Methionine derivatives as green corrosion inhibitors: Review

This review exposed the inhibitory effect of methionine as green compound and its derivatives. The efficacy of these kind of molecules is related to two combined groups: amine and carboxylic acid as well as the presence of sulphur atom. Search on Scopus showed that a hundred publications in various aggressive solutions as HCl, H2SO4, H3PO4, HNO3, NaCl. The corrosion of iron, aluminium, lead, copper, nickel, tin … can be retarded using methionine derivatives which adsorbed on several kind of adsorption isotherms depending on the nature of metal/solution interface

The Environmental Impacts of Generated Air Pollution in Omdurman Industrial and Residential Area, Khartoum State, Sudan.

Industrial pollution is considered as one of the most important sources of environmental pollutants, which may have negative impacts on the human health and environment. This study is conducted with the aim of identifying environmental impacts resulting from air pollutants in Omdurman industrial and residential areas in Khartoum state. The study adopted a scientific method including, environmental measurement of air pollutants (carbon monoxide, sulfur dioxide, nitrogen dioxide, volatile organic compounds and particulate matter). These pollutants were measured in nine different sites during  the winter and summer seasons of 2012 including two samples per season. The study revealed the following results: the carbon monoxide ( CO) concentration average range was 0 to 7.9 ppm, which fits the allowed locally limits (22.6 ppm) and internationally (35 ppm). Regarding SO2 and NO2, their average concentration ranged between 0 to 0.4 and 0 to 0.27 respectively, and it is also classified within the locally allowed  limits( 11.8 and 26.6ppm) and internationally ( 2 and 20 ppm)  during the entire year. The average concentration of  volatile organic carbon(VOCs) in different locations were between 449 to 2526 ppb which exceeded the  limits of permited value (750 ppb). The average values of the particulate matter were from 1.11 to 27.78 ppm which exceeds the international limits of 9 ppm

Green inhibition of carbon steel corrosion by fish oil in hydrochloric acid medium

Corrosion is a major problem of the  destruction of various materials, especially metals. The highest effect of corrosion processes increased during pollution. The environmental toxicity of organic corrosion inhibitors has prompted the search for green corrosion inhibitors as they are biodegradable, do not contain heavy metals or other toxic compounds and readily available and renewable. The effect of fish oil as a green inhibitor of carbon steel corrosion has been investigated in a 1 M hydrochloric acid solution using polarization curves, electrochemical impedance spectroscopy (EIS) and gravimetric techniques. The obtained results reveal that fish oil effectively inhibits the corrosion of carbon steel. The highest inhibition efficacy value is 91.82% obtained by potentiodynamic polarization and 92.96% by electrochemical impedance spectroscopy at the maximum concentration tested. The inhibition efficiency increased with increasing concentration of tested oil, although he's remainder stable with increasing temperature. The polarization curves show that the tested oil can be considered as a mixed type inhibitor and that the absorption of the inhibitor on the carbon steel electrode obeys the Langmuir isotherm. The EIS results indicate that changes in impedance parameters are related to the adsorption of fish oil on the surface of the alloy

Inhibition of Mild Steel Corrosion in 1M Hydrochloric Medium by the cherimoya seeds

In the present study, the inhibition performance of mild steel by cherimoya seeds extract was investigated using weight loss measurements, electrochemical techniques, and scanning electron microscope (SEM) coupled with energy‐dispersive X‐ray spectroscopy (EDX). The experimental data suggested that the cherimoya seeds exhibited a high inhibition performance, which increases with increasing their concentrations. Cherimoya seeds extract present maximum inhibition efficiency of 94%  at an optimal concentration of 1g/L. The principal observations that resulted from electrochemical studies are that cherimoya seeds affected both anodic and cathodic reactions (mixed inhibitors). Their adsorption, which is a combination of chemisorption and physisorption, obeyed the Langmuir isotherm model. Furthermore, the temperature effect was carried out at various temperatures ranging from 303 to 328 K to verify the corrosion inhibition performance of cherimoya seeds at higher temperatures. Moreover, SEM‐EDX analysis confirmed that cherimoya seeds can ensure remarkable prevention against corrosion through the adsorption onto the metal surface

Disappearance of Azoxystrobin and difenoconazole in green beans cultivated in Souss Massa valley (Morocco)

A study was undertaken to evaluate the degradation behavior and residue levels of azoxystrobin and difenoconazole in Belma green beans variety grown in an experimental plastic greenhouse. The measurements were made over a 3 week period in which up to two successive treatments with azoxystrobin and a 5 week period in which up to two successive treatments with difenoconazole were carried out. Residue levels of dicofol and difenoconazole were determined by Gas chromatography with electron capture detection (GC-ECD), liquid-liquid extraction (LLE), solid phase extraction (SPE) and high-performance liquid chromatography (HPLC). During the study, residue levels in the plantation ranged between 0.35 and 0.01 mg/kg for azoxystrobin and between 0.25 and 0.01 mg/kg for difenoconazole. The residual concentrations after the preharvest intervals (PHI) were below the legal limits

Effect of amino acid on the passivation, corrosion and inhibition behavior of aluminum alloy in alkaline medium

