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1.
采用单因素及静态实验方法,研究从污水厂活性污泥中富集分离的硫酸盐还原菌(sulfate-reducing bacteria,SRB)在不同初始pH值条件下对SRB脱硫率的影响。试验结果显示,该SRB菌种生长在偏弱酸-中性环境中。当pH=6~7时,最适宜SRB生长,脱硫率达到最高;当pH=3~4时SRB难以生长,脱硫率接近于零。菌液中的金属铀的存在会抑制SRB菌的生长,铀浓度越高,抑制作用越严重。  相似文献   

2.
硫酸盐还原菌(SRB)分解硫酸盐矿物对C、S、Fe、Sr、Ba等元素的循环起着重要制约作用,二者相互作用机制的阐明具有重要的矿物学、地球化学及地质微生物学意义。通过设计厌氧实验,本文探讨了SRB与硬石膏的作用过程及机理。结果表明,较之无菌体系,SRB体系中氧化还原电位(EORP)显著降低;可挥发性硫(AVS)与蛋白质浓度则不断增大;硬石膏中总溶出硫含量增加;硬石膏表面SRB粘附位置出现明显溶蚀现象。分析表明SRB通过两种机制促进硬石膏分解:SRB还原代谢消耗溶解态SO42-,降低SO42-浓度,进而促使硬石膏持续溶解;SRB粘附于硬石膏表面,其自身及代谢产物通过络合硬石膏中的Ca加速矿物分解,此种机制在前人的研究中被普遍忽略,而通过此机制SRB亦可促进难溶硫酸盐(天青石、重晶石等)及铁氧化物的溶解,进而制约相关元素的地球化学行为。  相似文献   

3.
生物去除地下水中硫酸盐的实验研究   总被引:1,自引:0,他引:1  
张宏涛  翟辉 《地下水》2005,27(1):19-22
使用平皿夹层厌氧法分离得到纯化的硫酸盐还原菌,通过对比封口、敞口两种情况下细菌培养过程中产生的现象和细菌的生长曲线,表明SRB并非严格的厌氧菌,能耐受一定浓度的环境溶解氧.将该菌用于去除溶液中的SO42-,发现SRB在还原SO42-的过程中,随着SO42-去除率的增加,溶液的pH值会减小,而当SO42-去除率降低时,溶液的pH有增加的趋势;COD/SO42-比值对SO42-的去除率有很重要的影响,在封口情况下,COD/SO42-=0.75时SO42-的最大去除率约为48.60%,COD/SO42比值增加至2.5时,SO42-最大去除率可以达到89.72%,要达到SO42-高去除率,必须增加COD/SO42-比值.  相似文献   

4.
铁氧化物对硫酸盐还原菌分解硫酸盐矿物的协同作用   总被引:5,自引:0,他引:5  
以牛肉膏为碳源,用活性污泥混合菌接种,探讨在缺氧条件下添加不同的铁氧化物对硫酸盐还原菌(SRB)分解硫酸盐矿物的影响。通过溶液pH、铁离子、硫酸根浓度以及固体产物的SEM和EDS图谱分析,揭示硫酸盐矿物分解过程和机制。实验结果表明,铁氧化物对SRB分解硫酸盐矿物起着明显的协同作用:①被铁还原菌还原的Fe2+与硫酸盐还原产生的硫化氢反应形成铁硫化物,消除硫化氢对SRB分解硫酸盐的抑制作用;②铁氧化物还原溶解,提高体系的pH和碱度,增加生化产物CO2的溶解,诱导溶解的钙离子形成方解石沉淀,促进SRB分解硫酸盐矿物的过程。  相似文献   

