L-蛋氨酸对预腐蚀Q235碳钢缓蚀性能的分子动力学研究

采用失重法、密度泛函理论和分子动力学模拟研究了预腐蚀对L-蛋氨酸在60℃、1M的HCl溶液中对Q235碳钢的影响和缓蚀剂的缓蚀机理。结果表明:预腐蚀作用降低了L-蛋氨酸对Q235碳钢缓蚀作用,缓蚀率下降15%。密度泛函理论和分子动力学模拟结果表明,羧基上的氧原子带有明显的负电荷能够吸附到金属表面形成缓蚀剂膜,发挥缓蚀作用,为成膜缓蚀机理。L-蛋氨酸在没有预腐蚀的Q235碳钢表面吸附分子数为24时,缓蚀剂膜最致密。而L-蛋氨酸在预腐蚀后的Q235碳钢表面吸附时的吸附能显著降低,缓蚀剂在碳钢表面的分布密度也明显下降,这很好解释了预腐蚀作用降低了缓蚀剂缓蚀率的实验结果。本文的研究结果对缓蚀剂的研究和实际应用具有一定的指导意义。     

盐酸介质中水杨醛缩氨基硫脲对碳钢的缓蚀作用

合成了新型席夫碱缓蚀剂:水杨醛缩氨基硫脲(ST),并考察了其在1 mol/L盐酸溶液中对碳钢的缓蚀性能。通过静态失重、动电位极化曲线、交流阻抗等技术手段研究缓蚀剂浓度对腐蚀速率及缓蚀效率的影响,阐明缓蚀作用机理。结果表明,ST在盐酸介质中对碳钢具有良好的缓蚀性能。随着缓蚀剂浓度的增加,缓蚀效率逐渐增大。ST的加入显著降低了自腐蚀电流密度,为抑制阴极反应为主的缓蚀剂。ST在碳钢表面的吸附符合Langmuir吸附模型,为物理吸附与化学吸附共同作用。     

咪唑啉衍生物在H_2S水溶液中的腐蚀抑制机理(英文)

使用失重法和电化学极化技术研究了咪唑啉衍生物在H2S水溶液中对碳钢腐蚀的抑制机理.结果表明:咪唑啉衍生物能有效抑制H2S的腐蚀,属于阴极型缓蚀剂.咪唑啉衍生物在金属表面上的吸附符合Langmuir等温吸附,温度越高,越有利于吸附.加入缓蚀剂后,降低了腐蚀反应的活化能和指前因子,而指前因子是腐蚀反应的决定因素,因此缓蚀剂的加入能降低腐蚀速率.     

2-十一烷基-N-羧甲基-N-羟乙基咪唑啉在柠檬酸溶液中对碳钢的缓蚀作用

采用失重实验、极化曲线和交流阻抗等方法研究了缓蚀剂2-十一烷基-N-羧甲基-N-羟乙基咪唑啉在质量分数为2%柠檬酸溶液中对碳钢的缓蚀性能。 失重实验表明,该缓蚀剂在柠檬酸溶液中能够有效地抑制碳钢的腐蚀,当其质量分数为0.4%时,缓蚀效率达到86.4%。 极化曲线表明,该缓蚀剂为混合型缓蚀剂,Nyquist图中单一的容抗弧变化表明碳钢电极表面的腐蚀过程主要由电荷转移步骤控制。 该缓蚀剂的吸附行为符合Langmuir吸附等温式,吸附机理是介于物理吸附和化学吸附之间的一种吸附。     

绿色聚天冬氨酸复配缓蚀剂对A3碳钢的缓蚀抑雾作用

采用失重法和极化曲线法研究了聚天冬氨酸(PASP)和十二烷基酚聚氧乙烯醚(OP-10)复配对A3碳钢在6mol·L-1HCl腐蚀介质中的协同吸附行为及缓蚀抑雾作用.结果表明:复配缓蚀剂可有效抑制A3碳钢在HC1介质中的腐蚀,当PASP浓度为20g·L-1,缓蚀率可达94%,抑雾率83%;随着温度的升高,复配缓蚀剂的缓蚀性能下降.复合缓蚀剂在钢表面的吸附符合校正的Langmuir模型,吸附过程为放热、熵减的自发过程;复配体系属于阳极型缓蚀剂.     

