Methods of metal release assessment in soil water at anoxic sites     

Nele Schuwirth  Thilo Hofmann 《洁净——土壤、空气、水》2006,34(6):579-586

Metal mobility at contaminated sites can be assessed by soil water investigations or by leaching tests. Leaching tests are usually carried out in open contact with the atmosphere disregarding possible changes of redox conditions. This can affect the original metal speciation and distribution, particularly when anoxic samples are investigated. In this study, the applicability of common leaching tests (the German S4 test (S4), ammonium nitrate extraction (AmmN), and saturation soil extraction (SSE)) is tested for the assessment of zinc release from sulfide‐bearing flotation residues of a former ore mine. Results are compared to soil solution samples obtained by centrifugation and suction cups. The influence of sample storage on S4 leaching test results is investigated in a long‐term study to assess oxidation kinetics. Within the first 200 days the release of zinc increases with a slope of 0.1 mmol kg^–1 d^–1 or 6.0 mg kg^–1 d^–1, respectively. Since oxidation of the sulfide‐bearing samples leads to a significant overestimation of metal release, a feasible modification for the conduction of leaching tests for anoxic material is proposed where oxidation is prevented efficiently. The modified SSE is found to be the only of the tested leaching procedures, which can be recommended for the assessment of current soil water concentrations at anoxic sites if direct investigation of the soil water is impossible due to technical reasons.  相似文献   

密闭体系与开放体系模拟实验结果的比较研究及其意义   总被引：3，自引：0，他引：3  

卢双舫  王民  王跃文  徐立恒  薛海涛  李吉君 《沉积学报》2006,24(2):282-288

利用广泛应用的高压釜和Rock Eval热解实验技术，对松辽盆地3个有机质样品同时进行了密闭条件下的加水恒温热解实验和开放条件下的恒速升温热解实验。利用后一实验数据所标定得到的化学动力学模型计算了与高压釜相同实验条件下的有机质产油、产气率。结果表明，在线计量的恒速升温Rock Eval实验方法由于不损失C6—C13的轻质烃组分，在计量液态油的产量方面较需要抽提、恒重的高压釜实验方法更为准确。因此为解决热模拟实验中难以计量、但对成烃评价有重要意义的C6—C13组分的计量问题提供了一条有效的途经。这可能也表明，先由实验数据建立有关的化学动力学模型，之后由它来进一步计算有机质的成烃率，不仅是可行的，而且应该更为准确。  相似文献   

Relations between Light Hydrocarbon, Carbon Monoxide, and Carbon Dioxide Concentrations in the Plume from the Combustion of Plant Material in a Furnace     

S. Yonemura  S. Sudo  H. Tsuruta  S. Kawashima 《Journal of Atmospheric Chemistry》2002,43(1):1-19

To systematically explain relations between light hydrocarbons, CO, and CO₂ concentrations/emissions of biomassburning, we measured concentrations/emissions of carbon gases – CO,CO₂, light hydrocarbons (CH₄, C₂H₆,C₂H₄, C₂H₂, C₃H₈, C₃H₆,n-C₄H₁₀, i-C₄H₁₀, n-C₅H₁₂,i-C₅H₁₂), and THC (total hydrocarbon) – in the burning of dead plant material, mainly Imperata grass, byclosed-chamber experiments and by time-series analyses of gas concentrations in combustion plumes in relatively efficient and inefficient combustion situations. Concentrations of hydrocarbons measured were well correlated to [CO] although [C₂H₂] was exceptionally well correlated to[CO₂]. The phase diagrams (relation between [CO]/ [CO₂] and [hydrocarbon]/ [CO₂]) obtained by the time-seriesexperiments well illustrated the variation in the overall emission rates of the closed-chamber experiments. The higher rates of decrease in hydrocarbon concentration with increasing carbon number in the efficient case compared with the inefficient case probably reflected the rate of oxidation and the amount of radicals. The overall concentrations (or emissions) of C₂H₄ and C₃H₆ were higher thanthose of C₂H₆ and C₃H₈, suggesting a linkage to mechanisms in whichthe predominant path of hydrocarbon oxidation is through the degradation of alkyl radicals, which can be immediately converted into or formed from alkenes. For C₃ and C₄ species, normal-chain species hadhigher emissions than iso-chain species under lower combustion efficiency. This may be attributable to the presence of tertiary C–H bonds in iso-species,which show more reactivity in the abstraction of H than secondary C–H bonds unless the carbon number is large.  相似文献   

陆相低成熟烃源岩有机硫与热解成烃动力学关系初探   总被引：5，自引：0，他引：5  

沈忠民  周光甲 《沉积学报》1998,16(4):133-139

对陆相低成熟烃源岩（R_o≤ 0.5 %）有机硫与成烃动力学关系进行了研究。结果表明:①有机硫含量与镜质体反射率（R_o）之间呈负相关关系,即有机硫含量随成熟度提高而减少;②源岩的平均活化能（E）有随有机硫含量增大而减小的趋势;③有机硫含量与源岩活化能分布最小值（E_min）和经可溶有机质抽提后的活化能分布最小值（E_min）之间存在正相关关系;④活化能分布范围E_min～ESE_min（ESE_min＞E_min）内的可溶有机质生烃能力与有机硫含量具有一定的相关性;⑤综上结果推断东营凹陷南斜坡东段沙四段（Es₄）源岩中的有机硫在成烃过程中可能起到了一定的作用。  相似文献   