5.
利用厌氧微生物分离技术,对深度为1.2 m 的海南红树林湿地沉积物钻孔样品进行了分离培养,共获得11 株 厌氧sulfate-reducing bacteria(SRB) 菌株。经显微观察和16S rDNA序列分析,可归纳为6个属,其中已经报道有芽孢杆菌 属(Bacillus)、弧菌属(Vibrio) 和梭状芽胞杆菌属(Clostridium),另外3个属分别为伯克霍尔德菌属(Burkholderia)、希瓦氏菌属(Shewanella) 和海杆菌属(Marinobacterium)。不同属的细菌对硫酸盐还原的速率最低为14.71%,最高可达 56.78%,并且以上6属11株菌都能将+6价的硫还原生成-2价硫,并与培养基中的Fe2+结合生成黑色FeS沉淀,而这些无定 形FeS沉淀是生成黄铁矿的前体。红树林湿地SRB种群数量随沉积物深度的增加而降低,结合沉积物的地球化学分析测试 结果表明,表层(0 cm) 水界面的沉积物由于处于氧化-还原界面,氧气的周期性输入在一定程度上抑制了SRB的生长;随着 深度增加(10~40 cm),充足的有机质、偏中性的pH值以及厌氧环境的增强,使得SRB种类和数量明显增加;而60 cm以下 沉积物中因TOC含量降低,减少了微生物可利用的碳源,pH值明显降低,Na+和Ca2+离子浓度明显增加,这些因素都抑制了 SRB的生长,使得深部沉积物中SRB的种类和数量显著减少。  相似文献   

6.
石膏在有机物厌氧分解中的固碳效应   总被引:2,自引:0,他引:2  
本文以牛肉膏蛋白胨为厌氧微生物的营养源,研究了石膏对厌氧微生物生化系统中甲烷释放量和有机物矿化的影响.根据溶液中总有机碳(TOC)、总无机碳(TIC)、硫酸根、硫化物、pH值以及气体中CO2,CH4和H2S的释放量的观测,以及固体产物的扫描电镜(SEM)、能谱(EDS)、X-射线衍射(XRD)分析结果,探讨了石膏对抑制...  相似文献   

7.
本文研究了微生物的铁还原作用对黏土矿物有机质保存的影响。将一种有机化合物(十二氨基十二酸)插层到一种富铁的蒙脱石(绿脱石)中,利用硫酸盐还原菌(Desulfovibrio vulgaris)分别对插层前后的绿脱石进行作用,以研究该菌对绿脱石结构中Fe3+的还原作用以及层间有机物的影响。结果发现,1Desulfovibrio vulgaris能够还原这2种绿脱石结构中的Fe3+,且电子穿梭体AQDS(蒽醌-2,6-二磺酸)能够增强还原速率和程度;2硫酸盐的存在能够增加还原速率和程度,表明还原过程中生成的硫化物与绿脱石结构中的Fe3+发生了化学还原作用;3通过X射线衍射、红外光谱、总有机碳分析表明,还原后的绿脱石,其结构层内仍有大量有机物,具有一定的稳定性和保存层间有机质的能力。  相似文献   

8.
硫酸盐还原菌是厌氧环境中参与砷形态转化的重要微生物种群,其介导的生物地球化学循环过程对铁氧化物表面吸附态砷迁移转化的影响亟待深入研究.选取江汉平原典型高砷含水层原位沉积物分离纯化出一株严格厌氧硫酸盐还原菌Desulfovibrio JH-S1,对其进行砷和铁还原能力鉴定,并通过模拟培养实验探究硫酸盐还原菌参与下的铁矿物相转化对吸附态砷迁移的影响.Desulfovibrio JH-S1具有Fe(III)还原能力,无硫和有硫体系中Fe(III)均能被还原,但在硫酸盐充足条件下铁还原量显著增加;该菌株不具备As(V)还原能力,但添加硫酸盐的培养体系中As(V)去除率可达96%以上.Desulfovibrio JH-S1能够还原硫酸盐从而促进载砷的水铁矿还原转化为纤铁矿,并导致吸附的砷释放.江汉平原高砷含水层土著硫酸盐还原菌兼具硫酸盐/铁还原功能,参与了高砷含水层系统中砷-铁-硫耦合循环,对高砷地下水的形成具有重要作用.   相似文献   

