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1.
以亚甲基蓝溶液为模型污染物,在超声波芬顿法协同作用下对亚甲基蓝染料废水的降解作用进行了研究,考察了反应时间、H2O2用量、溶液pH值、Fe^2＋的浓度等因素对亚甲基蓝溶液降解的影响。结果表明,超声波单独降解亚甲基蓝溶液脱色效果不明显,超声波协同H2O2降解亚甲基蓝,加入30%H2O26mL,脱色率约45.80%;溶液pH2.80,Fe^2＋浓度为30mmol/L时,超声波芬顿法协同降解甲基蓝180min,脱色率达92.70%。试验证明,超声波芬顿法是一种降解亚甲基蓝的有效方法。 相似文献
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碳酸盐矿物的阴极发光性主要受其Mn^2＋和Fe^2＋含量,以及Mn^2＋／Fe^2＋值的综合控制,但Mn^2＋／Fe^2＋值的控制作用强一些。研究中充填裂缝的方解石胶结物样品主要采自北京西山寒武系和奥陶系的碳酸盐岩地层中。此外,还从北京石花洞中采集了现代溶洞的石笋样品。样品的阴极发光强度可分为不发光、暗、中等和亮,阴极发光颜色也相应地分为不发光、橙红色、橙黄色和亮黄色。通过对野外露头样品进行电子探针研究,测定其中的Mn^2＋和F^2＋’的含量,并结合样品的阴极发光颜色和强度,得出Mn^2＋含量要在0．01％以上,Fe^2＋含量至少在0．8％以下,Mn^2＋／Fe^2＋在0．05以上,方解石胶结物才能发光。经研究发现,充填裂缝中方解石胶结物的阴极发光性与Mn^2＋和Fe^2＋含量,以及Mn^2＋／Fe^2＋值之间存在如下关系：不含Mn^2＋,Fe^2＋微量,Mn^2＋／Fe^2＋为0时,不发光;0．05〈Mn^2＋Fe^2＋〈0．2时,发光强度暗,发光颜色为橙红色;0．2〈Mn^2＋／Fe^2＋〈2时,发光强度中等,发光颜色为橙黄色;Mn^2＋／Fe^2＋〉2时,发光强度亮,发光颜色为亮黄色。 相似文献
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太湖北部沉积物中铁硫的地球化学特征研究 总被引：6，自引：1，他引：5
选择太湖北部柱状沉积物为研究对象,对沉积物及间隙水中铁硫的地球化学特征进行了研究。结果显示．间隙水中Fe^2＋的平均浓度是S^2-平均浓度的82倍,其值为9．6～270．5μmol／L。这说明沉积物中是以Fe^3＋的还原为主,而非SO4^2-。沉积物中还原性无机硫以黄铁矿为主,其次为AVS,最后为单质硫。沉积物中的Fe^2＋的浓度均高于其他形态的铁,约占总铁含量的30％～40％。活性铁的浓度为109．86～208．16μmol／g,仅占总铁的20％左右。沉积物各层中与硫结合的铁仅占总铁的0．12％～2．35％,占活性铁的0．39％～8．36％,通过分析铁硫之间的关系并结合蓝藻爆发的时间推断,铁硫化合物的生成不是PO4^3-释放的原因。太湖北部沉积物中Fe—S及P-S之间相互关系较弱。 相似文献
4.
氧化亚铁硫杆菌与毒砂相互作用的阶段性及其机理研究 总被引：2，自引：0，他引：2
设计了毒砂的生物氧化和化学氧化两组对比实验,并对反应35d的溶液化学、固相产物成分和矿物表面元素化合态变化进行了分析,以说明氧化亚铁硫杆菌（A．ferrooxidans）与毒砂的相互作用机理。研究发现,毒砂的生物氧化过程随A．ferrooxidans菌生长规律分为三个阶段：（1）反应前7d,生物氧化作用还很弱,以自然氧化反应为主;（2）反应8～21d,生物氧化反应开始发生,细菌进入迟缓生长期;（3）反应22～35d,细菌处于对数生长期,生物氧化作用强烈。由离子浓度变化规律反映,前两个阶段生物氧化速率低于化学氧化,第三阶段起生物氧化速率高于化学氧化。细菌生长受溶液累积的As抑制,A．ferrooxidans菌能促进As和Fe形成砷酸铁沉淀,以降低As的抑制作用。毒砂表面高价态元素的比例随细菌生长和溶液Fe离子浓度的升高而增大,生物氧化第三阶段毒砂表面高价态元素的比例高于化学氧化。氧化过程中毒砂表面覆盖中间氧化产物S^0和As2S3沉积层,对比化学氧化,Aferrooxidans菌能不断把Fe^2＋氧化成Fe^3＋,促进毒砂表面中间产物氧化,并间接氧化毒砂。 相似文献
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6.
