硫酸根离子对方解石和白云石溶解度的影响   总被引：9，自引：3，他引：6  

闫志为 《中国岩溶》2008,27(1):24-31

在无CO2和有P_CO2条件下,利用目前成熟的水文地球化学模拟软件——PHREEQC,分别对方解石、白云石在Na2SO4、CaSO4和MgSO4溶液中的溶解度进行了模拟计算。结果显示:溶液中SO₄2-的存在对方解石、白云石溶解度的提高作用很大。如在Pco2、浓度为1200mmol／L的Na2SO4溶液中,方解石和白云石溶解度分别为纯水中溶解度的9．544和9．897倍。其作用机理是:在无同离子效应时,SO₄2-等所产生的盐效应和SO₄2-与各种阳离子形成的离子对起重要作用;而有同离子效应时,将发生白云石化或去白云石化反应,从而促使不全等溶解继续发生。与此同时,即使存在同离子效应的条件下,特别是在较高浓度条件下,盐效应的作用也是不容忽视的。   相似文献   

火山活动与辽西四合屯脊椎动物群死亡关系的初步研究   总被引：11，自引：0，他引：11  

郭正府  汪筱林 《岩石学报》2002,18(1):117-125

近年来在辽西北票四合屯发现了大量的早期岛类及“长毛”的小型兽脚类恐龙化石层,完美的化石形态表明本区发生过多次非正常生物集群死亡事件。化石层与火山凝灰岩层（或火山灰）密切共生在一起。本文选择了其中四个化石数量巨大的脊椎动物化石层,对其中凝灰岩（或火山灰）中的火山玻璃及五晶矿物内原生岩包裹体的挥发分成分进行了电子探针测定。研究结果表明,号世界相同成分的其它火山相比,本区火山喷出气体的含量较高;火山喷出的各种气体（HCl、HF、H2S、SO2、SO3和H2O蒸汽）的组成比例不同,对应着化层内脊椎动物化石组合也存在差异。作者认为,火山喷山的气体及火山灰（尘）的综合气体效应是造成本区生物集群死亡的重要原因。  相似文献   

Aqueous Oxidation of Sulfur(IV) Catalyzed by Manganese(II): A Generalized Simple Kinetic Model     

Boštjan Podkrajšek  Gorazd Berčič  Janja Turšič  Irena Grgić 《Journal of Atmospheric Chemistry》2004,47(3):287-303

The reaction kinetics of S(IV) autoxidation catalyzed by Mn(II) in the pH range 3–5 typical for atmospheric liquid water, was investigated. For reactions with pH maintained constant during the reaction course, the predictions obtained by a simple integral approach cover kinetic results only for concentrations of HSO ₃ ⁻ up to 0.2 mM at pH 4.5. Thus, a generalized simple kinetic model, which can be used for predicting the reaction kinetics in wider concentration, pH and temperature ranges, was derived. This model is based on the assumption that the reaction rate is proportional to the concentration of a transient manganese-sulfito complex formed in the initial step of a radical chain mechanism. In the proposed power law rate equation

SO}}_{\text{3}}^{{\text{(}}a - 1{\text{) + }}} ]^2 \cdot \frac{1} {{[{\text{H}}^ + ]^{0.5} }},$$" align="middle" vspace="20%" border="0">

the concentration of complex is calculated from the stability constant K and concentrations of reactants at a specific reaction time. This rate equation adequately predicts the reaction kinetics in the pH range 3–5, in the concentration ranges 0.1 ≤ [HSO ₃ ⁻ ] ≤ 0.4 mM and 2 ≤ [Mn(II)] ≤ 14.6 μM. For the temperature range 15–35 °C, the estimated value for activation energy is 92.0 ± 0.1 kJ mol⁻¹ and the Gibbs free energy of formation of the manganese-sulfito complex is −20.4 ± 0.3 kJ mol⁻¹. Furthermore, the kinetics for catalytic reactions with pH maintained constant during the reaction course as well as with initial pH adjusted only at the start of the reaction, is described satisfactorily by the present model.  相似文献   

The long-term simulation of surface SO2 and evaluation of contributions from the different emission sources to Beijing city     

YAN Peng  HUANG Jian  Roland Draxler 《中国科学D辑(英文版)》2005,48(Z2)

With a high-resolution SO2 emission inventory categorized by industries and seasons for Beijing city and gridded meteorological data fields from NCEP, the pollution dispersion model, HYSPLIT4 (Hybrid Single Particulate Lagrangian Integrated Trajectory, version 4), is used to determine the day-to-day variation of surface SO2 in Beijing for 2000 and 2001. Furthermore,the contributions of different emission sources in and around Beijing to the surface SO2 are studied. As shown in comparison with observations, the model does well in simulating the daily variation and seasonal distribution. The model computation of the annual source contributions to Beijing surface SO2 indicates that local emissions from the city give the largest contribution and the sources from the surrounding regions contribute only about 20%. During SO2 polluted or unpolluted days, the contribution from the latter can exceed 30%, and depending upon weather conditions, the contribution may exceed 40%. If the emissions from the surrounding sources during the winter heating season are assumed to be doubled in intensity, their contribution to surface SO2 in Beijing increased from 21% to 35% and 25% to 40% in 2000 and 2001, respectively. Evaluation of 7 types of emission sources identified for Beijing for their relative contribution to the concentration of surface SO2 has shown that area emissions by industrial production and furnaces, though discharging relatively small amounts (less than 1/3 of the total), have the largest contribution to the urban surface SO2, which is the key to the mitigation of the pollutant in the city.  相似文献   

