Corrosion inhibition and adsorption behavior of <Emphasis Type="Italic">Murraya koenigii</Emphasis> extract for corrosion control of aluminum in hydrochloric acid medium

The corrosion behavior of aluminum in the hydrochloric acid medium of pH 3 was studied using Tafel polarization and electrochemical impedance spectroscopy techniques in the presence or the absence of the Murraya koenigii (commonly known as curry) leaves extract at 303 K to 323 K. The concentration of the inhibitor used was in a range of 0.05–0.4 gL^?1. The inhibition efficiency was found to increase with increasing the inhibitor concentration and decreasing temperature. Polarization data showed that the curry leaves extract (CLE) acted as anodic type of inhibitor at lower concentrations of the inhibitor and as mixed type at higher concentrations of the inhibitor. The maximal inhibition efficiency of 91.79% was obtained with the CLE at its optimum concentration of 0.4 gL^?1. Adsorption of the CLE was found to obey the Langmuir adsorption isotherm and underwent both physisorption and chemisorption process. The kinetic and thermodynamic parameters were calculated and discussed in detail. The results obtained by both methods were in good agreement with each other. The protective film formed on the surface of aluminum by the adsorption of inhibitor molecules present in the CLE in the hydrochloric acid medium of pH 3 was confirmed by the scanning electron microscopy and energy-dispersive X-ray spectroscopy. So, the CLE emerged as a potential, cost-effective and eco-friendly natural inhibitor for the corrosion control of aluminum in the hydrochloric acid medium.     

硫酸介质中桂花果提取液对Q235钢的缓蚀作用

目的研究在0.5 mol/L硫酸溶液介质中,桂花果提取液(OFFE)对Q235钢的缓蚀作用及机理。方法通过失重法和极化曲线、电化学阻抗谱等电化学方法研究了桂花果提取液对Q235钢在0.5 mol/L硫酸溶液介质中的缓蚀性能,考察了25℃下桂花果提取液浓度对缓蚀效率的影响,并对缓蚀机理进行了探讨。结果以95%的乙醇为溶剂浸提制备的桂花果提取液在0.5 mol/L硫酸介质中对Q235钢具有良好的缓蚀性能,缓蚀效率随其质量浓度的增加而增大,当其浓度达到10 g/L时,其缓蚀效率可达91.48%。电化学测试结果表明,桂花果提取液为混合型缓蚀剂,主要通过抑制阴极析氢过程来减缓Q235钢的腐蚀,缓蚀机理为"几何覆盖效应",其有效缓蚀成分在Q235钢表面的吸附符合Langmuir等温式,吸附平衡常数为1.09 L/g。结论在0.5 mol/L的硫酸介质中,桂花果提取液对Q235钢具有明显的缓蚀作用,是一种有广泛应用前景的天然绿色缓蚀剂。     

Corrosion inhibition of mild steel in 1 M HCl solution by henna extract: A comparative study of the inhibition by henna and its constituents (Lawsone, Gallic acid, α-d-Glucose and Tannic acid)

The inhibitive action of henna extract (Lawsonia inermis) and its main constituents (lawsone, gallic acid, α-d-Glucose and tannic acid) on corrosion of mild steel in 1 M HCl solution was investigated through electrochemical techniques and surface analysis (SEM/EDS). Polarization measurements indicate that all the examined compounds act as a mixed inhibitor and inhibition efficiency increases with inhibitor concentration. Maximum inhibition efficiency (92.06%) is obtained at 1.2 g/l henna extract. Inhibition efficiency increases in the order: lawsone > henna extract > gallic acid > α-d-Glucose > tannic acid. Also, inhibition mechanism and thermodynamic parameters are discussed.     

Adsorption and inhibitive properties of Phoenix dactylifera L. Extract as a green inhibitor for aluminum and aluminum-silicon alloy in HCl

The inhibition efficiency of alcoholic extract of Phoenix dactylifera plant on aluminum and aluminumsilicon in 0.5 M hydrochloric acid solution have been evaluated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM). Values of inhibition efficiency obtained are dependent upon the plant extract concentration and temperature. Generally, inhibition was found to increase with increasing the inhibitor concentration, but decreased with increasing the temperature. The effect of temperature on the corrosion behavior of Al and Al-Si alloy in 0.5M HCl with and without addition of plant extract was studied in the temperature range 20–60°C. Thermodynamic functions of dissolution processes were calculated from experimental EFM data and the interpretation of the results are given. Physical adsorption mechanism has been proposed for the inhibition and Temkin adsorption isotherm was obeyed for Al and Al-Si alloy.     