Qianli XIE Peter Dillon Lewis Molot 《中国地球化学学报》2006,25(B08):204-204
In aquatic environment, iron redox reaction may occur through a） microbial activity and b） photo-chemistry. Iron chemistry plays a significant role in the health of aquatic ecosystems. For example, Fe^2＋ is more mobile than Fe^3＋. Iron can be bound to dissolved organic carbon （DOC）, and when Fe^2＋ is oxidized to Fe^3＋ （biotically or abiotically）, Fe is precipitated and induce co-precipitation of the DOC. Furthermore, iron is a major nutrient to aquatic organisms. Because Fe^2＋ is more bioavailable than Fe^3＋, iron redox chemistry can be a controlling factor in biological production, such as algae bloom which can be a public health concern. Experiments have shown that Fe redox reactions, biotically or abiotically, can generate significant Fe isotope fraction among different Fe species. Accordingly, analysis of Fe isotope composition of phytoplanktons can be a valuable tool in studying Fe dynamics in ecosystems. Precise measurement of Fe isotope, however, presents some challenges. Recent advances in mass spectrometry, specifically high resolution MC-ICP-MS, allow measurement of Fe isotopes free of interferences. 相似文献
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采用（斜长石＋黑云母＋石英）这三种单矿物组合与1mol/L NaCl或0．5mol/L NaCl 0.5mol/L NaHCO3溶液在450－250℃和50MPa条件下反应7d。实验表明，反应后流体pH值发生了变化，NaCl介质向酸性变化，N aCl NaHCO3介质向中性转化。溶液中K,Ca,Mg,Fe和Au量也随之发生变化。矿物表面发生溶解和离子置换等反应。斜长石表面形成钠长石反应边，黑云母变色，石英重结晶，反应器皿金管中的金被溶解后在金管壁和黑云母表面重结晶，黑云母周边出现红色Fe2O3，在450℃的NaCl介质中，金含量可达1070μg/g，但随温度下降迅速减低，在NaCl NaHCO3介质中，金含量较低，显著，金的活化迁移和富集与Cl,pH,Fe^3 /Fe^2 密切相关，这中金起到示踪作用，显示出金在水／岩反应中的原电池效应。 相似文献
8.
研究了电气石微粉吸附水中Cu2＋、Pb2＋、Zn2＋的过程,讨论了吸附时间、粒度、用量和pH值等因素对吸附效果的影响,分析了电气石对含Cu2＋、Pb2＋、Zn2＋废水的吸附机理。电气石加工成超细粉体时,表面产生大量的不饱和键,在溶液中与水配位,使水发生解离生成羟基化表面,将重金属离子吸附到晶体负极,使局部金属离子浓度增高与电气石表面羟基离解而产生的氢氧根离子发生反应,形成各种沉淀或碱式盐析出,直到溶液中各种离子浓度达到平衡时为止。提出了凡是氢氧化物难溶于水的金属离子,理论上都可以使用电气石微粉进行吸附净化处理的观点。研究结果表明,电气石微粉对Cu2＋、Pb2＋、Zn2＋有较好的吸附效果。 相似文献
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2010年以来,对研究区内水文地质背景及不同层位水质化学测试样品数据分析研究,重点阐述了微量元素F e3＋的富集与含水介质岩性、地下水的酸碱度、地层含水性和氧化还原环境的关系,认为地下水中F e3＋富集赋存的最有利的环境是变质岩类地层;碳酸盐岩和碎屑岩中水化学类型 HCO3 Ca型水分布最广,碳酸盐岩的地下水中Fe^3＋平均含量最低;变质岩中硫酸型（包括复合型）的地下水中 Fe^3＋的平均含量最高,对 Fe^3＋的行为呈正相关关系。地下水中F e3＋含量赋存具以副井及其外围地区为中心高浓度分带性。 相似文献
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生物样品用艾斯卡熔剂分解，强酸性阳离子交换树脂静态吸附分离大量Na^＋等阳离子后，采用Fe^3＋-SCN^--NO2^-催化体系分光光度法测定痕量碘。通过正交实验确定了催化反应的最佳实验条件。方法检出限（6s）为0．13μg／g，方法精密度（RSD，n=12）为3．69％～8．28％。用国家一级生物标准物质进行验证，测定值与标准值相符。 相似文献
11.