Degree of Sulfate‐Reducing Activities on COD Removal in Various Reactor Configurations in Anaerobic Glucose and Acetate‐fed Reactors     

Dilek Erdirencelebi  Izzet Ozturk  Emine Ubay Cokgor  Gulseren Ubay Tonuk 《洁净——土壤、空气、水》2007,35(2):178-182

Sulfate‐reduction data from various anaerobic reactor configurations, e. g., upflow anaerobic sludge blanket reactor (UASBR), completely stirred tank reactor (CSTR), and batch reactor (BR) with synthetic wastewaters, having glucose and acetate as the substrates and different levels of sulfate, were evaluated to determine the level of sulfate‐reducing activity by sulfate‐reducing bacteria coupled to organic matter removal. Anaerobic reactors were observed for the degree of competition between sulfate‐reducing sulfidogens and methane producing bacteria during the degradation of glucose and acetate. Low sulfate‐reducing activity was obtained with a maximum of 20% of organic matter degradation with glucose‐fed upflow anaerobic sludge bed reactors (UASBRs), while a minimum of 2% was observed with acetate‐fed batch reactors. The highest sulfate removal performance (72–89%) was obtained from glucose fed‐UASB reactors, with the best results observed with increasing COD/SO₄ ratios. UASB reactors produced the highest level of sulfidogenic activity, with the highest sulfate removal and without a performance loss. Hence, this was shown to be the optimum reactor configuration. Dissolved sulfide produced as a result of sulfate reduction reached 325 mg/L and 390 mg/L in CST and UASB reactors, respectively, and these levels were tolerated. The sulfate removal rate was higher at lower COD/SO₄ ratios, but the degree of sulfate removal improved with increasing COD/SO₄ ratios.  相似文献   

Characteristics of Gaseous Pollutants at a Regional Background Station in Southern China          下载免费PDF全文

CHAO Na  JI Dong-Sheng  CHEN Jia-Shan  XIN Jin-Yuan  HU Bo  WANG Yue-Si  WANG Hui  MENG Ze 《大气和海洋科学快报》2014,(4):340-345

Measurements of gaseous pollutants （03, NOx, SO2, and CO） were conducted at Dinghushan background station in southern China from January to December 2013. The levels and variations of O3, NOx, SO2, and CO were analyzed and their possible causes discussed. The annual average concentrations of 03, NOx, SO2, and CO were 24.6 ± 23.9, 12.8 ± 10.2, 4.0 ± 4.8, and 348 ± 185 ppbv, respectively. The observed levels of the gaseous pollutants are comparable to those at other background sites in China. The most obvious diurnal variation of 03 was observed in autumn, with minima in the early morning and maxima in the afternoon. The diurnal variations of SO2 showed high values during the day. The diurnal cycles of NOx showed higher values in the morning and lower values during the night. Higher CO concentrations were observed in spring followed by winter, autumn, and summer. Biomass burning, in combination with the transport of regional pollution, is an important source of CO, SO2, and NOx in spring and winter. Backward trajectories were calculated and analyzed together with corresponding pollutant concentrations. The results indicate that air masses passing over polluted areas are responsible for the high concentrations of gaseous pollutants at the Dinghushan background station.  相似文献   

磷灰石结构中[SO_4]、[SiO_4]四面体的喇曼谱学特点     

刘羽 《矿物岩石地球化学通报》1999,(4)

磷灰石是重要的生物材料矿物。天然磷石晶体结构中［ＰＯ４］３－能广泛地被［ＳｉＯ４］、［ＳＯ４］类质同象取代,形成含硅硫磷灰石以至硅硫磷灰石［１］。据报道,在合成羟磷灰石中引入部分Ｓ、Ｓｉ离子将提高其抗蚀性能,因此［ＳｉＯ４］与［ＳＯ４］对［ＰＯ４］的四面体替换是磷灰石晶体化学研究的重要内容［２～４］。振动光谱（包括喇曼与红外光谱）是研究晶体结构络阴离子行为的主要手段之一。对磷灰石中磷氧四面体振动谱学特点的研究,无论是理论计算还是实验结果均已十分成熟［５,６］,但对其结构中硫氧、硅氧四面体的喇曼光…  相似文献   

上海市气象场与SO₂浓度数值模拟          下载免费PDF全文

余瑶  刘品高  陈万隆 《大气科学学报》2003,26(1):47-55

采用地形坐标系下适合于复杂地形且满足地-气耦合的静力学三维中-β尺度气象预报模式,使用08时的实测流场经变分法初始化后得到的初始流场,模拟研究了上海地区的局地流场时空演变特征。模式较细致地考虑了湍流、长短波辐射、凝结、蒸发、地表热力平衡等因子,在此基础上,使用有限元法数值求解一阶闭合的三维欧拉平流扩散方程,模拟了上海地区的SO₂浓度分布。结果表明:上海的局地流场具有明显的日变化特征,受海陆温差的影响明显,日间风速较夜间风速大,风向呈顺时针旋转;在不稳定层结情况下,高架点源排放的高空污染物对地面的污染物浓度有贡献,会造成地面污染物浓度升高。  相似文献