缓蚀剂吸附行为的电化学及AFM力曲线研究

结合极化曲线,微分电容曲线测试和AFM力曲线技术研究了直链十二胺对氯化钠溶液中铜镍合金的缓蚀行为以及吸附机理。结果表明:十二胺在合金表面形成单分子层吸附膜而起到缓蚀作用。十二胺浓度越大,吸附膜越致密,缓蚀率越高,力曲线上测得的粘附力值也越大。质子化的十二胺在荷负电的合金表面的吸附使电极零电荷电位正移,电荷屏蔽作用使得AFM力曲线上探针与试样之间的长程静电斥力减小。     

非水体系苯并咪唑及衍生物吸附的电化学表面增强拉曼光谱研究

应用电化学现场表面增强拉曼光谱(SERS)以及直接电化学合成技术分别研究了非水体系中苯并咪唑及2-巯基苯并咪唑在铜电极表面的吸附行为及其与三苯基膦(pph3)共存的表面过程.在较负电位区间苯并咪唑主要以分子形式吸附在电极表面.在较正电位区间,电极表面生成类高分子(CuBIM)n膜,具有缓蚀作用,对含有pph3的该体系,Cu+首先与pph3配位形成稳定的阳离子,进入溶液之后与BIM配位生成稳定的配合物,导致不能在表面有效地成膜而破坏了苯并咪唑的缓蚀作用.2-巯基苯并咪唑在Cu表面主要通过自组装单层方式在电极表面吸附,且在实验测试的电位区间内,MBI均是以S端与金属表面作用,其吸附取向随电位正移由倾斜逐渐向接近垂直过渡,并在金属表面形成MBI单分子层膜.pph3的加入不影响MBI在Cu电极表面的成膜行为.电化学现场模拟合成及产物结构组成解析为推断表面反应过程提供了直接证据.     

吡咯烷二硫代氨基甲酸铵自组装膜对铜的缓蚀作用

吡咯烷二硫代氨基甲酸铵(APDTC)是一种环境友好型金属缓蚀剂, 以其在铜表面制备了自组装单分子膜(SAMs), 用电化学方法研究在0.5 mol·L-1 HCl介质中APDTC SAMs对铜的缓蚀作用及其吸附行为. 结果表明, APDTC分子易在铜表面形成稳定的APDTC SAMs, 改变了电极表面的双电层结构, SAMs同时抑制了铜的阳极氧化过程和阴极还原过程, 铜电极的电荷转移电阻明显提高, 双电层电容明显降低. 电化学阻抗和极化曲线测试结果显示, 在0.5 mol·L-1 HCl介质中, 铜表面APDTC SAMs表现出良好的缓蚀效果. 研究结果还表明, APDTC的吸附行为符合Langmuir吸附等温式, 吸附机理是介于化学吸附和物理吸附之间的一种吸附.     

3-氨基-1,2,4-三氮唑自组装膜对黄铜的缓蚀作用

3-氨基-1,2,4-三氮唑(ATA)是一种环境友好型金属处理剂, 以其在黄铜表面制备了自组装单分子膜(SAMs), 用电化学方法研究ATA SAMs对黄铜的缓蚀作用及其吸附行为. 结果表明, ATA分子易在黄铜表面形成稳定的ATA SAMs, SAMs抑制了黄铜的阳极氧化过程, 改变了电极表面的双电层结构, 固/液界面双电层电容明显降低, 有良好的缓蚀效果. 研究结果还表明, ATA的吸附行为符合Langmuir吸附等温式, 吸附机理是典型的化学吸附.     

再生水环境中304不锈钢生物膜腐蚀电化学特征

研究了以再生水作为循环冷却系统补水的北京某热电厂冷却塔底粘泥中分离纯化培养出来的硫酸盐还原菌(SRB)生长特性.采用原子力显微镜(AFM)、扫描电镜(SEM)、能谱分析仪(EDS)和电化学交流阻抗(EIS)方法研究了304不锈钢(SS304)表面生物膜特征及其主要成分和不锈钢/生物膜界面电化学行为.结果显示,再生水环境下304不锈钢表面形成的生物膜是由吸附的SRB菌体及以含碳有机物为主的胞外聚合物和FeS腐蚀产物构成.浸泡前期(前7 d)SS304电极表面阻抗值主要由SS304表面钝化膜的贡献;浸泡后期(14 d后),电极体系阻抗值由不锈钢表面钝化膜和生物膜共同贡献.     