酸性矿山废水中生物成因次生高铁矿物的形成及环境工程意义 总被引：10，自引：1，他引：9
酸性矿山废水(acid mine drainage,AMD)是一类pH低并含有大量有毒金属元素的废水。AMD及受其影响的环境中次生高铁矿物类型主要包括羟基硫酸高铁矿物(如黄铁矾和施威特曼石等)和一些含水氧化铁矿物(如针铁矿和水铁矿等),而且这些矿物在不同条件下会发生相转变,如施氏矿物向针铁矿或黄铁矾矿物相转化。基于酸性环境中生物成因次生矿物的形成会"自然钝化"或"清除"废水中铁和有毒金属这一现象所获得的启示,提出利用这些矿物作为环境吸附材料去除地下水中砷,不但吸附量大(如施氏矿物对As的吸附可高达120mg/g),而且可直接吸附As(III),还几乎不受地下水中其他元素影响。利用AMD环境中羟基硫酸高铁矿物形成的原理,可将其应用于AMD石灰中和主动处理系统中,构成"强化微生物氧化诱导成矿-石灰中和"的联合主动处理系统,以提高AMD处理效果和降低石灰用量。利用微生物强化氧化与次生矿物晶体不断生长的原理构筑生物渗透性反应墙(PRB)并和石灰石渗透沟渠耦联,形成新型的AMD联合被动处理系统,这将有助于大幅度增加处理系统的寿命和处理效率。此外,文中还探讨了上述生物成因矿物形成在AMD和地下水处理方面应用的优点以及今后需要继续研究的问题。 相似文献
12.
As(Ⅴ)对嗜酸性氧化亚铁硫杆菌混合培养物氧化性能的影响 总被引：2，自引：1，他引：1
通过对pH、Eh、溶液中Fe2+浓度的定期监测以及对实验结束时生成沉淀的XRD、SEM和元素能谱扫描等手段,对比研究了不同初始浓度的As(Ⅴ)对Fe2+的化学氧化和嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)氧化的影响, 同时就As(Ⅴ)在实验体系中固液相之间的分配行为进行了分析.结果表明,Fe2+的化学氧化速率极低,最终氧化率低于8%,As(Ⅴ)的浓度对Fe2+的化学氧化没有影响.有A. ferrooxidans的实验体系,100 mg/L As(Ⅴ)对Fe2+的氧化具有一定的促进作用.当As(Ⅴ)浓度为500 mg～1 g/L时,Fe2+的氧化率在约60 h左右即可达到100%;但4g/L的As(Ⅴ)则会明显抑制Fe2+的氧化,Fe2+的完全氧化大约需要106 h.体系中初始的100 As/(As+S)(摩尔比)会对沉淀物的物相及结晶程度造成一定影响.As(Ⅴ)浓度为0 g/L时,微生物体系中生成的固体沉淀物黄钾铁矾的特征峰明显,随着As(Ⅴ)浓度的提高,沉淀物的结晶程度逐步下降,至4 g/L时沉淀物全部为无定形.元素能谱扫描检测到有大量的As(Ⅴ)存在于固体沉淀物中,表明在Fe2+的氧化过程中,As(Ⅴ)可能会以吸附或共沉淀的形式被固定在固相沉淀物中,这为酸性矿坑水(AMD)地区As(Ⅴ)污染的治理提供了重要的参考. 相似文献
13.