High Resolution Stepped-Combustion Mass Spectrometry: Application to the Detection and Analysis of Fine-Grained Diamond in Meteorites and Rocks     

Stuart R. Boyd  Ian P. Wright  Conel M.O'D. Alexander  C.T. Pillinger 《Geostandards and Geoanalytical Research》1998,22(1):71-83

An analytical system and operating protocol are described for high resolution, stepped-combustion mass spectrometry, designed for the extraction, purification, quantification and isotopic analysis of light elements (e.g. C and N) in fine-grained reduced components (e.g. diamond) which have been chemically extracted from natural samples (e.g. meteorites). Specifically, a simple model has been developed for the extraction of diamond from meteorite and its analysis by high resolution stepped heating under an atmosphere of oxygen. Changes in the pressure of oxygen within the range 1.3 to 12kPa (10 to 90 torr) were not found to have any detectable effect on the combustion. Results obtained by this procedure were compared with those predicted by a model and excellent agreement was found, taking into account the limitations of this approach. Results of a preliminary attempt to find fine-grained diamond in a lamproite are outlined.  相似文献   

煤矸石-水相互作用的溶解动力学及其环境地球化学效应研究   总被引：17，自引：1，他引：17  

党志 《矿物岩石地球化学通报》1997,(4)

煤矸石—水相互作用的溶解动力学及其环境地球化学效应研究党志（中国科学院地球化学研究所，贵阳５５０００２）关键词水—岩作用煤矸石地球化学动力学采煤矿区复垦环境效应收稿日期：１９９７－３－１０作者简介：党志男１９６２年生博士生环境地球化学煤矸石以其量多、...  相似文献   

催化动力学光度法测定痕量钛的研究   总被引：2，自引：0，他引：2  

汪燕芳  周松茂 《岩矿测试》1997,16(4):307-309

在氨性介质中，痕量Ｔｉ（Ⅳ）催化ＫＩＯ４氧化靛红的褪色反应。褪色程度与Ｔｉ（Ⅳ）的浓度在０～８μｇ／Ｌ线性相关；对于靛红褪色反应为零级，对于Ｔｉ（Ⅳ）该反应为一级；测定该反应的表观活化能为７０４５ｋＪ／ｍｏｌ；反应速率关系式是－ｄＣＲ／ｄｔ＝ＫＣＴｉ。基于该反应，建立测定痕量Ｔｉ的方法，其检出限５０５×１０－９ｇ／Ｌ；ＲＳＤ（ｎ＝６）＜５２％，干扰可经伯胺Ｎ１９２３萃取分离消除。方法用于人发样中痕量Ｔｉ（Ⅳ）的测定，结果与极谱法相符。  相似文献   

Effect of Sediment Motion Patterns on Sorption of Cadmium Ions by Sediment Particles     

HUANG Suiliang  Associate Professor  Dr.  Water Environment Simulation Laboratory  State Key Joint Laboratory of Environmental Simulation  Pollution Control  Beijing Normal University  Beijing  WAN Zhaohui Professor  Dr.  Department of Sedime 《国际泥沙研究》1997,(3)

I.INTRODUCTIONThefateofmanytraceheavymetalsinnaturalwatersis,toalargeextent,controlledbysorptionprocessesandthedynamicsoftheparticlesthemselves.Thepotentialinfluencesofenvironmentalvariablessuchastemperature,CaZ+,Na+andCI--,dissolvedorganiccarbonandPHvaluesontraceheavymetalpartitioninghavebeenwidelyinvestigated.Forexample,StumnandMorgan(1981)suggestthattheextentofsorptionvariespositivelywithtemperature.Itfollowsthatdecreasedsorptionmightbeexpectedatlowtemperatures,e.g.duringwintermont…  相似文献   

镜质体成烃反应动力学模型的标定及其在热史恢复中的应用   总被引：5，自引：1，他引：5  

卢双舫  王子文  付晓泰  王振平 《沉积学报》1996,(4)

镜质体反射率（Ｒｏ）与其生烃率有关，因此，由Ｒｏ应可求取其生烃率；同时，在求取了镜质体成烃反应动力学参数之后，若已知其受热史，则可计算出镜质体的生烃率；反过来，若已知镜质体的生烃率，应可反推其受热史。基于这一基本原理，本文在建立和标定镜质体成烃反应动力学模型的基础上推导了可将其应用于存在着抬升、剥蚀和古地温非线性变化等复杂地质条件下热史恢复的原理模型，结合海拉尔盆地海参７井的实测Ｒｏ值，有效地恢复了其古热史  相似文献   

不同粒径泥沙共存吸附动力学模式研究   总被引：2，自引：0，他引：2       下载免费PDF全文

黄岁梁 《水科学进展》1996,7(2):138-143

天然水体中泥沙组成具有非恒定性和非均匀性,而不同粒径泥沙的吸附能力差异很大.因此.讨论天然水体中泥沙对重金属污染物的自净能力,必须研究不同粒径泥沙共存(即非均匀沙)的吸附模式.通过系统室内静态试验,研究了不同粒径泥沙共存吸附的吸附动力学模式.它表明,不同粒径泥沙共存吸附体系各粒径之间不存在竞争和干扰,共存体系单位重量泥沙的吸附量等于各粒径泥沙单独存在,在相同条件下单位重量泥沙的吸附量乘以其在共存体系中所占份额的和.这在一定程度上解决了天然河流水体泥沙吸附量的计算问题.  相似文献