铜表面缓饰的喇曼光谱电化学研究

近年来，随着国民经济的发展，金属缓蚀研究越来越受到人们的重视，在金属缓蚀机理研究中最常用的手段就是电化学方法和现场光谱技术，特别是表面增强喇曼散射光谱技术（SERS）；由于它极大的增强效应，可以用其研究金属表面微量物质的吸附行为．它不需要其它现场光谱技术所必需的高真空、高温等技术，即可得到吸附在金属表面物质的结构信息．本文对两种缓蚀剂［‘］，2一氨基苯并咪吐和6一硝基苯并咪娃在铜表面的吸附行为进行了喇曼光谱电化学研究，通过改变铜电极电位对两种缓蚀剂的各主要喇曼振动谱带进行了观察，对它们在银表面的吸附…     

碱基腺嘌呤与胸腺嘧啶在Au(111)电极上的共吸附

用循环伏安法(CV)和电化学扫描隧道显微镜(ECSTM)在HClO4溶液中研究了配对碱基腺嘌呤(Adenine,A)与胸腺嘧啶(Thymine,T)在Au(111)电极上的共吸附行为.CV曲线表明,A和T的电化学共吸附行为更接近于A的电化学吸附行为.高分辨STM图像显示,在物理吸附区域碱基A和T分子之间通过氢键作用形成一种不同于单组分的网络结构.根据STM图像提出一个可能的模型,并给出了在Au(111)电极上共吸附时A和T分子之间可能的氢键作用方式.     

蛋白质在导电聚甲基丙烯酰吡咯上的吸附

采用表面引发原子转移自由基聚合(SIATRP)技术在硅片及金膜表面上制备导电聚丙烯酰吡咯(PMAP),并对聚合物薄膜的化学结构等进行了表征.采用表面等离子谐振生化分析仪(SPR)原位考察了牛血清白蛋白(BSA)在聚合物表面上的吸附行为,通过改变缓冲液的pH值和BSA的浓度对蛋白质吸附的影响,探讨了BSA在PMAP上的吸附机理.采用电化学循环伏安测试考察了蛋白质吸附对于导电聚合物的电化学行为的影响.采用原子力显微镜(AFM)考察了BSA在聚合物表面上吸附前后聚合物的表面形貌变化.     

DTAB-KTL复合添加剂抑制锌电极腐蚀的协同效应

应用失重法、电化学方法、扫描电镜等研究十二烷基三甲基溴化铵(DTAB)、咳特灵(KTL)复合添加剂抑制锌在KOH(3mol/L)溶液的缓蚀作用.结果表明:与单一添加剂相比,DTAB-KTL复合添加剂缓蚀效果更好.由于二者的协同效应,使KTL更容易吸附在锌电极DTAB表面,提高缓蚀作用.     

丹皮酚的电化学氧化及其反应机理研究

研究了在碱性磷酸盐缓冲溶液体系中,丹皮酚在固体电极上的电化学吸附氧化行为。与苯酚的电化学性质比较表明,碱性溶液中丹皮酚在电极表面上发生类似的不可逆的氧化。氧化产物发生随后化学反应,在电极表面生成致密的不导电聚合物膜。利用超微电极技术研究了丹皮酚电化学氧化的动力学过程,并用时间分辨快速扫描现场红外光谱电化学证明了电极表面的聚合物膜是芳醚类聚合物。     

Utilization of biowaste as an eco-friendly biodegradable corrosion inhibitor for mild steel in 1 mol/L HCl solution

This report focuses on the application of a biodegradable biowaste [human hair-(HHR)], to produce a mild steel corrosion inhibitor. The performance of HHR extract in inhibiting metallic corrosion in 1 mol/L HCl was investigated. The analysis of the metal corrosion behavior using electrochemical and weight loss techniques revealed that HHR exhibits an efficient corrosion-mitigating effect via adsorption on the metal surface following a Langmuir isotherm. Tafel-plot results revealed the mixed-mode corrosion protection behavior of HHR. Surface analysis using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and Fourier transform infrared (FT-IR) spectroscopy provided evidence for the precipitation of a protective HHR film on the metal surface.     