《矿物学报》2013,(Z1)
China has accumulated massive fine grained copper mine tailings stocks because of the past mining activities in this area. The tailings contain a variety of heavy metals, and the mass percent of Cu, which is one of the main contaminants in tailings, is up to 0.2601% (analysis by XRF). The Cu can pollute soil and groundwater by rain leaching in the form of Cu(Ⅱ), furthermore ,the fine grained copper-ore-tailings can contaminant larger area by wind for its small granularity ( < 74 μm). The main cause of weathering of mine tailings is due to oxidative dissolution of sulfides. Microorganisms, such as Acidithiobacillus ferrooxidans, play an important role in weathering. These bacteria attach to exposed to mineral surfaces by excreting extracellular polymers and oxidize the sulfide mineral. Some of these bacteria also oxidize Fe2+ to Fe3+ which can chemically oxidize sulfide minerals. These reactions produce voluminous quantities of acid mine drainage and heavy metals which are harmful to the environment and human healthy. This study aims at finding the weathering effects of A. ferrooxidans to Cu(II) pollution of fine grained copper mine tailings, and our experiment applied indigenous A. ferrooxidans FJ-01 to leach the tailings. The optimum test parameters were obtained using shaking flask experiment and SEM observation under the following experimental conditions: 39 days residence time, pulp density 1%-15% (1%, 5% and 15%), 30℃, 120 rpm, pH between 1-3 and redox potential between 400-650 mV. The test results show that the leaching rate of Cu reached 43.1% when the pulp density was 1% after 33 days and kept invariant till the end of the test. In addition, the leaching rate of Cu will decrease as the increase of pulp density, and the maximum rate of 15% pulp density was only 12.5%. From the SEM, it can be seen that the fine grain of tailings flocculated to conglobation under the action of bacterial leaching. 相似文献
14.
Zinc extraction from Iranian low-grade complex zinc–lead ore by two native microorganisms: Acidithiobacillus ferrooxidans and Sulfobacillus 总被引：2，自引：0，他引：2
S.M. Mousavi S. Yaghmaei M. Vossoughi A. Jafari R. Roostaazad 《International Journal of Mineral Processing》2006,80(2-4):238-243
A mesophilic iron oxidizing bacterium, Acidithiobacillus ferrooxidans, has been isolated (33 °C) from a typical, chalcopyrite concentrate of the Sarcheshmeh copper mine in the region of Kerman located in the south of Iran. In addition, a thermophilic iron oxidizing bacterium, Sulfobacillus, has been isolated (60 °C) from the sphalerite concentrate of Kooshk lead and zinc mine near the city of Yazd in the center point of Iran. Variation of pH, ferrous and ferric concentration on time and effects of some factors such as temperature, cell growth, initial ferrous concentration and pH on bioleaching of low-grade complex zinc–lead ore were investigated. The results obtained from bioleaching experiments indicate that the efficiency of zinc extraction is dependent on all of the mentioned variables; especially the temperature and initial Fe(II) concentration have more effect than other factors for these microorganisms. In addition, results show that the maximum zinc recovery was achieved using a thermophilic culture. Zinc dissolution reached 58% with Sulfobacillus while it was 51% with A. ferrooxidans at pH = 1.5, initial Fe(II) concentration = 7 and 9 g/L for A. ferrooxidans and Sulfobacillus, respectively, after 30 days. 相似文献
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Fe(Ⅲ)供应速率对无定型施氏矿物形成的影响 总被引：2，自引：0，他引：2
施氏矿物(schwertmannite)已被证实是一种具特异性能的重(类)金属吸附新材料。但在直接由Fe3+或用强氧化剂氧化Fe2+合成该矿物时,常因夹有黄铁矾类物质而降低产品纯度。通过模拟FeSO4-K2SO4-H2O临界成矾体系,发现在嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)作用下存在无定型施氏矿物和晶型黄钾铁矾的合成反应竞争,其中Fe3+供应速率是一个影响铁矿物形成的重要因素,较低的Fe3+供应可以抑制K+的利用,这种变化趋势对无定型施氏矿物合成是有利的。当存在少量K+等成矾导向离子时,可通过合理调低Fe3+供应速率,有利于溶液中Fe3+平缓释放,改善施氏矿物纯度,这为A.ferroxidans菌生物法中直接使用无机盐培养基合成施氏矿物提供了可能。 相似文献
17.
