EFFECT OF SULPHATE-REDUCING BACTERIA ON ELECTRO CHEMICAL CORROSION BEHAVIOR OF 16Mn STEEL IN SEA MUD

The effect of sulfate reducing bacteria (SRB) on electrochemical corrosion behavior of 16Mn steel, and galvanic corrosion behavior of the steels in the juncture area between bacterial and bacteria free sea mud was studied in laboratory under simulated conditions. Sea mud dense with SRB was taken from the Qingdao beach. Part of the sea mud was sterilized and the rest was kept in the original condition. The sterilized and original sea mud was put respectively into two plastic testing troughs electrically connected by an agar potassium chloride salt bridge. Galvanic and non galvanic 16Mn steel samples were put into the trough at the same intervals. The SRB number measured by the MPN tri tube method was about 2.4×10 5 per 100 g mud and was kept basically the same during the experimental period. The ρ, pH, eH, T, S (salinity) were measured simultaneously. The galvanic current was measured with zero resistance galvanometer and the corrosion rate was measured with the weight loss method.The results showed that (1) the corrosion rate of 16Mn steel in bacterial sea mud was 4.0 times that in bacteria free sea mud; (2) galvanic corrosion occurs between steel samples buried in different (bacterial and bacteria free) sea mud. The steel sample in the bacterial sea mud was the anode of a galvanic couple and had higher corrosion rate than that of the non galvanic sample. The existence of the galvanic couple increased the corrosion rate of the sample in bacterial sea mud by 4.1%.

Treatment of simulated wastewater from in situ leaching uranium mining by zerovalent iron and sulfate reducing bacteria

Batch and column experiments were conducted to determine whether zerovalent iron (ZVI) and sulfate reducing bacteria (SRB) can function synergistically and accelerate pollutant removal. Batch experiments suggest that combining ZVI with SRB can enhance the removal of U(Ⅵ) synergistically. The removal rate of U(Ⅵ) in the ZVI+SRB combining system is obviously higher than the total rate of ZVI system and SRB system with a difference of 13.4% at t=2 h and 29.9% at t=4 h. Column experiments indicate that the reactor filled with both ZVI and SRB biofilms is of better performance than the SRB bioreactor in wastewater basification, desulfurization and U(Ⅵ) fixation. The results imply that the ZVI+SRB permeable reactive barrier may be a promising method for treating subsurface uranium contamination.

Molecular Characterization of Sulfate-Reducing Bacteria Community in Surface Sediments from the Adjacent Area of Changjiang Estuary

Sulfate-reducing bacteria(SRB),which obtain energy from dissimilatory sulfate reduction,play a vital role in the carbon and sulfur cycles.The dissimilatory sulfite reductase(Dsr),catalyzing the last step in the sulfate reduction pathway,has been found in all known SRB that have been tested so far.In this study,the diversity of SRB was investigated in the surface sediments from the adjacent area of Changjiang Estuary by PCR amplification,cloning and sequencing of the dissimilatory sulfite reductase beta subunit gene(dsr B).Based on dsr B clone libraries constructed in this study,diversified SRB were found,represented by 173 unique OTUs.Certain cloned sequences were associated with Desulfobacteraceae,Desulfobulbaceae,and a large fraction(60%) of novel sequences that have deeply branched groups in the dsr B tree,indicating that novel SRB inhabit the surface sediments.In addition,correlations of the SRB assemblages with environmental factors were analyzed by the linear model-based redundancy analysis(RDA).The result revealed that temperature,salinity and the content of TOC were most closely correlated with the SRB communities.More information on SRB community was obtained by applying the utility of Uni Frac to published dsr B gene sequences from this study and other 9 different kinds of marine environments.The results demonstrated that there were highly similar SRB genotypes in the marine and estuarine sediments,and that geographic positions and environmental factors influenced the SRB community distribution.

Effect of Sulfate-reducing Bacteria on Corrosion Behavior of Mild Steel in Sea Mud

微生物学地影响的腐蚀( MIC )是在它是的海泥 environment.Therefore 下面埋葬的很严重的腐蚀 forconstructions 对很重要在海 mud.In 执行海洋的钢的腐蚀行为的 theinvestigation 这份报纸，海泥里的低碳钢的腐蚀行为上的效果 减少ofsulfate 细菌( SRB )被 weightloss 学习，双分隔空间的房间，电子探查微量分析( EPMA )，传播 electronmicroscopy ( TEM )

Corrosion and Electrochemical Behavior of 316L Stainless Steel in Sulfate-reducing and Iron-oxidizing Bacteria Solutions