几种植物叶提取物在HCl中对锌的缓蚀作用

采用失重法首次研究了钓鱼慈竹(Neosinocalamus affinis)竹叶提取物(NALE),三角枫(Acer buergerianum)叶提取物(ABLE)和滇润楠(Machilus yunnanensis)叶提取物(MYLE)在盐酸中对锌的缓蚀作用。详细考察了缓蚀剂浓度(0.1~1.0g/L)、温度(30~60℃)、腐蚀浸泡时间(6~72 h)和盐酸浓度(0.01~0.05 mol/L)对缓蚀性能的影响。结果表明:三种植物提取物在0.01 mol/L HCl溶液中均对锌具有良好的缓蚀作用,且在锌表面的吸附符合Langmuir吸附等温式。缓蚀率随缓蚀剂浓度的增加而增大,但随温度、盐酸浓度和腐蚀浸泡时间的增加而减小。三种植物提取物的缓蚀率排序为:NALEABLEMYLE。     

Corrosion Inhibition of Mild Steel in Sulphuric Acid Using Luffa Aegyptiaca Leaves Extract

The corrosion inhibition of mild steel（MS） in sulphuric acid using Luffa aegyptiaca（LA） leaves extract was investigated by weight loss studies, colorimetric measurements, potentiodynamic polarisation and electrochemical impedance spectroscopy. The adsorption of LA leaves extract was confirmed by Fourier transform infrared spectroscopy and optical profilometry. The inhibition efficiency increased with increasing concentration of the extract but decreased with rise in temperature and with the increase in acid strength. Furthermore, the inhibition efficiency synergistically increased on the addition of halide ions. Polarisation studies revealed that the LA extract acts as mixed- type inhibitor. Physical adsorption mechanism is proposed from the trend in inhibition efficiency with the change in temperature and from thermodynamic parameters. The adsorption of LA on MS surface obeys Langmuir adsorption isotherm and follows the kinetic thermodynamic model of ElAwady at all temperatures studied.     

Inhibition of 304 stainless steel corrosion in acidic solution by Ferula gumosa (galbanum) extract

The inhibition effect of the extract of galbanum (Ferula gummosa Boiss.) on the corrosion of 304 stainless steel in 2 M HCl solution was studied by weight loss measurements, Tafel polarization, and electrochemical impedance spectroscopy (EIS) methods. It was found that the inhibition efficiency (IE) increases as the extract concentration is increased. Tafel polarization method revealed the mixed mode inhibition of galbanum extract (GE) with predominant control of anodic reaction. The effect of temperature on the corrosion behavior of steel indicates that inhibition efficiency of the natural substance increases with the rise in temperature. At all temperatures, the adsorption of the extract components onto the steel surface was found to follow the Temkin adsorption isotherm.     

Application of Anise Extract for Corrosion Inhibition of Carbon Steel in CO<Subscript>2</Subscript> Saturated 3.0% NaCl Solution

The corrosion inhibition of carbon steel in CO₂-saturated 3% NaCl solution by anise extract (AE) dissolved in ethylene glycol (EG) was studied using weight loss, electrochemical and surface analysis (AFM) techniques. Inhibition efficiency increased with increase in AE concentration and temperature, reaching maximum value of 93% at 400 ppm AE concentration. Polarization results show that AE functions as a mixed-type inhibitor. Corrosion inhibition is assumed to occur by physicochemical adsorption following Langmuir adsorption isotherm model. Morphological studies of the carbon steel electrode surface undertaken by AFM confirm the adsorption of the extract on the metal surface.     

Electrochemical behavior of aluminium in acidic media

The inhibitive action of the acid extracts of seeds' leaves and bark from the Ficus virens plant towards hydrochloric and sulfuric acid corrosion of aluminium is tested using mass loss and thermometric techniques. It was found that the extract acts as a good corrosion inhibitor for aluminium corrosion in all concentration of hydrochloric and sulfuric acid solution. The ellagic acid has been used as a representative of the tannin species. The tannins are anodic inhibitors. The inhibition efficiency (IE) increases as the extract concentration is increased. The effect of temperature on the IE was studied. It was found that the presence of extract increases the activation energy of the corrosion reaction. Moreover, the heat of adsorption (Q_ads) was also calculated. It was found that the Ficus virens extract provides a good protection against pitting corrosion in chloride ion containing solution.     

Gossipium hirsutum L. extracts as green corrosion inhibitor for aluminum in NaOH solution

The corrosion inhibition properties of Gossypium hirsutum L. leave extracts (GLE) and seed extracts (GSE) in 2 M sodium hydroxide (NaOH) solutions were studied using chemical technique. Gossypium extracts inhibited the corrosion of aluminium in NaOH solution. The inhibition efficiency increased with increasing concentration of the extracts. The leave extract (GLE) was found to be more effective than the seed extract (GSE). The GLE gave 97% inhibition efficiency while the GSE gave 94% at the highest concentration.     

