Evaluation of the Inhibitory Gel Aloe vera against Corrosion of Reinforcement Concrete in NaCl Medium

Most reinforced concrete structures in seaside locations suffer from corrosion damage to the reinforcement, limiting their durability and necessitating costly repairs. To improve their performance and durability, we have investigated in this paper Aloe vera extracts as a green corrosion inhibitor for reinforcing steel in NaCl environments. Using electrochemical methods (zero-intensity chronopotentiometry, Tafel lines and electrochemical impedance spectroscopy), this experimental work investigated the effect of these Aloe vera (AV) extracts on corrosion inhibition of concrete reinforcing bar (HA, diameter 12mm) immersed in a 0.5M NaCl solution. The results show that Aloe vera extracts have an average corrosion-inhibiting efficacy of around 86% at an optimum concentration of 20%.

Corrosion Inhibition of a Green Scale Inhibitor Polyepoxysuccinic Acid

The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be included in the category of corrosion inhibitors. It is not only a kind of green scale inhibitor, but also a green corrosion inhibitor. The synergistic effect between PESA and Zn2+ or sodium gluconate is poor. However, the synergistic effect among PESA, Zn2+ and sodium gluconate is excellent, and the corrosion inhibition efficiency for carbon steel is higher than 99%. Further study of corrosion inhibition mechanism reveals that corrosion inhibition of PESA is not affected by carboxyl group, but by the oxygen atom inserted. The existence of oxygen atom in PESA molecular structure makes it easy to form stable chelate with pentacyclic structure.

A Study of Eruca vesicaria, Bromelia hemisphaerica and Erythrina americana as Green Corrosion Inhibitors for Carbon Steel in Sulfuric Acid

A study of Eruca vesicaria, Bromelia hemisphaerica and Erythrina americana as eco-friendly corrosion inhibitors for 1018 carbon steel in 0.5 M H2SO4 has been carried out by using weight loss tests, potentiodynamic polarization curves and electrochemical impedance spectroscopy measuremnts. Results have shown that the three extracts performed as good corrosion inhibitors, but the Eruca vesicaria exhibited the best performance followed by Erythrina americana. The three inhibitors formed a protective, passive film which protected the steel from corrosion. This was because they contain antioxidants present in their molecular structure with heteroatoms such as N, C and O like phenols, amino acids, etc., which react with metal and environment to form the protective film.

Experimental and computational chemical studies on the cationic furanylnicotinamidines as novel corrosion inhibitors in aqueous solutions

The corrosion inhibition action of three newly synthesized furanylnicotinamidine derivatives namely: 6-[5-{4(dimethylamino)phenyl}furan-2-yl]nicotinamidine(MA-1256), 6-[5-(4-chlorophenyl)furan-2-yl]nicotinamidine(MA-1266), and 6-[5-{4-(dimethylamino)phenyl}furan-2-yl]nicotinonitrile(MA-1250) on carbon steel(C-steel) was investigated in 1.0 mol·L-1 HCl solution by weight loss(WL), potentiodynamic polarization(PP), electrochemical impedance spectroscopy(EIS), and electrochemical frequency modulation(EFM)techniques. Morphological analysis was performed on the uninhibited and inhibited C-steel using atomic force microscope(AFM) and Infrared Spectroscopy(ATR-IR) methods. The effect of temperature was studied and discussed. Inspection of experimental results revealed that the inhibition efficiency(IE) increases with the incremental addition of inhibitors and with elevating the temperature of the acid media. The adsorption of furanylnicotinamidine derivatives on C-steel follows Temkin’s isotherm. PP studies indicated that the investigated compounds act as mixed-type inhibitors and showed that p-dimethylaminophenyl furanylnicotinamidine derivative(MA-1256) was the most efficient inhibitor among the other studied derivatives with IE reached(95%)at 21 × 10-6 mol·L-1. MA-1266 is highly soluble in aqueous solution and has non-toxicity profile with LC50 N 37 mg·L-1. Thus, MA-1266 can be a promising green corrosion inhibitor candidate with IE N 91% at 21× 10-6 mol·L-1. The experiments were coupled with computational chemical theories such as quantum chemical and molecular dynamic methods. The experimental results were in good agreement with the computational outputs.

<i>Juniperus communis</i>Extract Effect on Bronze Corrosion in Natural 0.5 M Chloride Medium

The effect of Juniperus communis (JC) extract on the inhibition of bronze corrosion in aqueous chloride solution was studied by electrochemical polarization methods. The variation of two experimental factors such as the chloride concentration and the temperature allows us to deduce the kinetics parameters of this process (Ea = 65.7 kJ&bull;mol–1). Thermodynamic calculations indicated that JC adsorption on bronze surface obeyed Arrhenius adsorption isotherm and was characterized by an endothermic process (ΔH* = 54.7 kJ&bull;mol–1).