1-(2-羟乙基)-2-烷基-咪唑啉缓蚀剂缓蚀机理的理论研究

采用量子化学计算、分子动力学模拟和分子力学相结合的方法, 对6种不同烷基链长的1-(2-羟乙基)-2-烷基-咪唑啉缓蚀剂抑制H2S腐蚀的缓蚀机理进行研究, 并对其缓蚀性能进行评价. 前线轨道分布和Fukui指数表明, 6种缓蚀剂分子的反应活性区域均集中在分子的咪唑环上, 3个反应活性中心分别位于咪唑环上的N(4), N(7)和C(8)原子, 可使咪唑环在金属表面形成多中心吸附. 分子的反应活性及活性区域分布对烷基链长并不敏感. 单分子吸附能、膜的内聚能、吸附角和链间距的计算数据显示, 缓蚀剂膜的稳定性以及膜与金属基体的结合强度随链长的增加而增大; 当正构烷基碳链长度大于13时, 缓蚀剂可在金属表面形成一层高覆盖度、致密的疏水膜, 能有效阻碍溶液中的腐蚀介质向金属表面扩散, 从而达到阻碍或延缓腐蚀的目的.     

多点位吸附型咪唑啉季铵盐缓蚀剂的合成及其缓蚀性能

以对二甲氨基苯甲酸、二乙烯三胺和氯化苄为原料,两步法合成了一种新型具有多个潜在吸附中心的季铵盐型咪唑啉缓蚀剂（MIQ）,利用傅里叶变换红外光谱对合成的产物进行了表征。 通过失重法研究了该缓蚀剂在6%盐酸溶液中对碳钢的缓蚀性能。 讨论了缓蚀剂用量、温度、时间对缓蚀性能的影响,并研究了其与某些物质复配后的协同作用。 结果表明,合成的季铵盐型咪唑啉缓蚀剂在6%的盐酸腐蚀环境中,用量为0.5%时对碳钢的缓蚀率可达97%以上,缓蚀率随温度的升高和时间的延长而降低。 MIQ与乌洛托品、KSCN以及KI等复配后可以显著改善缓蚀剂的缓蚀率。 从吸附等温线推测,该缓蚀剂抑制腐蚀的机理是缓蚀剂在碳钢表面吸附成膜,进而有效阻挡了碳钢表面与酸性清洗试剂的接触。     

红茶提取液在盐酸中对碳钢的缓蚀作用

采用动电位极化曲线和交流阻抗（EIS）研究了红茶提取液（BLE）在盐酸介质中对碳钢的缓蚀性能和缓蚀机理。 研究结果表明,采用索氏提取法从红茶茶叶中提取的缓蚀剂,对碳钢在1.0 mol/L盐酸溶液中具有良好的缓蚀性能,随着提取物浓度的增加,缓蚀效率增大。 红茶提取液中的有效缓蚀成分为抑制阴阳极反应的混合型缓蚀剂,在碳钢表面的吸附符合Langmuir等温式,属于单分子层吸附。     

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.     

阳离子型可聚合咪唑类离子液体-丙烯酰胺共聚物的制备及其对盐酸腐蚀碳钢缓蚀行为

利用阳离子型可聚合离子液体1-丙烯酰氧乙基-3-甲基咪唑四氟硼酸盐与丙烯酰胺的反相微乳液共聚合,制备了阳离子型咪唑类离子液体-丙烯酰胺共聚物缓蚀剂,并探讨了其缓蚀性能。研究了不同阳离子度、不同浓度聚合物溶液的缓蚀性能以及吸附时间对盐酸腐蚀碳钢速率的影响,并初步讨论了缓蚀机理。研究表明,该种阳离子型缓蚀剂的缓蚀效率可达90%以上;缓蚀剂的缓蚀能力不仅取决于缓蚀剂的阳离子度,还取决于该种缓蚀剂的相对分子质量;缓蚀效率并非简单地随聚合物浓度的增加而提高,当聚合物溶液的浓度过高时,反而会使缓蚀效率下降;随吸附时间的延长,碳钢的腐蚀速率逐渐降低,约40 h后基本保持不变;加入缓蚀剂有效抑制了酸对铁的腐蚀,随缓蚀效率的提高,碳钢表面的粗糙程度明显降低,孔洞结构减少。     

