Electrochemistry Characteristic of Carbon Steel under Biofilm and Sulfide Film

应用丝束电极技术比较了SRB生物膜以及硫化物膜对Q2 35碳钢腐蚀过程的影响机制 ,采用电位、电流扫描技术测试了生物膜和FeS膜下的碳钢腐蚀不均匀性特征 ,发现由于膜的导电性致使表面电位扫描已不能作为膜下局部腐蚀的判据 .动电位扫描表明无氧近中性溶液中 ,硫化物膜对碳钢具有一定保护作用 .电化学阻抗谱显示 ,硫化物膜电容增加缓慢 ,其极化电阻Rp 随时间呈先增后降的趋势 .与硫化物膜相比 ,生物膜表现出极大的电容 (10 4 ～ 10 5μF/cm2 ) ,且膜电容随时间呈S型增加 ,而极化电阻Rp 则呈指数下降 ,由此可知生物膜加速了腐蚀Wire Beam Electrode (WBE) made of Q235 carbon steel was applied to study the heterogeneous corrosion beneath biofilm formed by Sulfate Reducing Bacteria (SRB) in culture and sulfide film in solution with 1% NaCl and 300 mg/L S 2- . The potential,galvanic density mapping,as well as polarization curve and Electrochemical Impedance Spectrum (EIS) were measured to predict the localized corrosion under biofilm and sulfide film.As a result,the mapping showed the potential fluctuation on the WBE surface decreased over time due to the conductivity of the biofilm and sulfide film.Therefore,the potential mapping could not be a criterion of localized corrosion under biofilm.Instead,the current mapping could give a good prediction to the MIC.The sulfide film could inhibit corrosion of carbon steel.However,the biofilm accelerate the corrosion.Polarization resistance R p increased over time in the Na 2S solution if lack of O 2.In addition,the biofilm capacity moved up to a very large level (～10 5 μF/cm 2)in shape of Sigmoid with its polarization resistance decreasing exponentially when SRB grew.作者联系地址：华中科技大学化学系!湖北武汉430074,华中科技大学化学系!湖北武汉430074,华中科技大学化学系!湖北武汉430074,华中科技大学化学系!湖北武汉430074Author's Address: Dept. of Chem.,Huazhong Univ. of Science and Technology,Wuhan 430074,Chin

Corrosive Electrochemical Behavior of Carbon Steel in Microbiological Medium

硫酸盐还原菌 (SRB)生长代谢 ,溶液pH值从 7.5下降到 5.8,并在碳钢表面形成生物膜 ,改变了生物膜下碳钢表面的微环境 ,促进碳钢点蚀的形成 .清除表面的腐蚀产物后 ,碳钢基体表面为分布不均匀的溃斑 ,发生严重的点蚀行为 .而SRB的活性和生物膜的结构诱发碳钢腐蚀的形成和生长 ,在微生物快速生长过程中出现明显的氢扩散电流峰 ,加剧碳钢的渗氢行为 ,采用电化学阻抗 (EIS)研究了碳钢在微生物腐蚀过程中生物膜的结构与腐蚀相应的变化关系Sulfate_reducing bacteria(SRB)grows and propagates, PH of the solution is dropped from 7.5 to 5.8,and forms the biofilms on carbon steel in culture medium.The micro_environment on the surface of carbon steel is changed under the biofilms,the factors accelerate the formation of the pitting corrosion. When the biofilm on carbon steel is cleaned out,the surface of carbon steel have the non_uniform pitting corrosion. The activity of SRB and the porous structure of biofilms induced the initiation and development of the pitting corrosion of carbon steel.The process of microbiologically induced corrosion(MIC) involves the development of SRB activity,which promotes the permeation of gydrogen into the carbon steel.The relation of the structure of biofilms and corrosion was also studied using electrochemical impedance spectroscopy(EIS).作者联系地址：清华大学核能技术设计研究院,华中科技大学化学系,华中科技大学化学系,华中科技大学化学系,华中科技大学化学系,清华大学核能技术设计研究院 北京100084 ,湖北武汉30074 ,湖北武汉30074 ,湖北武汉30074 ,湖北武汉30074 ,北京100084Author's Address: 1.Institute of Nuclear Energy TechnologyINET,Tsinghua University,Beijing 100084,China; 2.Chem.Dept.,Huazhong University of Science and Technology,Wuhan 4300

一种含氧化合物转化制烯烃微球催化剂及其制备方法

本发明一种含氧化合物转化制烯烃微球催化剂及其制备方法。该催化剂体系由氧化硅、氧化磷及氧化铝构成，亦可同时含有碱土金属氧化物及过渡金属氧化物。各组分质量含量为氧化硅2～60％，氧化磷8-50％，氧化铝20-70％，碱土金属氧化物0-10％，过渡金属氧化物0-20％，且满足各组分质量含量之和为100％。其特征在于采用特定的磷酸硅铝分子筛或含过渡金属的磷酸硅铝分子筛(如SAPO-34)作为催化剂活性组分，与其它含各氧化物组分的原料及作为造孔剂的有机化合物(如天然产物田菁粉)混合，制成具有一定固含量的浆料，经充分胶磨后，喷雾干燥并高温焙烧，制成具有适宜粒度分布、磨损指数和较高催化性能的微球催化剂。带填