Corrosion and electrochemical behavior of 316L stainless steel was investigated in the presence of aerobic iron-oxidizing bacteria IOB and anaerobic sulfate-reducing bacteria SRB isolated from cooling water systems in an oil refinery using electrochemical measurement, scanning electron microscopy SEM and energy dispersive atom X-ray analysisEDAX. The results show the corrosion potential and pitting potential of 316L stainless steel decrease distinctly in the presence of bacteria, in comparison with those observed in sterile medium under the same exposure time. SEM morphologies have shown that 316L stainless steel reveals no signs of pitting attack in the sterile medium. However, micrometer-scale corrosion pits were observed on 316L stainless steel sur- face in the presence of bacteria. The presence of SRB leads to higher corrosion rates than IOB. The interactions between the stainless steel surface, abiotic corrosion products, and bacterial cells and their metabolic products in- creased the corrosion damage degree of the passive film and accelerated pitting propagation.

Synthesis of Chlorinated Bicyclic Adduct as Biocids for Sulfate-Reducing Bacteria

Synthesis of bicyclic systems containing chlorine atoms, and/or ether groups in aromatic rings can be con- sidered as an important method for building bicyclic system and production of new adducts. One of the most important types in the cycloaddition reaction is the Diels-Alder reaction (1,4 cycloaddition). In the present investigation a new ether of allylic type (dienophile) p-allyl bromo phenol was prepared and its structure was confirmed by molecular weight determination, refractive index, infrared spectra, and density. A new adduct was obtained by means of 1,4 cycloaddition reaction of hexachlorocyclopentadiene (HCP) and the new pre- pared dienophile. The reaction takes place without using solvent, catalysts, or elimination of any compound. The effect of variations in temperature, initial molar ratio and reaction duration were studied to determine the optimum conditions of the reaction. The optimum conditions reached were reaction temperature recorded 140?C, initial molar ratio diene: dienophile was 3:1 and the reaction duration time reached 6 h. Under these optimum conditions the maximum yield was 78%. The new adduct revealed very high biological effect as sulfate-reducing bacteria (SRB).

Model identification with BPNN on restrictive ecological factors of SRB for sulfate-reduction

The model of back-propagation neural network (BPNN) was presented to demonstrate the effect of restrictive ecological factors, COD/SO 4 2- ratio, pH value, alkalinity (ALK) and SO 4 2- loading rate (Ns), on sulfate reduction of Sulfate Reducing Bacteria (SRB) in an acidogenic sulfate reducing reactor supplied with molasses as sole organic carbon source and sodium sulfate as electron acceptor. The compare of experimental results and computer simulation was also discussed. It was shown that the method of BPNN had a powerful ability to analyze the ecological characteristic of acidogenic sulfate reducing ecosystem quantitatively.

SRB-生物硫铁复合材料对废弃煤矿地下水的修复研究

酸性矿山废水(AMD)中含有高浓度的硫酸盐和金属离子,对矿山生态环境造成了严重的危害。硫酸盐还原菌(SRB)可以将SO_(4)^(2-)还原为S2-,沉淀金属离子,并生成生物硫铁,其处理效率较高。文章利用农业废弃物秸秆制备SRB的缓释碳源,考察了不同形式的碳源条件下SRB对酸性矿山废水特征污染组分的处理效果,并结合SRB原位生成的生物硫铁包覆颗粒,制备得到SRB-生物硫铁复合材料,通过批量实验和动态柱实验考查SRB-生物硫铁复合材料对高浓度模拟废水和实际矿井水的处理效果。结果显示:在pH为5.5时,将秸秆渣作为游离SRB的碳源是可行的,但与秸秆渣相比,秸秆生物炭的处理效率明显更高,将秸秆生物炭与乳酸钠结合制备的SRB碳源,激活SRB的时间更短,12 h内对SO_(4)^(2-)和Fe^(2+)的去除率分别达到了59.25%和79.56%。在此实验范围内,随着生物炭投加量的增大,去除效率逐渐提高,在pH为4.5~6.5的范围内,体系初始pH对SRB反应体系的处理效果影响不大。SRB-碳源与生物硫铁包覆颗粒结合后对高浓度的SO_(4)^(2-)和Fe^(2+)模拟废水能保持高效且持久的反应活性。动态柱实验表明SRB-生物炭-生物硫铁复合材料对酸性矿井水的特征污染指标有明显的修复效果,出水水质的大部分指标可满足地下水III类标准,运行15 d后仍能保持稳定的修复效果。

Effects of Sulphate-reducing Bacteria on Corrosion Behaviour of 2205 Duplex Stainless Steel