Corrosion Inhibition of Carbon Steel in Acidic Mediaby Using Actinidia deliciosa(Kiwifruit)Extract

The corrosion inhibition of 1018 carbon steel in 0.5 M H2SO4 by using Actinidia deliciosa (Kiwifruit) peel extract has been investigated by using potentiodynamic polarization curves and electro-chemical impedance spectroscopy. Two kinds of extracts are investigated, one from the tender, and another one from ripe Actinidia deliciosa. Concentrations include 0, 25, 50, 75, and 100 ppm at room temperature. Results indicate that both kind of extracts acted as good corrosion inhibitors, is more efficient in the ripe extract. Corrosion inhibition efficiency increases with increasing its concentration for ripe extract, whereas for the tender Actinidia deliciosa, the higest inhibitor efficiency is obtained by adding 25 ppm and decresaing with a further increase in its concentration. Both extracts improve the passive film properties by decreasing the passive current density values. It is found that the corrosion inhibition is due to the presence of heteroatoms present in Actinidia deliciosa, mainly quercitine, which is physically adsorbed in the steel following a Frumkin type of adsorption isotherm which forms a protective film.

绿色高效缓蚀剂研究现状

缓蚀剂具有微量高效的特点,能够防止金属腐蚀,同时保持金属的物理性能和力学性能不变,且使用方便,因而被广泛地应用。传统金属缓蚀剂的生物降解性差,有毒性,且易对环境造成污染。基于环境保护、可持续发展和绿色化学的理念,传统金属缓蚀剂的使用受到了严格的限制,缓蚀剂的研究逐渐转向环境友好型物质。将绿色环保类缓蚀剂分为单一体系类缓蚀剂和复配体系类缓蚀剂,并对其近年来的研究进展进行了全面综述,分类归纳了各类缓蚀剂的优势和劣势,对绿色缓蚀剂的现状及研究方向进行了展望。

基于分子动力学模拟的绿色缓蚀剂研发分析

绿色缓蚀剂的研发是大势所趋。采用分子动力学模拟方法,对植物有效活性成分的缓蚀潜力进行分析,深入研究缓蚀剂分子在金属表面的吸附过程。共模拟了21种有效活性成分的腐蚀抑制过程,计算得到缓蚀剂分子在金属表面的吸附能,并以此作为缓蚀剂作用效果的判断依据。结果表明,刺天茄果实、柚皮、墨旱莲、竹叶、橘皮和橄榄叶等具有良好的缓蚀潜力,植物分子倾向以平行的方式吸附于铁表面,阻碍金属与腐蚀溶液的接触,起到减缓或抑制腐蚀的作用。经电化学实验验证,分子动力学模拟结果可信。分析得到的缓蚀潜力较大的6种植物提取物对20号钢均有一定的缓蚀效果,其中电化学实验测得竹叶的缓蚀效率最高,为93.06%。从微观入手进行植物原料筛选,有效规避了常规实验筛选的偶然性与盲目性,可有效分析其缓蚀机理,提高实验效率,减轻实验负担。

环境友好型缓蚀剂的研究进展

本文综述了金属缓蚀剂的研究进展。近年来,随着科学技术的不断发展,金属材料的需求与日俱增,金属材料因机械强度高、耐久性好而在许多有前景的领域中都是不可或缺的。但是金属材料易腐蚀,缓蚀剂的存在可以阻滞或减缓金属的腐蚀进程。人们对可持续发展认识的不断提高,环境友好型缓蚀剂必将成为今后的发展趋势。环境友好型缓蚀剂可分为无机缓蚀剂、有机缓蚀剂,本文着重介绍了一些常用的环境友好型缓蚀剂,并对其发展前景进行了展望。

绿色气相缓蚀剂的研究进展

近年来,随着人们对健康、环保和安全等方面意识的不断提升以及相关法律法规的落实,工业上对金属制品生产和应用过程中起防护作用的气相缓蚀剂提出了更高要求,一些毒性高、对环境有影响的气相缓蚀剂受到了使用限制。因此,研发和推广新一代环保、安全的气相缓蚀剂势在必行。此外,可再生资源的开发利用是人类社会可持续发展的重要措施。源自自然界动植物的可再生资源,特别是农作物、瓜果蔬菜和林木加工废弃物等资源中含有大量天然抗氧剂、防腐剂、抑菌剂等成分,作为气相缓蚀剂开发利用的潜力很大,目前国内外研究人员已经对这类新一代绿色气相缓蚀剂开展了重点研究。概述了气相缓蚀剂的发展历程,总结了氨基酸、聚天冬氨酸、植物源化合物、植物提取物等绿色气相缓蚀剂的研究现状,并对绿色气相缓蚀剂的发展趋势进行了展望,以为其产业化应用提供必要的支持。