Effect of pH Value on the Adsorption Behavior and Inhibition Mechanism of Dodecylamine on Carbon Steel

The effect of pH value on the adsorption behavior and inhibition mechanism of dodecylamine for carbon dioxide corrosion of carbon steel was investigated by electrochemical methods and scanning electron microscopy (SEM). The results indicated that the pH value of the solution played the crucial role to the adsorption behavior and inhibition mechanism of dodecylamine. The inhibition performance of dodecylamine on carbon steel was dependent on the pH value and the inhibition efficiency increased with the increase of pH value. At pH 4.9, dodecylamine mainly inhibited the cathode process of the corrosion. The adsorption energy of dodecylamine on the metal surface was lower. The adsorption of dodecylamine on the metal surface was not stable and an anode desorption phenomenon could be observed. Hence, dodecylamine did not provide effective inhibition to the corrosion. While at pH 6.9, it had much higher adsorption energy. Dodecylamine adsorbed on the metal surface tightly and formed the effective diffusion barrier which inhibited both the cathode and anode processes effectively.     

硫酸溶液中聚天冬氨酸对碳钢的吸附缓蚀性能

应用电化学极化曲线和交流阻抗研究聚天冬氨酸(PASP)对碳钢的缓蚀性能,讨论了PASP浓度和温度对缓蚀效果的影响.结果表明:PASP是一种以抑制阳极为主的缓蚀剂.在实验温度范围内,PASP在0.5mol/L硫酸溶液中对碳钢的缓蚀效率随着温度升高而降低,并以10℃时的缓蚀效果最好.在给定温度下,缓蚀率均随PASP浓度的增加而迅速增加,但当PASP质量浓度达到2.5g/L时,缓蚀率的增加趋于平缓,10℃下,缓蚀率的最高值可达80.33%(PASP 6.0g/L),PASP在碳钢表面的吸附基本服从Freund lich吸附等温式,PASP的加入增大了碳钢的腐蚀反应表观活化能.     

Study on the corrosion inhibition of biomass carbon quantum dot self- aggregation on Q235 steel in hydrochloric acid

At present, the development of efficient green corrosion inhibitors has become one of the important directions of metal corrosion protection. In this paper, biomass carbon quantum dots (BCQDs) were prepared by hydrothermal reaction using biomass precursors. The optical properties and structural composition of the synthesized BCQDs were characterized in detail. After that, the corrosion inhibition performance of BCQDs was evaluated by EIS, Tafel, SEM and TEM. The electrochemistry and surface tests demonstrate that the aggregates can effectively prevent Q235 steel from corrosion in 1 M HCl medium at 298 K-328 K, with the maximum inhibition efficiency of 94.1 % at the concentration of 200 mg/L at 308 K. Finally, the corrosion inhibition mechanism was analyzed by FTIR, CA and XPS on the surface of the corroded carbon steel samples. The inhibition mechanism suggests that BCQDs can inhibit metal corrosion by self-aggregation and adsorption on metal surface. This is owing to its small size effect and functional groups containing heteroatoms, easily forming dense protective film.     