Adsorption and inhibition properties of Tephrosia Purpurea as corrosion inhibitor for mild steel in sulphuric acid solution

Abstract

The present study investigated the adsorption and inhibition behavior of leaf extract of Tephrosia Purpurea (T. purpurea) on mild steel corrosion in 1?N H₂SO₄ solution using electrochemical and surface morphological methods. Techniques adopted for electrochemical studies were Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) technique; and surface morphological studies were carried out using Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The leaf extract of T. purpurea was characterized using UV-Visible spectroscopy (UV-Vis), Fourier-Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance Spectroscopy (NMR) and Gas Chromatography – Mass Spectrometry (GCMS). The results obtained from electrochemical studies exhibited the potential of T. purpurea as good corrosion inhibitor. And, it was found that, the inhibition efficiency (I.E in %) increases with increase in concentration of the inhibitor molecules, the optimum inhibitor concentration observed was 300?ppm and the inhibition efficiency of 93% was observed at this inhibitor concentration. Above 300?ppm, there was not much changes in inhibition efficiency. Polarization studies provided the information that the inhibition is of mixed type and EIS confirmed that the corrosion process is controlled by single charge transfer mechanism. And, it was obtained that, the adsorption of inhibitor molecules obeys Langmuir adsorption isotherm. The inhibition is mainly by the adsorption of inhibitor molecules on the mild steel electrode surface, which was confirmed by FT-IR, SEM and AFM studies. Through all the experimental results, it can be arrived that, the leaf extract of T. purpurea performed as a good corrosion inhibitor for mild steel in 1?N sulfuric acid medium.     

红四氮唑在盐酸介质中对冷轧钢的缓蚀作用

用失重法、电化学法和原子力显微镜（AFM）研究了红四氮唑在1.0 mol/L ~ 5.0 mol/L HCl介质中对冷轧钢的缓蚀作用。结果表明：红四氮唑对冷轧钢具有良好的缓蚀作用,为混合抑制型缓蚀剂,且在钢表面的吸附符合Langmuir吸附模型;并通过吸附热力学和动力学参数详细讨论了缓蚀作用机理;AFM测试结果表明红四氮唑在钢表面吸附形成了致密的缓蚀剂膜层。     

抑制Q235钢CO2腐蚀的气液双相咪唑啉衍生物缓蚀剂的缓蚀行为

采用失重法、交流阻抗(EIS)及傅里叶变换红外光谱(FT-IR)、原子力显微镜(AFM)、X射线光电子能谱(XPS)等表面分析测试方法首次研究了硫脲基咪唑啉衍生物(TAI)作为抑制CO₂腐蚀的气液双相缓蚀剂的缓蚀行为. 结果表明, 该硫脲基咪唑啉缓蚀剂能有效地抑制Q235 钢在气液双相中的CO₂腐蚀. AFM测试结果表明该缓蚀剂能显著地降低碳钢表面的腐蚀破坏, 并且由于碳钢表面形成的缓蚀剂吸附膜的疏水作用,可在AFM探头和碳钢表面之间检测到更大的粘附力, 而探针与试样表面之间的长程静电斥力在气相中增加,在液相中由于表面电荷的屏蔽效应而减小. XPS和FT-IR 光谱测试表明液相中和气相中在碳钢表面形成吸附膜的缓蚀剂成分分别是硫脲基咪唑啉衍生物和其酸水解产物——酰胺. 以上结果也进一步证实了咪唑啉衍生物在酸性溶液中的水解机理.     