The effects of sulphate-reducing bacteria （SRB） on the 2205 duplex stainless steel in the sea water and oil industry environments were studied by electrochemical impedance spectroscopy （EIS）, potentiodynamic polarization and microorganism analysis. The results showed that the detected SRB was the non-spore bacillus of about 0.8μm×（1.8--2.2）μm in size and the content of S was about 7. 59% in the corrosion products. SRB contributed to the corrosion evolution which caused the corrosion failure of 2205 duplex stainless steel pipe in the liquid hydrocarbon cooler. During the corrosion process, the produced H2S could significantly influence the anodic process and finally accelerate the corrosion. SEM observation indicated that the distribution of SRB on the surface of 2205 duplex stainless steel was nonuniform. X ray photoelectron spectroscopy analysis revealed that the surface film was composed of Cr2O3, MoO3 , FeS, FeS2, Fe（OH）2 and FeO after immersing the sample in the SRB medium for 14 d.

一株硫酸盐还原菌DSRBa的分离鉴定及特性分析

从内循环厌氧反应器颗粒污泥中分离、纯化得到一株硫酸盐还原菌命名为DSRBa,经形态和基于16SrDNA序列分析,该菌株归属于脱硫弧菌属(Desulfovibrio)。分别以甲酸钠、乙醇、乳酸钠、葡萄糖等为碳源,以硫酸盐、硫代硫酸盐、亚硫酸盐、单质硫为硫源,研究了不同温度、pH及不同硫酸根浓度对该菌株的影响。结果表明,菌株最适宜生长温度为30～35℃,最佳生长pH为7.0,无需绝对严格厌氧,当溶液中氧化还原电位(ORP)≤-40mV时,该菌株能较好生长,且生长4d后使溶液内氧化还原电位值达到-380mV,随后溶液内氧化还原电位基本保持不变。当系统内乳酸钠和酵母提取物浓度分别为3.5g·L-1和1g·L-1时,硫酸根浓度在1～4.5g·L-1范围对菌株生长无明显影响,且当SO24-浓度≤3g·L-1时,菌株生长4d对硫酸根的去除率达到90%以上。

生物竞争技术防治油田采出水中SRB引起的腐蚀

新疆彩南油田产出水富含SRB、NRB及硫酸根离子,生产系统腐蚀严重。研究了利用SRB和NRB之间的生物竞争防止SRB引起的腐蚀的方法。在厌氧培养基中加入化学处理剂,在40℃培养7天,由N80钢片腐蚀速率确定了化学处理剂的适宜加量：现用杀菌剂（1227＋戊二醛）为80 mg/L,SRB抑制剂（硝酸铵＋亚硝酸钠）为1 mg/L,缓蚀剂ZC-503为20 mg/L。在彩南C2104井产出水样中加入1%磷酸氢二铵、0.1%酵母膏、适宜加量的一种或一组化学处理剂,在40℃密闭培养不同时间（4-96小时）后测SRB、NRB菌数和S2-浓度,培养120小时后测钢片腐蚀速率,结果如下：加入抑制剂可抑制SRB生长,促进NRB生长,防止S2-生成,使腐蚀速率由0.102 mm/a降至0.064 mm/a;加入缓蚀剂不影响两种菌的生长,可推后S2-的生成,使腐蚀速率降至0.038 mm/a;同时加入抑制剂和缓蚀剂可完全抑制SRB生长,防止S2-生成,促进NRB生长,使腐蚀速率降至0.035 mm/a。建议彩南油田生产系统采用这种低费用的生物竞争和化学缓蚀结合技术防治SRB引起的腐蚀。

游离和固定化SRB污泥处理含锌废水比较研究

采用聚乙烯醇(PVA)-硫酸铵包埋法对硫酸盐还原菌(SRB)进行固定化处理。以含锌废水为处理对象,利用内聚营养源固定化小球与游离污泥做对比实验,考察硫酸根去除率、锌离子去除率、出水COD值等因素,并借助EDX分析小球内部锌离子含量。实验结果表明,采用内聚营养源固定化小球,硫酸根去除率为55.7%,锌离子去除率达98%,出水COD<100mg/L,进行多次循环实验,出水锌离子浓度仍达到污水综合排放二级标准;采用游离污泥,硫酸根去除率为46.1%,锌离子去除率为98.2%,出水COD1800mg/L以上,用于二次处理废水,锌离子去除率仅为60.4%。固定化小球循环处理废水四次后,每克固定化小球内部锌离子含量为0.04364mg。

