scholarly journals Evaluation of corrosion inhibition efficiency of some novel Schiff bases through a proposed QSAR model: DFT investigations supported by weight loss technique

2018 ◽  
Vol 34 (5) ◽  
pp. 2471-2476 ◽  
Author(s):  
Hamida Edan Salman ◽  
Asim A. Balakit ◽  
Ali Ahmed Abdulridha

A new aromatic Schiff base with azo linkage (AS) has been synthesized and characterized by FT-IR, 1H NMR and 13C NMR spectroscopic techniques. The new compound (AS) has been evaluated as carbon steel corrosion inhibitor at different concentrations (0.005, 0.01, 0.02, 0.04 and 0.08 mM) and different temperatures (303 – 333 K). The corrosion inhibition efficiency was studied by potentiodynamic polarization and weight loss measurements. The effects of concentration and temperature on the inhibition efficiency were studied by potentiodynamic polarization studies, the results showed that increasing concentration of AS increases the inhibition efficiency while increasing the temperature decreases it, the highest corrosion inhibition efficiency, 93.9% was recorded with 0.08 mM of AS at 313 K in 1 M H2SO4. Weight loss measurements showed that the inhibition efficiency reached 97.1% in the presence of AS (0.08 mM) at 313 K. The adsorption process was found to obey Langmuir isotherm, and the adsorption thermodynamic parameters were studied. Scanning electron microscope (SEM) was used to confirm the results.


2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Saeed Mohammadi ◽  
Fatemeh Baghaei Ravari ◽  
Athareh Dadgarinezhad

An investigation was conducted to improve the corrosion inhibition efficiency of molybdate-based inhibitors for mild steel which is the main construction material of cooling water systems, using nitroethane as an organic compound beside zinc. In this study a new molybdate-based inhibitor was introduced with the composition of 60 ppm molybdate, 20 ppm nitrite, 20 ppm nitroethane, and 10 ppm zinc. Inhibition efficiency of molybdate alone and with nitrite, nitroethane, and zinc on the uniform corrosion of mild steel in stimulated cooling water (SCW) was assessed by electrochemical techniques such as potentiodynamic polarization and electrochemical impedance (AC impedance) measurements. Weight loss measurements were made with coupon testing specimens in the room temperature for 48 h. Studies of electron microscopy, including scanning electron microscopy (SEM) photograph and X-ray energy dispersive spectrometry (EDS) microanalysis, were used. The results obtained from the polarization and AC impedance curves were in agreement with those from the corrosion weight loss results. The results indicate that the new inhibitor is as effective as molybdate alone, though at one-ninth of the concentration range of molybdate, which is economically favorable.


This paper presents the results of an experimental investigation carried out to study the effect of surface applied organic and inorganic corrosion inhibitors on reinforced steel in concrete. The reinforcement bars were coated with Neem powder (organic inhibitor) and Zinc powder (inorganic inhibitor) as corrosion inhibitors. The samples of beams of size 100X100X640mm having 4 steel bars as reinforcement were prepared and cured in normal water for 15 days and in saline environment for 42 days. The inhibitors were applied in the form of 2 coats, 4 coats and blend of both. The grade of concrete used was M30. Half-cell Potential and Weight loss measurements were carried out to determine the efficiency of corrosion inhibitors [11]. The corrosion inhibition efficiency of controlled specimen and coated specimens were compared. From the results it was seen that samples with 4 coats of Neem showed 44% inhibition efficiency as compared to control specimens. Similarly specimens with two coats of Neem, four coats of Neem and Zinc also showed better corrosion inhibition efficiency. Highest weight loss was observed in case of control specimen. The study concludes that use of surface applied corrosion inhibitors prove efficient in enhancing the corrosion inhibition efficiency of concrete. Surface applied corrosion inhibitors provide protective layer to the reinforcement thereby protecting it from corrosion and increasing the durability of the structure. This type of technique of using corrosion inhibitors in concrete can be used in various structures such as buildings, bridges, sewage pipes, marine structures, abutments & piers, RCC roads which are subjected to harsh environmental conditions.