尿酸自组装膜对镍缓蚀行为的影响

采用极化曲线和交流阻抗技术研究了尿酸自组装膜对Ni在3%NaCl溶液中的缓蚀行为。结果表明,尿酸属于阳极型缓蚀剂,随着尿酸浓度的变化、组装时间和尿酸溶液pH值的不同,缓蚀效率有所不同。当尿酸浓度为0.8 mmol/L、溶液pH=9.0、组装 时间为12 h时电极的腐蚀电流密度最小,缓蚀效率最高,达到95.7%。     

Corrosion inhibition of mild steel by plant extract in dilute HCl medium

The inhibition effect of Zenthoxylum alatum plant extract on the corrosion of mild steel in 5% and 15% aqueous hydrochloric acid solution has been investigated by weight loss and electrochemical impedance spectroscopy (EIS). The corrosion inhibition efficiency increases on increasing plant extract concentration till 2400 ppm. The effect of temperature on the corrosion behaviour of mild steel in 5% and 15% HCl with addition of plant extract was studied in the temperature range 50-80 °C. Surface analysis (SEM, XPS and FT-IR) was also carried out to establish the corrosion inhibitive property of this plant extract in HCl solution. Plant extract is able to reduce the corrosion of steel more effectively in 5% HCl than in 15% HCl. The adsorption of this plant extract on the mild steel surface obeys the Langmuir adsorption isotherm.     

十六烷基二甲基乙基溴化铵在硫酸介质中对Q235钢的缓蚀性能研究

采用静态失重法,动电位极化曲线法和电化学阻抗法研究了十六烷基二甲基乙基溴化铵 (CDAB) 在硫酸介质中对Q235钢的缓蚀行为,并探讨了其对Q235钢的缓蚀作用机理.结果表明,在25 ℃下,缓蚀率随CDAB浓度增大而增大,在浓度仅为10 mgL^-1时,失重缓蚀率达85%左右.极化曲线实验结果显示,CDAB是一种以控制阳极反应为主的混合型缓蚀剂,且静态失重法,动电位极化曲线法和电化学阻抗法实验结果相一致.CDAB在Q235钢表面的吸附服从Kastening-Holleck吸附等温模型;CDAB的添加显著增大了腐蚀反应的活化能,有效抑制了腐蚀反应的进行.     

Inhibition of aluminum corrosion using Opuntia extract

The inhibitive action of the mucilage extracted from the modified stems of prickly pears, toward acid corrosion of aluminum, is tested using weight loss, thermometry, hydrogen evolution and polarization techniques. It was found that the extract acts as a good corrosion inhibitor for aluminum corrosion in 2.0 M HCl solution. The inhibition action of the extract was discussed in view of Langmuir adsorption isotherm. It was found that the adsorption of the extract on aluminum surface is a spontaneous process. The inhibition efficiency (IE) increases as the extract concentration is increased. The effect of temperature on the IE was studied. It was found that the presence of extract increases the activation energy of the corrosion reaction. Moreover, the thermodynamic parameters of the adsorption process were calculated. It was found also that the Opuntia extract provides a good protection to aluminum against pitting corrosion in chloride ion containing solutions.     

The role of acid anion on the inhibition of the acidic corrosion of steel by lupine extract

The inhibitive effect of lupine (Lupinous albus L.) extract on the corrosion of steel in aqueous solution of 1 M sulphuric and 2 M hydrochloric acids was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Potentiodynamic polarization curves indicated that the lupine extract acts as a mixed-type inhibitor. EIS measurements showed that the dissolution process is under activation control. The inhibition efficiency of the extract obtained from impedance and polarization measurements was in a good agreement and was found to increase with increasing concentration of the extract. The obtained results showed that, the lupine extract could serve as an effective inhibitor for the corrosion of steel in acid media and the extract was more effective in case of hydrochloric acid. Theoretical fitting of the corrosion data to the kinetic-thermodynamic model was tested to show the nature of adsorption.     