9.
刘畅  陈天虎  周跃飞  金杰 《矿物学报》2011,31(4):742-749
探讨了固定床除Cr工艺以油菜秆为微生物生长的缓释碳源,含SRB的混合微生物和油菜秆对Cr(Ⅵ)的还原和固定的共同作用。动态实验分2阶段开展:初始2周的驯化阶段和梯度增加Cr(Ⅵ)浓度的除Cr实验阶段。除Cr实验中,间歇对固定床出水pH、氧化还原电位、SO42-及硫化物浓度、DOC、Cr(Ⅵ)浓度进行测试,实验结束后对固定床中固体产物进行SEM、EDS和XPS等分析。结果表明,油菜秆固定床处理模拟含Cr(Ⅵ)废水效果明显。当进水Cr(Ⅵ)浓度ρ[Cr(Ⅵ)]〈19.52 mg/L时,出水Cr(Ⅵ)和Cr(Ⅲ)浓度均低于排放标准(0.05 mg/L);Cr(Ⅵ)被还原为Cr(Ⅲ),Cr(Ⅲ)以氢氧化物的形式沉淀附着于油菜秆和其它固体物质之上。分析认为,油菜秆在固定床处理模拟含Cr(Ⅵ)废水中所起的作用主要包括3方面(作为微生物生长的缓释碳源;吸附Cr(Ⅵ),降低其对微生物的毒性;作为Cr(Ⅲ)矿化产物的沉淀附着界面);Cr(Ⅵ)主要通过SRB的直接作用及H2S的作用被还原为Cr(Ⅲ);以油菜秆为碳源的固定床处理Cr(Ⅵ)的浓度上限介于15.05~19.52mg/L之间。  相似文献   

10.
王红梅  刘烁  刘邓 《地球科学》2015,40(2):305-316
选取酸性矿坑水环境中常见的次生含铁硫酸盐矿物———黄钾铁矾[KFe3(SO4)2(OH)6]为研究对象,用硫酸盐还原菌 Desulfovibriovulgaris 和异化铁还原菌Shewanellaputrefaciens CN32对其进行还原实验,探讨作为重金属治理潜在材料的 黄钾铁矾的微生物稳定性.实验采用非增长型培养基,在中性、厌氧、30℃的条件下进行.采用湿化学方法测量水溶液及还原产 生的总Fe2+ ,利用X射线衍射(X-raydiffraction,简称XRD)来分析反应后残余固体物质的矿物组成,用扫描电镜(scanning electronicmicroscopy,简称SEM)观察固体残余物的形貌特征.结果表明,没有微生物的参与,黄钾铁矾的稳定性较好.异化铁 还原菌S.putrefaciens CN32和硫酸还原菌D .vulgaris 在营养极其匮乏的中性厌氧条件下均能还原黄钾铁矾晶格中的 Fe3+ ,显示出黄钾铁矾被微生物还原的可能性.S.putrefaciens CN32还原黄钾铁矾晶格中Fe3+ 的最大还原速率和最终Fe3+ 还原率分别为0.001mmol·L-1·h-1和0.37%.与S.putrefaciens CN32不同,D .vulgaris 对黄钾铁矾的还原能力较强,不 含有电子穿梭体(Anthraquinone-2,6-disulfonate,简称AQDS)的实验体系中Fe3+ 的最大还原速率和最终Fe3+ 还原率分别为 0.017mmol·L-1·h-1和16.80%,而添加了AQDS的实验体系的则分别达到了0.026mmol·L-1·h-1和24.30%,这可能与 黄钾铁矾中含有SO42- 有关.D .vulgaris 优先还原黄钾铁矾晶格中的SO42- 产生的H2S是强还原剂,也可促进Fe3+ 的还原, 微生物以及H2S的双重作用可能是导致D .vulgaris 体系中Fe3+ 还原率较高的原因.XRD分析表明,黄钾铁矾经过S.putrefaciens CN32的作用,物相没有发生变化;而经过D .vulgaris 作用后,黄钾铁矾的特征峰消失,固相残余物中出现了菱铁 矿(FeCO3)、蓝铁矿[Fe3(PO4)2·8H2O]等次生矿物.由于培养基中没有添加任何的磷酸盐,因此蓝铁矿的出现可能是由于培 养基中添加的少量酵母浸膏降解后产生的磷酸根与D .vulgaris 还原黄钾铁矾产生的Fe2+ 相互作用的结果.这些认识对深入 理解地球表层铁的生物地球化学循环具有重要意义,为矿山环境重金属的污染治理提供了实验依据.   相似文献   