水溶性植物提取物缓蚀剂的研究进展

在一些恶劣的环境下,如潮湿环境、酸性或碱性环境、大气腐蚀环境等,设备会因环境问题而发生不同程度的腐蚀。因此,关于设备的腐蚀防护就尤为重要。加入缓蚀剂就是一个很好的防腐蚀的办法。近年来,对于缓蚀剂的研究已经成为研究热点,除了关注缓蚀剂,还有效率等基本问题,由于如今社会对生态意识提高的重视,无毒无害易获得的缓蚀剂也成为研究的关键。绿色缓蚀剂的应用成为现代社会防腐的重要途径之一,它可以使腐蚀速度降低,提高设备的使用寿命并且价格低廉容易获得。本文对植物型水溶性缓蚀剂进行介绍。

绿茶提取物作为酸洗缓蚀剂的性能研究

在众多金属防腐方法中,缓蚀剂具有用量少、效果明显、方便经济等优点,备受研究人员的关注,而近年来,植物提取物由于其来源广泛,绿色环保等优势更是研究热点。使用超声提取法从绿茶中提取活性物质作金属酸洗缓蚀剂,采用了失重法探究了其在1mol·L^(-1)HCl溶液中对碳钢片的缓蚀作用,并通过单因素实验和正交实验(L9(3~3))探究不同温度、不同时间和不同绿茶提取物浓度下对碳钢片的缓蚀效率,为后续工作提供一定的数据支撑。通过实验发现,在实验温度为30℃,作用时间为10h,缓蚀剂用量为0.16mg·mL^(-1)时,具有良好的缓蚀效率,可以达到88.60%。最后通过红外表征初步探讨了其缓蚀机理。

绿色环保型缓蚀剂的研究现状

缓蚀剂为石油、石化、电力等行业减轻或避免金属腐蚀带来的损失发挥了重要作用。随着环保意识的不断增强和社会可持续发展的要求,缓蚀剂在研发、生产、使用过程中也逐步向绿色、低碳转型,在追求更高的缓蚀效率的同时,对其安全性和环保性也提出了更高的要求。本研究结合国内外缓蚀剂的研究与应用情况,从天然原料的提取、低毒的同系物或衍生物合成、副产品的利用以及碳基纳米等新型材料的开发等方面,对绿色环保型缓蚀剂的研究开发途径进行了总结。

Exopolysaccharide produced by Vibrio neocaledonicus sp. as a green corrosion inhibitor:Production and structural characterization

An exopolysaccharide substances produced by Vibrio neocaledonicus sp. was introduced as a novel green inhibitor against the corrosion of carbon steel in artificial seawater and acidic media. The produced extracellular polymeric substance（EPS） is heterogeneous with composition of polysaccharides, nucleic acids and protein and average molecular weight of 29,572 Da. Adsorption of EPS on the metal surfaces and formation of Fe-EPS complexes acted as a barrier to prevent the oxygen penetration and hindered anodic and cathodic reactions. The inhibitory effect increases with increasing EPS concentration and exposure time. The highest corrosion inhibitory effect（95.1%） was observed for 10 g/L of EPS after 5 days of exposure in seawater. This is the highest inhibitory effect ever been reported by EPSs. While, the optimum concentration of EPS with the highest inhibition efficiency in 1 N H;SO;was 1000 ppm. The influence of different parameters, such as initial pH, growth phase, various nitrogen and carbon sources on the production of EPS and its corrosion inhibitory effect were also investigated. According to results,the optimum culture medium for EPS production is contained artificial seawater including 5% mannitol as carbon source and 0.1%（NH;）;SO;as nitrogen source at pH = 8. This medium could produce 22.24 g/L EPS during 3 days’ incubation at 30 ℃. The corrosion inhibitory efficiency of obtained EPS was 95.97%.