The effect of L-methionine (L-Met) on the passivation and corrosion inhibition of aluminum alloy was investigated in carbonate medium in presence of chloride ions. This inhibitive action against the corrosion of aluminum in corrosive solution was investigated at 298 K using potentiodynamic polarization curves (PDP), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results obtained from the polarization curves reveal that the aluminum in alkaline medium exhibits a phenomenon of passivation with breakdown of passivity. Temperature effect on the corrosion behavior with the addition of (L-Met) studied in the range of temperature from 298 to 328 K. The inhibition efficiency decreases slightly with the increase in the temperature. Results show that L-Met is a good inhibitor and inhibition efficiency reach 87,23% at 10−3M. The electrochemical results are confirmed by scanning electron microscopy (SEM). The adsorption of this compound on aluminum surface obeys Langmuir’s adsorption isotherm. The kinetic and thermodynamic parameters were determined and discussed

Corrosion behaviour of steel rebar: effect of simulated concrete pore solution and chloride ions

In this work, we investigate the corrosion behavior of steel rebar (SR) in four simulated concrete pore solutions (CPS): NaOH+KOH (CPS1), Na2CO3 (CPS2), NaOH (CPS3) and Ca(OH)2 (CPS4) medium.  Effect of addition of Cl- anions as pollutant on pitting and uniform corrosion of SR is investigated by using potentiodynamic polarization (PDP) technic. The result obtained show that uniform and pitting corrosion of SR are strongly influenced by the nature of simulated CPS. In unpolluted CPS’s, only uniform corrosion of SR is observed in all cases. SR has excellent corrosion resistance in CPS4 compared to the other simulated CPS. In the polluted CPS’s by Cl- anions, we observe an accelerated uniform corrosion especially in CPS1, CPS3 and CPS4 mediums. The sensitivity to localized corrosion of SR varies from one simulated environment to another. It has the best resistance to pitting corrosion in polluted CPS3 medium. In CPS1 (pH = 13) and CPS2 (pH = 11.6) polluted by 3% NaCl, the tendency to pitting corrosion is the same. The localized attack is more pronounced in polluted CPS4 (pH=12.7). These results demonstrate that there are no limit values of the pH and the content of Cl- ions for the initiation of pitting and / or uniform corrosion. Therefore, it is the chemical composition of the simulated medium which imposes the pH value and the Cl- content for systematic corrosion study of the SR in the simulated CPS

Removal of methylene blue from industrial wastewater in Palestine using polysiloxane surface modified with bipyrazolic tripodal receptor

Different pollutants from industries leach every day to soil and ground waters without treatment. The product N,N-bis (3,5-Dimethylpyrazol-1-yl methyl)-3-aminopropyl Polysiloxane (Si-C3H6NPz2) was successfully prepared. The FTIR results confirmed that the dimethylpyrazole units have been immobilized onto the surface of the modified silica gel. The adsorption experiments were conducted for a wide range of solution pH, adsorbent dosage, temperature, initial concentration and contact time. It was observed that the percentage removal of methylene blue dye decreased with an increase initial concentration and temperature while it increased with increase in solution pH, contact time and adsorbent dose. Over 82% removal efficiency of methylene blue dye was achieved after 180 min at solution pH around 10, 20°C temperature, 0.25 g weight of dose and initial concentration of 15 mg/L of 50mL MB dye solution. Negative ∆G° values (-17.17 to -17.25 KJ/mol) indicate that the adsorption is favorable and spontaneous at these temperatures. The negative value of ∆H° (-16.66 KJ/mol) reflects an exothermic adsorption and indicates that the adsorption is favored at low temperature. The value of ∆H° was higher than those corresponding to physical adsorption. This would suggest that the adsorption process is chemical in nature. The small positive value of ∆S° (+1.78 J/mol.K) suggests that some structural changes occur on the adsorbent and the randomness at the solid/liquid interface in the adsorption system increases during the adsorption process. The results of the present study show that the prepared compound has a negative biological activity against Pseudomonas aeruginosa, Staphylococcus aurous, and Escherichia coli

Electrochemical and thermodynamic study of the inhibitory efficacy of Methanol extracts of the Rind and Leaves of Grapefruit plant on the corrosion of carbon steel in an acidic medium

The inhibition potentials of methanol extracts of leaves (GFL) and rind (GFR) of Grapefruit plant was investigated by evaluating the corrosion behaviour of carbon steel metal immersed in 1.0 M HCl solution containing various concentrations of the extracts. Electrochemical technical, Gravimetric measurements and adsorption characterization were utilized to evaluate the corrosion inhibition and adsorption properties of the extracts. The results revealed that the studied extracts were efficient inhibitors of corrosion in carbon steel immersed in 1.0 M HCl and that the inhibition efficiency depends on the concentration of the extracts. The activation energies and the negative free energy of adsorption obtained from the adsorption of methanol extracts of leaves and rind of Grapefruit indicate that the methanol extracts were physically adsorbed on the surface of the carbon steel and that the adsorption is endothermic, spontaneous, strong and fit excellently with the assumptions of the Langmuir adsorption isotherm. The activation parameters are determined and discussed.