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。     

玉米醇溶蛋白/十二烷基硫酸钠复合物对碳钢的缓蚀效应

通过失重法、扫描电镜和极化曲线法研究了玉米醇溶蛋白/十二烷基硫酸钠(zein/SDS)复合物对碳钢的缓蚀效应。在1mol/L盐酸溶液中,加入0.05‰zein对碳钢的缓蚀率为65.5%,而加入zein/SDS复合物(0.05‰zein+0～8mmol/L SDS)能够使碳钢的缓蚀率逐渐增高至90.1%。随着zein/SDS复合物中SDS浓度的增大,碳钢表面逐渐由深坑面腐蚀变为局部点腐蚀,最终趋于平整。极化曲线测试表明,zein/SDS复合物能够有效抑制碳钢表面电极反应的发生。纯zein与碳钢表面吸附的ΔG_(ads)值表明,zein在碳钢表面主要发生静电吸附作用,而zein/SDS复合物对碳钢的缓蚀效应主要来源于zein同碳钢表面之间的配位吸附作用,这是由于SDS类胶束之间的静电斥力引起zein空间构象的改变。     

Inhibition of cold rolled steel corrosion by Tween-20 in sulfuric acid: weight loss, electrochemical and AFM approaches

The inhibiting action of a nonionic surfactant of Tween-20 on the corrosion of cold rolled steel (CRS) in 0.5-7.0 M sulfuric acid (H(2)SO(4)) was studied by weight loss and potentiodynamic polarization methods. Atomic force microscope (AFM) provided the surface conditions. The results show that inhibition efficiency increases with the inhibitor concentration, while it decreases with the sulfuric acid concentration. The adsorption of inhibitor on the cold rolled steel surface obeys the Langmuir adsorption isotherm equation. Effect of immersion time was studied and discussed. The effect of temperature on the corrosion behavior of cold rolled steel was also studied at four temperatures ranging from 30 to 60 degrees C, the thermodynamic parameters such as adsorption heat, adsorption free energy, and adsorption entropy were calculated. The results revealed that the adsorption was physisorption mechanism. A kinetic study of cold rolled steel in uninhibited and inhibited acid was also discussed. The kinetic parameters such as apparent activation energy, pre-exponential factor, rate constant, and reaction constant were calculated for the reactions of corrosion. The inhibition effect is satisfactorily explained by both thermodynamic and kinetic models. Polarization curves show that Tween-20 is a cathodic-type inhibitor in sulfuric acid. The results obtained from weight loss and potentiodynamic polarization are in good agreement, and the Tween-20 inhibition action could also be evidenced by surface AFM images.     

Cucumber (Cucumis sativus L.) Leaf Extract as a Green Corrosion Inhibitor for Carbon Steel in Acidic Solution: Electrochemical,Functional and Molecular Analysis

An extract of cucumber leaves (ECSL) was prepared as a green corrosion inhibitor for carbon steel. Its carbon steel corrosion inhibition performance against 0.5 mol L⁻¹ H₂SO₄ was investigated using electrochemical methods and scanning electron microscopy (SEM). Its composition was analyzed by gas chromatography and mass spectroscopy (GC−MS). Quantum chemical calculations and molecular dynamics simulations (MDS) were conducted to elucidate the adsorption mechanism of the inhibitor molecules on the carbon steel surface. The results indicated that the inhibition efficiency increases with its increasing concentration. The extract acted as a mixed type corrosion inhibitor, and its inhibition properties were ascribed to the geometric coverage effect induced by its adsorption on the metal surface in accordance with Langmuir’s law. The active components in the extract were identified as mainly organic compounds with functional groups such as aromatic moieties and heteroatoms. The inhibition activities of ECSL are delivered through the ability of the active components to adsorb on the metal surface through their functional groups to form a protective layer which hinders the contact of aggressive substances with carbon steel and thus suppresses its corrosion. This research provides an important reference for the design of green corrosion inhibitors based on plant waste materials.     

MDOPD在Q235钢表面的吸附特性研究

应用静态失重法、动电位扫描极化曲线、交流阻抗和原子力显微镜等方法研究含咪唑杂环的双季铵盐化合物MDOPD在模拟油田水中对Q235钢的缓蚀性能及其缓蚀吸附机理.结果表明,双季铵盐化合物MDOPD在模拟油田水介质中对Q235钢具有非常显著的缓蚀效果;其缓蚀吸附膜随吸附时间的延长而更加完整和致密;MDOPD的较强缓蚀性能与其分子中含有多个活性吸附中心以及在金属表面的平卧吸附方式有关.