mixed type inhibitor
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2021 ◽  
Author(s):  
Ameena M. Al-bonayan ◽  
Ahmed El-Hossiany ◽  
Dalia M. Eid ◽  
Abd El-Aziz S. Fouda

Abstract The proton pump inhibitor lansoprazole (PPIL) drug is examined as corrosion inhibitor for high carbon steel (HCS) dipped in 1.0M HCl. The study was conducted utilizing ac impedance spectroscopy (EIS), Mass loss (Ml), polarization tests, and surface checks were utilized to illustrate the importance of this PPIL extract to the prevent corrosion process for HCS. The influence of temperature and concentration of PPIL on the efficiency of inhibition were tested. The corrosion mechanism occurs, when the PPIL extract molecules block the active center in the electrode surface. The inhibition efficiency (%IF) of HCS occurs by the adsorption procedure and HCS is subject to the adsorption of Langmuir. Polarization curves showed that PPIL drug is a mixed- type inhibitor that retards the dissolution of HCS. IF % was deliberated with altering in the concentration of PPIL various temperature of the medium. From the outcome data we get that the good agreement in the all methods.


Author(s):  
Junjie Chen ◽  
Yaya Zhang ◽  
Dequan Zeng ◽  
Bingchang Zhang ◽  
Xiaohong Ye ◽  
...  

2021 ◽  
Author(s):  
Ahmed F. Molouk ◽  
Mohamed F. Atia ◽  
Abd El-Aziz S. Fouda

Abstract Aizoon extract used as anti-corrosion for stainless steel430 (SS430) in 2M hydrochloric acid solution. The mass reduction, electrochemical impedance, and potentiodynamic polarization were carried out to demonstrate the performance of Aizoon extract as corrosion resistance for SS430. Polarization revealed that the Aizoon extract is mixed type inhibitor with superiority to inhibiting the cathodic reaction. The inhibition percentage reaches 93% at 300 ppm extract. Adsorption of the extract on SS430 surface is regular with Langmuir adsorption model. Thermodynamic factors for adsorption and activation processes for SS430 dissolution were estimated and discussed. Furthermore, the SS430 surface is characterized using different techniques. The surface morphology of SS430 was tested utilizing several techniques. The experimental data were supported by the theoretical data.


Author(s):  
Khudhair Abbas Kareem Al-Rudaini ◽  
Khulood Abid Saleh Al-Saadie

This study will be investigating acidic corrosion of AA7051 alloy at a different temperature, and introduces milk thistle aqueous extract as a new and widely available green corrosion inhibitor. The electrochemical methods were used to measure weight loss, penetration loss, corrosion inhibition efficiency and other parameters. The data substituted in Langmuir adsorption isotherm as well as in kinetic equations. The finding exhibit high corrosion inhibition efficiency at 0.5g/L of milk thistle extract and the efficiency rose from around 72% at 293K to just over 86% at 333K. Langmuir model linear regression coefficient ( =0.98) and the slight change in corrosion potential refer to mixed-type inhibitor attach to the surface by chemisorption. FTIR spectra for crude extract supported by literatures shows the molecular structure of the main component of milk thistle extract and exhibit the O-H group as a major group participate in adsorption.


2021 ◽  
Vol 1045 ◽  
pp. 231-236
Author(s):  
Femiana Gapsari ◽  
Andita Ganda

The anti-corrosion characteristic of the extract of Psidiumguajava leaves on aluminum in 3.5 wt% sodium chloride were examined using electrochemical measurement. The thermodynamic factors such as the free energy adsorption, change in enthalpy, and entropy was also analyzed. The adsorption isotherm was detail described to study the adsorption of the inhibitor on the aluminum surface with various concentrations of the inhibitor. The electrochemical measurement was done through the potentiodynamic polarization test. The results show that the inhibitor act as the mixed type inhibitor and its adsorption on the aluminum surface obeys Temkin adsorption isotherm. The study suggests that the use of Psidium guajava leaves extract for the food industrial application is eco-friendly and safe, especially in salt solution medium.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Sarra Aourabi ◽  
Majid Driouch ◽  
Mariya Kadiri ◽  
Noura Achnine ◽  
Mouhcine Sfaira ◽  
...  