11.
以天然纳米矿物纤蛇纹石和酸浸二氧化硅为载体,钛酸四丁酯为钛源,在室温条件下采用溶胶-凝胶法,制备了负载TiO_2的复合光催化材料。采用气体吸附、扫描电子显微镜(SEM)、X射线衍射(XRD)等方法对载体和不同温度煅烧得到的样品进行微观形貌和结构分析,并在紫外光照射下,以10 mg/L罗丹明B为目标污染物评价不同样品的光催化活性。结果表明,750℃煅烧的酸浸二氧化硅负载TiO_2复合材料的光催化性能最好,光照40 min对罗丹明B的去除率达到91.57%,载体良好的吸附能力能够促进污染物的降解。  相似文献   

12.
The viscosity of a synthetic andesite-like melt was measured in the low viscosity range (101-106 Pa s) using the falling sphere(s) method and in the high viscosity range (108-1013 Pa s) using parallel-plate viscometry. Falling sphere experiments with melts containing 2.3 and 5.6 wt.% H2O were carried out in an internally heated gas pressure vessel (IHPV) at 500 MPa confining pressure. The sinking velocity of Pt and Pd spheres and in one case of a corundum sphere was used to measure the melt viscosity. In addition, a creep experiment was performed at ambient pressure using a glass containing 2.73 wt.% H2O . A more water-rich glass (5.6 wt.% H2O ) was investigated with a high pressure parallel-plate viscometer at 400 MPa confining pressure in an IPHV. By combining our new data with previous results for a similar melt composition we derived the following expression to describe the viscosity η (in Pa s) as a function of temperature T (in K) and water content w (in wt.%)
  相似文献   

13.
塔河地区中下奥陶统储层硫化物成因分析   总被引:1,自引:0,他引:1  
研究表明塔河地区中下奥陶统碳酸盐岩储层后期受到了大气淡水和深部热卤水的成岩改造作用。这些储层天然气中含有高达8.3%H2S气体,裂缝与孔洞充填方解石流体包裹体中气相组分含有高达11%的H2S。这些方解石的均一化温度以110.2~198.9℃为主,而且,H2S气体、原油和黄铁矿集合体δ34S值主要介于18‰~22‰,这些特征显示,硫化物形成于相对高温条件下热化学硫酸盐还原-有机质氧化作用(TSR)。有机质被氧化的证据包括高温方解石具有轻δ13C特征(δ13C为-4.3‰~-8.3‰)以及现今地层水具有轻δ13CHCO3-值(-6.0‰~-13.8‰)。现今油气藏中TSR成因H2S浓度低于流体包裹体,应该与H2S沉淀为黄铁矿、合并入原油中而导致富硫原油产生有关。一些黄铁矿具有很轻的δ34S值,可轻达-26‰,为微生物硫酸盐还原成因,但是其分布比较局限。  相似文献   

14.
The synthetic amphibole Na0.95(Li0.95Mg1.05)Mg5Si8O22(OH)2 was studied in situ at high-T, using IR OH-stretching spectroscopy and synchrotron X-ray powder diffraction. At room-T the sample has P21 /m symmetry, as shown by the FTIR spectrum. It shows in the OH region two well-defined and intense absorptions at 3,748 and 3,712 cm−1, respectively, and two minor bands at 3,667 and 3,687 cm−1. The main bands are assigned to the two independent O–H groups in the primitive structure. The two minor bands evidencing the presence of small amount of vacant A-site (A0.05). With increasing T, these bands shift continuously and merge into a unique absorption at high temperature. A change as a function of increasing T is revealed by the evolution of the refined unit-cell parameters, whose trend shows a transition to C2/m at about 320–330°C. The spontaneous scalar strain, fitted with a tricritical 2–6 Landau potential, gives a T c of 325(10)°C (β parameter = 0.27). Comparison with the second-order P21 /mC2/m phase transition at 255°C for synthetic amphibole ANa0.8B(Na0.8Mg1.2)CMg5Si8O22(OH)2 indicates that the substitution of Na with Li at the B-sites strongly affects the thermodynamic character and the T c of the phase transition. The comparison of LNMSH amphiboles with cummingtonitic ones shows that the high-T thermodynamic behaviour is affected by A-site occupancy.  相似文献   

