals and ashes and suitable residence times for economical industrial processes. We think it possible to combine bacteriological oxidation of sulfidic concentrates of acid leaching from ash of various qualities or even whole coals.  相似文献   

Mais comment s'écoule donc un glacier ? Aperçu historique     

Frédérique Rémy  Laurent Testut 《Comptes Rendus Geoscience》2006,338(5):368-385

Ice and snow have often helped physicists understand the world. On the contrary it has taken them a very long time to understand the flow of the glaciers. Naturalists only began to take an interest in glaciers at the beginning of the 19th century during the last phase of glacier advances. When the glacier flow from the upslope direction became obvious, it was then necessary to understand how it flowed. It was only in 1840, the year of the Antarctica ice sheet discovery by Dumont d'Urville, that two books laid the basis for the future field of glaciology: one by Agassiz on the ice age and glaciers, the other one by canon Rendu on glacier theory. During the 19th century, ice flow theories, adopted by most of the leading scientists, were based on melting/refreezing processes. Even though the word ‘fluid’ was first used in 1773 to describe ice, more the 130 years would have to go by before the laws of fluid mechanics were applied to ice. Even now, the parameter of Glen's law, which is used by glaciologists to model ice deformation, can take a very wide range of values, so that no unique ice flow law has yet been defined. To cite this article: F. Rémy, L. Testut, C. R. Geoscience 338 (2006).  相似文献   

光催化降解乐果的动力学研究     

梁喜珍  黄国林  周跃明  李香枝 《华东地质学院学报》2006,29(1):80-83

采用30 W石英紫外灯作为光源,研究了乐果在二氧化钛悬浮体系中光催化降解反应的动力学规律。考察了乐果起始浓度、TiO2用量、溶液pH值及温度对乐果光催化降解速率的影响,结果表明,乐果光催化降解符合表观零级动力学规律。由于速率常数k与乐果起始浓度有关,表明乐果光催化降解反应不是一个简单的零级反应。  相似文献   

25～75℃酸性NaCl溶液中方铅矿的溶解动力学   总被引：4，自引：0，他引：4  

张生  李建平  王玉荣  胡光黔 《地球化学》2002,31(6):587-592

在25～75℃、pH=0.43～2.45的1mol/LNaCl溶液中进行了方铅矿的溶解动力学实验。发现在远平衡条件下,方铅矿的溶解速率r与氢离子活度犤H+犦呈线性关系,溶解速率方程(速率定律)为:r=k犤H+犦,即对H+而言,溶解反应为一级。其中速率常数k为2.344×10-7mol/m2·s(25℃)、1.380×10-6mol/m2·s(50℃)、7.079×10-6mol/m2·s(75℃)。溶解反应的活化能为43.54kJ/mol,方铅矿的溶解机理为表面化学反应,速率决定步骤为表面配合物的离解。  相似文献   

铅在高岭石表面的解吸动力学   总被引：3，自引：0，他引：3  

魏俊峰  吴大清  彭金莲  刁桂仪 《矿物岩石》2002,22(2):5-8

经过酸性条件下（pH=3.1)Pb(Ⅱ）高岭石表面解吸动力学的研究，发现解吸反应与吸附反应动力学相似，也是一个二阶段的过程，即初始的快速解吸之后伴随着一个缓慢的释放过程。在快速解吸阶段，7min内解吸量即已达到41％。吸附铅没有完全解吸，有近38％残留在高岭石表面，即解吸和吸附过程不是完全可逆的。解吸过程可以用扩展Elovich方程、Elovich方程、双常数方程和一级扩散方程较好地似合。  相似文献