The synergetic effects between hydroethanolic extracts of A. visnaga HE (AV) and Z. mays hairs HE (ZM) on corrosion of mild steel in 1 M HCl solution was investigated at 298 K by two techniques: potentiodynamic polarization (PP) methods (Tafel and Stern & Geary) and electrochemical impedance spectroscopy (EIS). The mixture of HE (AV)/HE (ZM) acted as an efficient corrosion inhibitor and its inhibition efficiency increased with concentration up to 96.55% at 0.01 gL−1 HE (AV)/0.2 gL−1 HE (ZM). The polarization curves revealed that the mixture acted as a mixed-type inhibitor, with anodic predominant action. The EIS studies were fitted by the (Rs + CPEdl)/(Rct + CPEf/Rf) equivalent circuit model. The kinetic parameters were in favor of a physisorption character of adsorption of HE (AV)/HE (ZM) components onto the mild steel surface. The influence of exposure time on the efficiency of mixture extract was investigated. Scanning electron microscopy (SEM/EDX) analyses confirmed the formation of a protective adsorbed film upon the mild steel surface.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Aimad Mazkour ◽  
Souad El Hajjaji ◽  
Najoua Labjar ◽  
El Mostapha Lotfi ◽  
Mohammed El Mahi

The use of 5-azidomethyl-7-morpholinomethyl-8-hydroxyquinoline (AMH) as a corrosion inhibitor for AISI 321 stainless steel in 5.5 M polluted phosphoric acid was investigated using the hydrogen evolution technique, linear polarization curves, and impedance spectroscopy. Impedance measurements revealed that the dissolution of AISI 321 in 5.5 M polluted phosphoric acid was controlled by an activation mechanism, unchanged even with the addition of AMH at different concentrations. Polarization results showed that the inhibition ability was enhanced with increasing inhibitor concentration. AMH acted as a mixed-type inhibitor by random adsorption on the alloy surface, whatever the nature of the reaction that is taking place. The adsorption of AMH on the AISI 321 surface was also discussed via the Langmuir adsorption isotherm. The influence of elevating the solution temperature on the corrosion inhibition performance was studied. A quantum chemistry study with the DFT method was also conducted, which supplied a logical and exploitable theoretical explanation of the adsorption and the inhibition action of AMH on AISI 321.


2021 ◽  
Vol 13 (9) ◽  
pp. 769-784
Author(s):  
Tao Lu ◽  
Yi Liu ◽  
Yan Liu ◽  
Hao Chen ◽  
Chengang Han ◽  
...  

Aim: Butyrylcholinesterase (BChE) is a crucial therapeutic target because it is associated with multiple pathological elements of Alzheimer’s disease (AD). An integrated computational strategy was employed to exploit effective BChE inhibitors. Methods & results: Ten compounds derived from the Enamine database by structure-based pharmacophore virtual screening were further evaluated for biological activity; out of the ten, only five had an IC50 of less than 100 μM. Among these five compounds, a new molecule, 970180, presented the most potency against BChE, with an IC50 of 4.24 ± 0.16 μM, and acted as a mixed-type inhibitor. Molecular dynamic simulations and absorption, distribution, metabolism and excretion prediction further confirmed its high potential as a good candidate of BChE inhibitor. Furthermore, cytotoxicity of molecule 970180 was not observed at concentrations up to 50 μM, and the molecule also showed a prominent neuroprotective effect compared with tacrine at 25 and 50 μM. Conclusion: This study provides an effective structure-based pharmacophore virtual screening method to discover BChE inhibitors and provide new choices for the development of BChE inhibitors, which may be beneficial for AD patients.


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2399
Author(s):  
Mohammed Hamed Alqarni ◽  
Ahmed Ibrahim Foudah ◽  
Magdy Mohamed Muharram ◽  
Nikolaos E. Labrou

Human glutathione transferase A1-1 (hGSTA1-1) contributes to developing resistance to anticancer drugs and, therefore, is promising in terms of drug-design targets for coping with this phenomenon. In the present study, the interaction of anthraquinone and diazo dichlorotriazine dyes (DCTD) with hGSTA1-1 was investigated. The anthraquinone dye Procion blue MX-R (PBMX-R) appeared to interact with higher affinity and was selected for further study. The enzyme was specifically and irreversibly inactivated by PBMX-R, following a biphasic pseudo-first-order saturation kinetics, with approximately 1 mol of inhibitor per mol of the dimeric enzyme being incorporated. Molecular modeling and protein chemistry data suggested that the modified residue is the Cys112, which is located at the entrance of the solvent channel at the subunits interface. The results suggest that negative cooperativity exists upon PBMX-R binding, indicating a structural communication between the two subunits. Kinetic inhibition analysis showed that the dye is a competitive inhibitor towards glutathione (GSH) and mixed-type inhibitor towards 1-chloro-2,4-dinitrobenzene (CDNB). The present study results suggest that PBMX-R is a useful probe suitable for assessing by kinetic means the drugability of the enzyme in future drug-design efforts.


2021 ◽  
pp. 363-372
Author(s):  
Khudhair Abbas Kareem Al-Rudaini ◽  
Khulood Abid Saleh Al-Saadie

The aqueous extract of milk thistle (Silybum marianum) leaves as a green corrosion inhibitor for AA7051 aluminum alloy in sodium hydroxide solution was investigated at a range of temperatures. Potentiodynamic polarization findings exhibit a mixed–type inhibitor with directly increased inhibition efficiency with the concentration of inhibitor. The adsorption of the inhibitor on aluminum alloy obeys Langmuir isotherm and the kinetic as well as thermodynamic parameters were measured and discussed.


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