15.
Hydrometallurgical processing of spent hydrodesulphurisation (HDS) catalyst for the recovery of molybdenum using sodium carbonate and hydrogen peroxide mixtures was investigated. The results indicated that the recovery of molybdenum was largely dependent on the concentrations of Na2CO3 and H2O2 in the reaction medium, which controls the acidity of the leach liquor and carry over of impurities such as Al, Ni, P, Si and V. Leaching process was exothermic and leaching efficiency of molybdenum decreased with increasing solid to liquid ratio. Large scale leaching of spent catalyst, under optimum conditions: 20% pulp density, 85 g/L Na2CO3, 10 vol.% H2O2 and 1 h reaction, resulted a leaching efficiency of 84% Mo. The obtained leach liquor contained (g/L): Mo — 22.0, Ni — 0.015 and Al — 0.82, P — 1.1, Si — 0.094 and minor quantities of V — 8 mg/L, As and Co — < 1 mg/L. Recovery of Mo from leach solution as MoO3 of 97.30% purity was achieved by ammonium molybdate precipitation method.  相似文献   

16.
Classical atomistic simulation techniques have been used to investigate the energies of hydrogen defects in Mg2SiO4 and Mg2GeO4 spinels. Ringwoodite (γ-Mg2SiO4) is considered to be the most abundant mineral in the lower part of the transition zone and can incorporate large amounts of water in the form of hydroxyls, whereas the germanate spinel (γ-Mg2GeO4) corresponds to a low-pressure structural analogue for ringwoodite. The calculated defect energies indicate that the most favourable mechanisms for hydrogen incorporation are coupled either with the reduction of ferric iron or with the creation of tetrahedral vacancies. Hydrogen will go preferentially into tetrahedral vacancies, eventually leading to the formation of the hydrogarnet defect, before associating with other negatively charged point defects. The presence of isolated hydroxyls is not expected. The same trend is observed for germanate, and thus γ-Mg2GeO4 could be used as a low-pressure analogue for ringwoodite in studies of water-related defects and their effect on physical properties.  相似文献   

17.
朱光有  费安国  赵杰  刘策 《岩石学报》2014,30(12):3772-3786
热化学硫酸盐还原反应(TSR)是深层碳酸盐岩油气藏中硫化氢的主要成因机制,目前已在全球发现了50多个TSR成因的大中型含硫化氢天然气田。通过对中国四川盆地含硫化氢气田硫化物的采集与同位素分析,结合全球含硫化氢天然气田硫同位素分析数据,研究了TSR过程中硫同位素的地球化学行为和分馏特征。研究发现,TSR成因的高含硫化氢天然气中,硫化氢与硫酸盐的硫同位素分馏值小于15‰,主要分布范围为2.5‰~13.82‰,平均在10‰。四川盆地海相层系膏岩的硫同位素值分布较宽,并呈现阶梯状变化,而硫化氢的硫同位素则呈现出相似的分布规律,表明各主要含硫化氢气田硫化氢中的硫来自于本层系的硫酸盐,TSR主要发生在各自的储集层中。四川盆地各气田TSR发生的温度条件相似,硫同位素分馏比较接近。TSR过程中硫同位素的分馏过程与硫酸盐本身硫同位素值的高低无关,而与TSR反应程度有关。TSR反应程度越高,硫化氢的硫同位素值与地层硫酸盐的硫同位素越相近。通过系统分析整理全球含硫化氢气田的硫化物硫同位素数据,并结合四川盆地地质条件和油气演化过程,揭示了TSR过程中硫同位素的分馏特征,并绘制出四川盆地和全球各时代硫化氢和石膏的硫同位素分布曲线图,为研究含油气盆地蒸发岩沉积演化和硫化氢成因提供了参考。  相似文献   