绿色杀菌缓蚀剂对不同粗糙度碳钢的腐蚀行为影响研究

目的揭示绿色杀菌缓蚀剂对不同粗糙度碳钢表面SRB+IOB生物膜的杀菌缓蚀行为与规律的影响。方法本文采用失重实验、表面分析、电化学测试等手段,探究20#碳钢在不同粗糙度(240#、600#、1200#)下,添加绿色杀菌缓蚀剂对混合菌的杀菌行为和对碳钢的缓蚀效果的影响,阐明D-酪氨酸分解抑制生物膜的作用机理。结果试样表面的腐蚀产物层厚度、点蚀坑大小与深度随表面粗糙度的降低、杀菌缓蚀剂的添加,而减小。在不添加杀菌缓蚀剂情况下,碳钢随表面粗糙度从240#降到1200#,其年腐蚀深度由0.186 mm/a降到了0.157 mm/a,下降幅度达15.6%。自腐蚀电流密度icorr由20.5 mA/cm^(2)降到了6.93 mA/cm^(2),下降幅度高达66.2%。其中,在240#表面粗糙度下,碳钢年腐蚀深度由不添加杀菌缓蚀剂的0.186 mm/a降到了添加杀菌缓蚀剂的0.116 mm/a,下降幅度达37.6%。icorr由20.5 mA/cm^(2)降到了11.8 mA/cm^(2),下降幅度达42.4%。结论随表面粗糙度降低,碳钢表面趋于光滑,应力集中减小,碳钢表面很难聚集混合菌里的硫化物、矿化物,以及腐蚀性阴离子,H+很难与阴离子结合形成酸性环境,不易产生氧浓差电池,减缓了均匀腐蚀向局部腐蚀的转变,降低了点蚀发生概率。而D-酪氨酸的加入可将生物膜中的细菌由固着态转变为浮游态,同时破坏了细菌细胞结构、蛋白质、氧浓差环境,进而增强了杀菌缓蚀效果。

环保型缓蚀剂在化工机械设备腐蚀防护中的应用

研究了一种基于丁香籽水提取物的环保型绿色缓蚀剂,分析了其在1 mol·L^(-1)HCl溶液中对低碳钢表面的缓蚀作用。通过电化学以及表面形态学实验,考察了丁香籽水提取物的缓蚀性。使用交流阻抗法和极化法探测了该缓蚀剂电化学特性。通过扫描电子显微镜(SEM)和接触角测试,表征了未接触缓蚀剂和接触缓蚀剂金属试样的表面形貌。交流阻抗分析揭示了使用800 mg·L^(-1)丁香籽提取物,在金属浸泡2.5 h后,具有显著的缓蚀度(93%),归因于缓蚀剂在低碳钢表面的吸附。根据极化试验结果,腐蚀抑制发生在阴阳极反应。SEM结果表明,800 mg·L^(-1)丁香籽提取物引入腐蚀介质可以有效保持钢表面的光滑。通过拟合Langmuir吸附等温线,验证了单层吸附模型。因此,丁香籽提取物分子与钢表面反应,在钢表面覆盖一层单分子层,从而达到良好的缓蚀效果。

绿色气相缓蚀剂的复配及其缓蚀性能研究

目的 为解决单组分绿色气相缓蚀剂缓蚀性能差的问题,复配一种绿色复合气相缓蚀剂,探究其对碳钢和黄铜金属试样的缓蚀作用。方法 采用腐蚀质量损失、接触角、电化学等试验测试分析复合气相缓蚀剂对碳钢、黄铜的缓蚀效果与成膜耐久性。结果 复合气相缓蚀剂对10号钢、H62黄铜的缓蚀效率分别为84.71%、91.67%,缓蚀性能显著优于单组分气相缓蚀剂;复合气相缓蚀剂在10号钢、H62黄铜表面均形成了缓蚀膜,H62黄铜表面形成的缓蚀膜较10号钢的更具耐久性。结论 与单组分气相缓蚀剂相比,该复合气相缓蚀剂对碳钢、黄铜均具备良好的缓蚀作用,为绿色气相缓蚀剂的防锈包装应用提供支撑。

绿色缓蚀剂氨基酸在抑制金属腐蚀方面的应用

传统缓蚀剂,因其不可生物降解,从而导致环境问题。氨基酸类缓蚀剂是目前颇具前景的环境友好型绿色缓蚀剂。氨基酸是蛋白质的基本构成物质,由于它具有小分子结构,从而稳定性非常好,并且可广泛应用于酸性介质、中性介质及大气腐蚀介质中。综述了氨基酸类绿色缓蚀剂的缓蚀原理、来源及提取方法、缓蚀检测方法及其在缓蚀方面的应用,并对氨基酸类缓蚀剂的应用及发展前景进行了展望。

绿色水处理剂的研究与应用

介绍绿色水处理剂的概念及发展现状,对绿色水处理剂进行了详细的分类介绍,并指出了目前我国绿色水处理剂存在的问题,并提出了相应的建议.文章指出,多功能绿色水处理剂是未来水处理剂主要的发展方向.

天然植物绿色缓蚀剂的研究进展

综述了缓蚀剂的反应机理、分类以及测试方法,阐述了从天然植物中提取绿色缓蚀剂的发展历程,提出了天然友好缓蚀剂的研制要求,展望了其发展趋势:应继续以天然植物、海产植物以及植物废弃物为主要原料,提取、分离、加工高效的新型环境友好缓蚀剂,以此实现资源的优化利用.