海泥中SRB对A_3钢电偶效应的影响

在室内模拟条件下研究了在海泥中硫酸盐还原菌 (SRB)对A3钢电偶效应的影响。实验在两个大型塑料槽中进行。A3钢样尺寸为 2 0cm× 1 0cm× 0 .3cm ,海泥中SRB的含量用MPN三管计数法进行测定 ;电导率、pH、氧化还原电位、泥温和盐度等参数用SY - 5型电导 -pH/mV -温度计进行测量 ;用失重法测量腐蚀速度 ;用零电阻表测量电偶电流。试验共进行 2 61d。SRB含量随时间的变化基本保持恒定。在电偶条件下A3钢在灭菌泥和有菌泥中的腐蚀速度分别为0 0 0 77mm/a和 0 0 4 9mm/a,在非电偶条件下A3钢在灭菌泥和有菌泥中的腐蚀速度分别为 0 0 0 89mm/a和 0 0 4 4mm/a。A3钢在有菌泥和无菌泥中的样板之间的电偶电流随时间的变化幅度在2 5μA左右 ,且有方向逆转现象。试验结果表明 ,在有菌泥中A3钢的腐蚀速度是无菌泥中的 5 5倍 ,说明SRB在海泥腐蚀中有重要作用。埋在相邻的有菌海泥和无菌海泥的试样之间都发生了电偶腐蚀。处在有菌海泥中的钢样为电偶对的阳极 ,处在无菌海泥中的钢样为电偶对的阴极。在实验期间内电偶效应对试样的加速作用为 1 1 .4%。

内聚营养源SRB固定化交联剂的选择及对含锌废水的处理

以聚乙烯醇为包埋介质,对硫酸盐还原菌(SRB)进行固定化处理;以含锌废水为处理对象,考察不同交联剂对成球性能影响、营养源内聚效果、硫酸盐还原效果、锌离子去除率和出水COD(化学需氧量)等因素。研究结果表明:最佳交联剂为40%(NH4)2SO4和2%CaCl2;采用该交联体系制得固定化小球,每克小球内聚33.11mg乳酸钠,硫酸根还原率为53.5%,锌离子去除率可达到98%,出水COD低于100mg/L;固定化小球经过4次循环试验,出水锌离子浓度仍达到污水综合排放二级标准。

硫酸盐还原过程中SRB的限制性生态因子的BP神经网络建模与仿真

利用BP神经网络对产酸脱硫反应器 (专利设备 ,ZL :982 40 80 1 3)处理高浓度硫酸盐废水时硫酸盐还原菌 (SRB)的限制性生态因子 (COD SO2 -4 比、pH值、ALK、SO2 -4 负荷率 )进行建模与仿真 ,从而实现了多变量函数关系的映射与泛化 。

硫酸盐还原菌利用玉米发酵液为碳源还原地下水中的硫酸盐

将玉米发酵液作为微生物硫酸盐还原体系的碳源,可大幅降低还原成本,对实现硫酸盐废水经济、高效处理具有重要意义。探究了复合碳源比例、碳硫比(C S)和pH等对硫酸盐还原菌(SRB)还原硫酸盐的影响。结果表明:在初始SO_(4)^(2-)浓度为(1000±50)mg L时,5种复合碳源比例均能获得较好的硫酸盐还原效果,剩余SO_(4)^(2-)浓度均小于地下水质量标准Ⅳ类水质350 mg L要求;当初始C S=0~3.5时,随C S比升高,SRB的硫酸盐还原速率增加,但碳源的硫酸盐还原利用效率下降;在初始pH接近7.0时SRB硫酸盐还原活性最佳。反应体系pH和ORP值的变化可准确指示细菌活性变化。

SRB以油菜秸秆为基质处理酸性矿山排水

文章以乙酸钠作为对照底物,研究分析了在不同铜离子质量浓度下,硫酸盐还原菌(sulfate-reducingbacteria,简称SRB)以油菜秸秆为基质处理酸性矿山排水的过程及其主要影响因素。结果表明:当初始铜离子质量浓度分别为0、6.4、12.8、32.0、48.0mg/L时,反应初期各体系内的pH值从5.0迅速升高到7.0～7.5,实验结束后SO42-去除率都超过了94%,反应器中TOC质量浓度在实验开始几天内均先上升,并在达到峰值后迅速下降;而重金属存在时,以乙酸钠为底物的反应器内SO42-还原速率及去除效率都受到显著抑制。研究还表明,秸秆的吸附作用降低了铜离子对SRB的毒性作用。因此,油菜秸秆为底物不仅可以提供缓释碳源,而且可以作为吸附剂减弱重金属离子对SRB的抑制作用。