18.
Torsion experiments were performed on the Al2SiO5 polymorphs in the sillimanite stability field to determine basic rheological characteristics and the effect of deformation on polymorphic transformation. The experiments resulted in extensive transformation of andalusite and kyanite to sillimanite. No transformation occurred during the hot-press (no deformation) stage of sample preparation, which was carried out at similar PT conditions and duration as the torsion experiments. Experiments were conducted on fine-grained (< 15 µm) aggregates of natural andalusite, kyanite and sillimanite at 1250 °C, 300 MPa, and a constant shear strain rate of 2 × 10− 4/s to a maximum shear strain of 400%. Electron back-scattered diffraction (EBSD) analysis of the experiments revealed development of lattice-preferred orientations, with alignment of sillimanite and andalusite [001] slightly oblique to the shear plane. The kyanite experiment could not be analyzed using EBSD because of near complete transformation to sillimanite. Very little strain ( 30%) is required to produce widespread transformation in kyanite and andalusite. Polymorphic transformation in andalusite and kyanite experiments occurred primarily along 500 µm wide shear bands oriented slightly oblique and antithetic to the shear plane and dominated by sub-µm (100–150 nm) fibrolitic sillimanite. Shear bands are observed across the entire strain field preserved in the torsion samples. Scanning transmission electron microscope imaging shows evidence for transformation away from shear bands; e.g. fibrolitic rims on relict andalusite or kyanite. Relict grains typically have an asymmetry that is consistent with shear direction. These experimental results show that sillimanite is by far the weakest of the polymorphs, but no distinction can yet be made on the relative strengths of kyanite and andalusite. These observations also suggest that attaining high bulk strain energy in strong materials such as the Al2SiO5 polymorphs is not necessary for triggering transformation. Strain energy is concentrated along grain boundaries, and transformation occurs by a dynamic recrystallization type process. These experiments also illustrate the importance of grain-size sensitive creep at high strains in a system with simultaneous reaction and deformation.  相似文献   

19.
Numerical models on thermal structure, convective flow of solid, generation and transportation of H2O-rich fluid in subduction zones are consolidated to have a comprehensive view of the subduction zone processes: heat balance, circulation of H2O magmatism–metamorphism, growth of arcs and continental margins. A large scale convection model with steady subduction of a cold old slab (130 Myr old) predicts rapid ( 100 Myr) cooling of subduction zones, resulting in cessation of magmatism. The model also predicts that the mantle temperature beneath arcs and continental margins is greatly affected by the effective temperature of the subducting slab, i.e., the age of the subducting slab. If subduction of a young hot slab, including ridge subduction, occurs every 60 to 120 Myr as is suggested for eastern Asia, the average temperature beneath arcs is increased by about 300 °C, which may explain the long-lasting magmatism in eastern Asia. Associated with subduction of young slabs and ridges, thermal structure and circulation of H2O are greatly modified to cause a transition from (1) normal arc magmatism, (2) forearc mantle melting, to (3) slab melting to produce a significant amount (100 km3) of granitic melts, associated with both high-P/T and low-P/T type metamorphism. The last stage of (3) can result in formation of a granitic batholith belt and a paired metamorphic belts. Synthesis of the numerical models and observations suggest that episodic subduction of young slabs and ridges can explain heat source for generating a large amount of granitic magmas of batholiths, synchronous formation of batholith and regional metamorphic belts, and PT conditions of the paired metamorphism. Even the high-P/T metamorphism requires an elevated geothermal structure in the forearc region, associated with ridge subduction. Although the emplacement of the batholiths and the regional metamorphic belts, and the mass balance in subduction zones are not well constrained at present, the episodic event associated with ridge subduction is thought to be essential for net growth of arcs and continental margins, as well as for the long-term heat balance in subduction zones.  相似文献   

20.
鄂尔多斯盆地东南部广泛发育黄铁矿,通过对黄铁矿的矿物学特征、元素组成、硫同位素等的分析,讨论和揭示了该黄铁矿的成因。岩石矿物学研究结果显示黄铁矿具有多种赋存形式,呈零星或集合体充填于膏溶孔和溶蚀孔洞中,或与层状硬石膏相伴生;硫同位素地球化学分析结果显示,黄铁矿的δ34S值介于10. 50‰~24. 00‰之间,平均值为17. 33‰。盆地东南部具备薄层硬石膏、高温驱动和充足的烃类气体等热化学硫酸盐还原作用发生的条件,结合其产状证据认为黄铁矿形成于热化学硫酸盐还原作用。黄铁矿出现的地层中Fe含量较高,介于3 387. 50×10~(-6)~23 112. 50×10~(-6)之间,平均值为13 233. 33×10~(-6),为黄铁矿的形成提供了物质来源。盆地东南部多产低含H2S天然气,研究认为黄铁矿的形成是造成该地区H2S含量较低的主要原因。  相似文献   

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