Author(s):  
Yuli Yetri ◽  
E Emriadi ◽  
Novesar Jamarun ◽  
G Gunawarman

Efek inhibisi korosi dan sifat-sifat adsorpsi oleh ekstrak kulit buah kakao (Theobroma cacao)  pada baja lunak (mild steel) dalam larutan asam 1,5M HCl telah dipelajari menggunakan teknik konvensional metode berat hilang pada variasi waktu, konsentrasi dan suhu. Parameter-parameter termodinamika seperti energi aktivasi, entalpi, entropi dan perubahan energi bebas dihitung. Polarisasi elektrokimia telah dievaluasi untuk memastikan jenis inhibitor. Spektra infrared dan GCMS dilakukan untuk mengetahui senyawa ekstrak yang berperan  dalam proses inhibisi. Morfologi permukaan sampel diamati dengan menggunakan scanning electro microscopy dengan  energy dispersive X-ray spectroscopy (SEM-EDX) . Keseluruhan hasil penelitian menunjukkan bahwa ekstrak polar kulit buah coklat  dapat digunakan sebagai inhibitor korosi yang efektif pada baja karbon di lingkungan 1,5M HCl dengan pencapaian efisiensi  inhibisi   terkorosi sebesar 96.26% (weight loss) dan 92.08% (Tafel) pada konsentrasi ekstrak 2,5% selama768 jam. Mekanisme inhibisi adalah  adsorpsi chemiadsorpsi berdasar tingginya nilai entalpi dan energi bebas.Effisiensi Inhibisi diketahui meningkat dengan peningkatan konsentrasi dari ekstrak serta menurun dengan peningkatan suhu. Kurva polarisasi menunjukkan inhibitor ini berperilaku sebagai inhibitor campuran dengan dominan pada inhibisi katodik. Ekstrak diadsorpsi oleh permukaan mild steel  mengikuti model adsorpsi isotherm Langmuir. Kondisi permukaan mild steel menunjukan terjadinya adsorpsi di permukaan membentuk lapisan tipis di permukaan logam. Penambahan ekstrak kulit buah kakao ke dalam larutan HCl sangat efektif untuk mengurangi serangan korosi di permukaan mild steel.  Kata kunci: Korosi, Inhibitor, Theobroma cacao, Mild steel, Potensiodinamik Corrosion Inhibition Efficiency Mild Steel in Acid Media with Inhibitor Peels Extract of Cacao (Theobroma cacao)ABSTRACT Inhibition and adsorption properties of Theobroma cacao peel polar extract addition on corrosion inhibition efficiency of 0.3%C mild steel in hydrochloric acid solution for various exposuring time, extract concentration and working temperature were investigated using weight loss test method. Electrochemical polarization test was also conducted to confirm the effectiveness of inhibition. Infrared spectrum of the samples was also evaluated to reveal compounds of the extract which controll the inhibition process. Morphology and local composition of sample surfaces were respectively examined by scanning electron microscope  (SEM) and energy dispersive X-ray spectroscopy (EDX). Thermodynamic parameters such as energy activation, enthalpy, entropy and change in the free energy were then determined using related data. The results show that the inhibition efficiency increases significantly up to 96.3% (by weight loss method) and 92.08% (Tafel) with the increase of TCPE content. The optimum efficiency is obtained at extract concentration of 2,5% for exposuring time of 768h. However, the efficiency decreases slightly with increasing working temperature in the range of 303K-323K. The polarization curve shows the inhibitor behaves as a mixed inhibitor with the dominant cathodic inhibition. The adsorption model is found to obey Langmuir adsorption isotherm. Surface condition is  improved due to the adsorption and then formation of thin layer film protection in the surface of the steel. The addition of extract of cacao peels into HCl is effective to minimize corrosion attack on the mild steel. Key words: Corrosion, inhibitor, Theobroma cacao peel, Mild steel, Potensiodinamic


2008 ◽  
Vol 5 (2) ◽  
pp. 275-280 ◽  
Author(s):  
Atul Kumar

Effect of Sodium Lauryl Sulfate (SLS), a surfactant on corrosion of mild steel in 1 M hydrochloric acid was studied using three techniques namely: weight loss, electrochemical polarization and metallurgical research microscopy. Results obtained reveal that SLS is good inhibitor and shows very good corrosion inhibition efficiency (IE). The IE was found to vary with concentration of inhibitor and temperature. The electrochemical polarization result revealed that SLS is anodic in nature.