硫酸介质中榕树叶提取液的缓蚀性能及其与 KI 的缓蚀协同效应

通过电化学方法和失重法,研究了榕树叶提取液(FLE)对碳钢在硫酸溶液中的缓蚀性能,同时研究了它与KI的缓蚀协同效应,探讨了缓蚀机理。研究结果表明:在硫酸溶液中,FLE对碳钢属混合抑制型缓蚀剂,缓蚀效率随其浓度的增加而增大;FLE与KI之间存在良好的协同效应,两者复配后,体系的腐蚀电流密度减小,电荷传递电阻增大,双电层电容减小,缓蚀效率增大,表现出更好的缓蚀作用;FLE与KI复配前后,其在碳钢表面的吸附均为自发过程,且符合Langmuir吸附等温方程。     

电化学法研究芭蕉叶提取物在盐酸中对碳钢的缓蚀作用

目的研究芭蕉叶提取物(MBLE)在酸性环境中对碳钢腐蚀的抑制行为。方法通过热水浸提法获取MBLE,采用电化学方法研究在不同实验温度和不同浓度下MBLE在1 mol/L盐酸溶液中对碳钢的缓蚀行为,并用扫描电镜(SEM)研究金属表面腐蚀形貌。结果极化曲线研究表明,MBLE对碳钢在1mol/L盐酸中的腐蚀有明显抑制作用,属阴极抑制为主的混合型缓蚀剂;其缓蚀性能随质量浓度增大而增强,25℃时160 mg/L的MBLE缓蚀效率达到94.7%。电化学阻抗图谱研究表明,随着MBLE质量浓度的增大,碳钢表面腐蚀反应的电荷转移电阻逐渐增大,腐蚀反应抑制程度增强。变温试验研究表明,MBLE在实验温度范围内具有较好的稳定性。当MBLE质量浓度为160 mg/L时,温度从25℃增加到40℃,两种电化学方法所得缓蚀效率的变化幅度均在3%以内。MBLE缓蚀剂分子在碳钢表面的吸附服从Dhar-Flory-Huggins等温吸附式,并且属于物理和化学混合吸附。SEM研究表明,盐酸介质中MBLE可有效地抑制碳钢的腐蚀。结论对碳钢在盐酸介质中的腐蚀,MBLE是有效的绿色缓蚀剂。     

Corrosion inhibition of mild steel in hydrochloric acid by 6‐aminohexanoic acid

The inhibiting behavior of 6‐aminohexanoic acid (C₆H₁₃NO₂) on mild steel corrosion in 1 M HCl as corroding solution at 25 °C was evaluated by weight loss, polarization, and electrochemical impedance spectroscopy (EIS) methods. The weight loss, polarization, and EIS measurements were relatively in good agreement together. Results obtained by the three methods showed that the inhibition efficiency (%IE) increases with increasing the concentration of 6‐aminohexanoic acid up to 6.86 × 10^?05 M (about %IE = 80). It was also found that the adsorptive behavior of the investigated inhibitor on the steel surface followed Langmuir‐type isotherm, the 6‐aminohexanoic acid acted as a mixed type inhibitor and its inhibition mechanism obeys from the chemisorption interaction between 6‐aminohexanoic acid and the mild steel.     

Synergistic effects of formaldehyde and alcoholic extract of plant leaves for protection of N80 steel in 15%HCl

Abstract

The synergistic effects of formaldehyde and an alcoholic extract of plant leaves have been studied by weight loss measurements at temperatures up to 363 K using various concentration ratios of the two inhibitors to protect N80 steel against corrosion in 15% hydrochloric acid. The inhibition efficiency was found to decrease with increasing temperature for all except two of the various concentration ratios that were studied. After identifying these two most promising mixtures, their corrosion prevention effects for N80 steel in hydrochloric acid were studied in more detail by weight loss and potentiostatic polarisation measurements. The corrosion rate of the steel was decreased by the presence of small additions of the inhibitors. The extent of decrease was found to depend on the nature of the corrosion inhibitor and its concentration. The inhibition efficiencies of the two plant based inhibitor mixtures were compared with those of two commercially available oil industry corrosion inhibitors. In all cases the adsorption of the inhibitors on the steel appeared to follow the Frumkin or Langmuir adsorption isotherm. The inhibition efficiencies of the two plant based inhibitors and the two commercial inhibitors were evaluated at a concentration level of 0.8% for temperatures in the range 303 K to 363 K) and exposure times of between 1 h and 24 h. Thermodynamic parameters including the free energy of adsorption, activation energy, enthalpy and entropy were calculated in both the absence and presence of inhibitors. Potentiostatic polarisation tests have revealed that inhibitors are primarily of the anodic type.     

HCl溶液中氨基酸复合缓蚀剂对碳钢的缓蚀作用

采用失重法和电化学方法,研究了半胱氨酸、蛋氨酸对盐酸介质中碳钢的缓蚀作用.失重实验结果表明:半胱氨酸、蛋氨酸的用量为800 mg/L时,对碳钢的缓蚀率仅分别为66.61％和62.44％.与蛋氨酸相比,半胱氨酸与环烷基咪唑啉季铵盐有较好的协同作用,组分质量比为1∶1,总用量为1 600 mg/L,缓蚀率达到91.050％...