Tariq M. Bhatti Jerry M. Bigham Antti Vuorinen Olli H. Tuovinen 《International Journal of Mineral Processing》2011,98(1-2):30-34
The purpose of this study was to examine structural alterations of finely ground phlogopite, a trioctahedral mica, when exposed to acid, iron- and sulfate-rich solutions typical of bioleaching systems. Phlogopite suspensions were supplemented with ferrous sulfate and incubated with iron- and sulfur-oxidizing bacteria (Acidithiobacillus ferrooxidans) at 22 °C. As bacteria oxidized ferrous iron, ferric iron thus formed partially precipitated as K-jarosite. K-jarosite precipitation was contingent on the preceding ferrous iron oxidation by bacteria and the release of interlayer-K from phlogopite. This chemically and microbially induced weathering involved alteration of phlogopite to a mixed layer structure that included expansible vermiculite. The extent of phlogopite weathering and structure expansion varied with duration of the contact, concentration of ferrous iron and phlogopite, and the presence of monovalent cations (NH4+, K+, or Na+) in the culture solution. NH4+ and K+ ions (100 mM) added to culture suspensions precipitated as jarosite and thereby effectively prevented the loss of interlayer-K and structural alteration of phlogopite. Additional Na+ (100 mM) was insufficient to precipitate ferric iron as natrojarosite and therefore the precipitation was coupled with interlayer-K released from phlogopite. When ferrous iron was replaced with elemental sulfur as the substrate for A. ferrooxidans, the weathering of phlogopite was based on chemical dissolution without structural interstratification. The results demonstrate that iron oxidation and the concentration and composition of monovalent ions can have an effect on mineral weathering in leaching systems that involve contact of phlogopite and other mica minerals with acid leach solutions. 相似文献
18.
一价阳离子和水溶性有机质对生物沥浸中次生铁矿物形成的影响 总被引：2，自引：0，他引：2
在嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)作用下,污泥生物沥浸体系中常会有次生铁矿物形成,这些矿物对污泥脱水和重金属溶出有重要影响。本研究模拟生物沥浸体系,考察了一价阳离子(K+、NH4+、Na+)和污泥DOM(dissolved organic matter)对次生铁矿物形成的影响。结果表明,一价阳离子生成次生黄铁矾类矿物的能力迥异,其中K+的成矾能力最强,120 mmol/L NH4+和80 mmol/L Na+会抑制体系中黄钾铁矾形成。在1.6 mmol/L K+-120 mmol/L NH4+-40 mmol/L Na+和1.6 mmol/L K+-80 mmol/L NH4+-80 mmol/L Na+两个处理所得矿物的结晶度均低于1.6 mmol/L K+-80 mmol/L NH4+-40 mmol/L Na+处理所得矿物的结晶度。另外,在50 mg/L DOM(以DOC计)存在的生物氧化体系,Fe2+最大氧化速率为4.96 h-1,比没有DOM存在时降低48.1%,矿物结晶度也明显低于后者。可见,过高的一价阳离子和DOM含量会影响A.ferrooxidans菌生理生化活性,降低Fe2+氧化速率,继而影响Fe3+供应,使微环境中的黄铁矾形成动力发生改变,最终在一定程度上影响了次生铁矿物的形成。 相似文献
19.
氧化亚铁硫杆菌对黄铁矿的氧化作用初探 总被引：6，自引：0，他引：6
利用自行分离培养的氧化亚铁硫杆菌(A.f菌)为实验菌株,比较了黄铁矿化学氧化和生物氧化过程中溶液铁离子浓度的变化。研究发现,Fe3 对黄铁矿的氧化速率较低,而在细菌的作用下可以不断将Fe2 氧化成Fe3 使得黄铁矿的氧化速率明显加快,因此生物氧化具有更高的效率。经过44 d的氧化之后,利用扫描电镜对氧化后的黄铁矿表面进行了显微观察,发现Fe3 的化学氧化主要集中在化学键较弱的晶棱部位,而在生物氧化的情况下矿物表面充满了密集的溶蚀坑,溶蚀坑的形状与A.f菌的外形非常相近,且规则排列。这说明A.f菌能够吸附到黄铁矿表面,并且这种吸附具有定向排列的特点。 相似文献
20.
Xiaofen Yang Hongmei Wang Linfeng Gong Hima Hassane Zhengbo Jiang 《Frontiers of Earth Science》2009,3(2):221-225
Fe2+ oxidation by Acidithiobacillus ferrooxidans in pure and mixed cultures was investigated in batch cultures in the presence of arsenate. The pH value was periodically
monitored and Fe2+ content was analyzed by the 1,10-phenanthroline method. ICP-AES was employed for the analysis of As(V) concentration in the
solution phase. Precipitates were collected and analyzed by X-ray diffraction. Slight enhancement of iron bio-oxidation was
observed in mixed cultures with the two greatest As(V) concentrations (1.0 and 5.0 mg/L As), which were enriched from sediment
samples in an abandoned copper mine site. As(V) concentrations decreased with time, indicating either the co-precipitation
with or the adsorption by jarosite, the major sink of solid phase. Our data suggest that biogenically synthesized jarosite
may play an important role in the attenuation of soluble arsenate in natural aquatic environments. 相似文献