2020 ◽  
Vol 24 (4) ◽  
pp. 707-712
Author(s):  
N.C. Ngobiri ◽  
C. Obi

The corrosion inhibition capacity of Enantia chlorantha bark (ECB) extract on the corrosion of pipeline steel in an acidic environment was studied using the gravimetric method. The result revealed that weight loss obviously increased with the rise in temperature though trend lines were not parallel. The results obtained from the evaluation showed that the corrosion inhibition efficiency of the extract increased with extract concentrationattaining an efficiency of 89.02% with 2.5 g/L concentration at 30 ºC. The corrosion inhibition efficiency, however, decreased with increase in temperature, while the corrosion rate decreased. The significant achievement in this study was the ability of Enantia chlorantha extract to reduce the corrosion rate constant, increase its surface coverage with consequent longer material half-life in an acidic environment. Keywords: Inhibition efficiency, surface coverage, plant extract, weight loss, half-life


2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Maria Erna ◽  
Herdini Herdini ◽  
Abdullah Abdullah ◽  
Suharmin Suharmin

Abstrak Telah dipelajari efisiensi dan mekanisme inhibisi korosi karboksimetil kitosan (KMK) pada permukaan baja lunak dalam larutanH2SO4.Efisiensi inhibisi korosi ditentukan dengan menggunakan metode pengukuran berat hilang (Weight Loss Method), sedangkan mekanisme inhibisi korosi dipelajari berdasarkan hasil analisis karakterisasi Scanning Electron Microscope- Energy Dispersive X-ray(SEM-EDX). Hasil penelitian menunjukkan bahwa efisiensi inhibisi korosi KMK dalam H2SO4 mencapai 65.12%. Hasil analisis karakterisasi memperlihatkan mekanisme inhibisi KMK pada permukaan baja lunak melalui peristiwa adsorpsi kimia membentuk lapisan pasif berupa senyawa Fe-khelatmelalui unsur O dari gugus –OH dan N dari gugus –NH2 dari molekul KMK Kata kunci : Efisiensi inhibisi korosi, karboksimetil kitosan, mekanisme inhibisi   Abstract The corrosion inhibition efficiencyandmechanism ofcarboxymethylchitosan(CMC) on the surface ofmild steel in H2SO4 solution has studied. Determination of the corrosion inhibition efficiency measurement used Weight Loss Method (WLM), whereas the mechanism of corrosion inhibition studied based on the analysis characterizing Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX). The results showed that the corrosion inhibition efficiency of CMC reaches 65.12%. Characterization analysis results showed inhibition mechanism CMC on mild steel surface through chemical adsorption events form a passive layer of Fe-chelate compounds through O elementof -OH group and N element of -NH2 group of molecules KMK. Keywords : corrosion inhibittion efficiency, carboxymethyl chitosan, inhibition mechanism


2019 ◽  
Author(s):  
Chem Int

The corrosion inhibition characteristics of two medicinal molecules phenylalanine and rutin on mild steel in 1.0M Hydrochloric acid were evaluated using gravimetric method. Corrosion inhibition efficiency of 83.78 and 90.40 % was obtained respectively after seven days. However, phenylalanine showed weak accumulative higher corrosion inhibition efficiency. The presence of both molecules in the corrosive environment reduced the corrosion rate constant and increased the material half-life. Thermodynamic data calculated suggests a spontaneous adsorption of the molecules on the mild steel’s surface.


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