AFM and FTIR studies of organic cation adsorption on carbon steel coupled with stainless steel

The electrochemical behavior of the anode of the galvanic couple and the adsorption behavior of the cationic inhibitor on it have been investigated by using electrochemical methods, atomic force microscopy (AFM) and infrared spectroscopy (FTIR) technology. A galvanic electrode was prepared by coupling N80 carbon steel (CS) and S31803 stainless steel. All experiments were performed in NaCl solution in the presence or absence of an inhibitor. The results show that, in aqueous NaCl solution, CS carries negative excess charge, for the couple, positive charge is carried on the CS side (anode). The adsorption behavior of the cationic inhibitor on CS is significantly affected by the excess charge carried on it. Owing to the charge interaction between electrodes and the cationic inhibitor, the inhibitor has a greater tendency to adsorb on the single CS and less tendency to adsorb on the CS of the couple. Because of this, the adsorption film on the anode (CS side) of the couple is thin and defective. The failure of inhibiting galvanic corrosion attributes to the defective protective layer formed on the anodic area. Copyright © 2006 John Wiley & Sons, Ltd.     

电化学原子力显微镜的应用

评述了电化学原子力显微镜的原理和技术及其在现场电化学和电分析化学领域的应用,如观察电镀、腐蚀和防腐的过程,电化学沉积膜的形成和特点,测定两表面间的静电力等,指出其存在的一些缺陷,并对经过改造后的电化学原子力显微镜进行了综述。     

咪唑啉酰胺在电偶电极表面的吸附行为

采用原子力显微镜技术研究了有机阳离子缓蚀剂(咪唑啉酰胺)在电偶电极表面的吸附行为, 并探讨了其腐蚀抑制机理. 结果表明, 金属表面的过剩电荷较大地影响缓蚀剂分子的吸附行为. 在1%的NaCl溶液中, 碳钢电极表面带有过剩的负电荷；不锈钢电极表面带有过剩的正电荷；碳钢电极和不锈钢电极耦合后, 其表面分别带有过剩的正电荷和负电荷. 在耦合前阳离子缓蚀剂分子仅吸附在碳钢表面, 耦合后缓蚀剂分子在偶对的阴极(不锈钢)和阳极(碳钢)表面均有吸附, 但缓蚀剂分子在碳钢表面的吸附强度和覆盖度较之耦合前降低, 缓蚀剂的腐蚀抑制能力减弱.     

Corrosion Inhibition of Mild Steel by Safflower (Carthamus tinctorius) Extract: Polarization,EIS, AFM,SEM, EDS,and Artificial Neural Network Modeling

Inhibitory action of safflower (Carthamus tinctorius) extract (SE) was investigated in hydrochloric acid solution through electrochemical (polarization, EIS), and surface analysis (optical microscopy/atomic force microscopy (AFM)/scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS)) techniques. In addition, Inhibition efficiency was predicted by neural network (NN) modeling in elevated temperatures and different acid concentrations. The thermodynamic adsorption parameters propose that this inhibitor retard both cathodic and anodic processes through physical adsorption and blocking the active corrosion sites. Surface analysis techniques confirm the inhibitor adsorption on the metal surface, which is in accordance with the variation of apparent activation energy of corrosion. Finally, inhibition efficiency is discussed in terms of protective film formation.     

Nanotechnological evaluation of protein adsorption on dialysis membrane surface hydrophilized with polyvinylpyrrolidone

Hydrophilizing synthetic polymer dialysis membranes with polyvinylpyrrolidone (PVP) play an important role for inhibition of protein adsorption on membrane surface. In the present study, the effect of PVP on protein adsorption was evaluated from a nano-scale perspective. Swelling behavior of PVP present on wet polysulfone (PS)/PVP film surfaces was observed by atomic force microscopy (AFM). Fibrinogen and human serum albumin (HSA) were immobilized on the tip of AFM probes, with which a force-curve between protein and wet PS/PVP film surface was measured by AFM while scanning in order to visualize two-dimensional protein adsorbability on film surfaces. Furthermore, HSA adsorbability on non-PVP containing PEPA dialysis membrane (FLX-15GW) and PVP containing PEPA dialysis membrane (FDX-150GW) was evaluated by the AFM force-curve method. As a result, PS/PVP film surface was completely covered with hydrated and swollen PVP at 5 wt% or more PVP content. Protein adsorbability on PS/PVP film surfaces decreased greatly with increasing content of PVP. The adsorption of HSA was inhibited by the presence of PVP on film surfaces more significantly than that of more hydrophobic fibrinogen. HSA adsorbability on wet FLX-15GW dialysis membrane surface was 428 ± 174 pN whereas that on wet FDX-150GW dialysis membrane surface was 42 ± 29 pN.