Evaluation of Green Corrosion Inhibition by Extracts of Citrus aurantium Leaves Against Carbon Steel in 1 M HCl Medium Complemented with Quantum Chemical Assessment

Employing plants as corrosion inhibitors is a physical direction to detect less expensive green friendly inhibitors. Researchers found that the Citrus aurantium leaves extracts are mixtures containing vitamins, minerals, phenolic compounds and terpenoids. The flavonoids contained in C. aurantium can be divided into four groups, including flavones, flavanones, flavonols, and anthocyanins. These compounds indicate the extracts of Citrus aurantium leaves are appropriate to be applied as green corrosion inhibitors. Extracts of Citrus aurantium leaves have been researched by utilizing EIS, gravimetric and SEM techniques as novel eco-friendly corrosion inhibitors for carbon steel in corrosive environments. Inhibition effectiveness of tested extract depends on different concentrations of extract, starting from 0 to 40% v/v. Inhibition effectiveness of 81.2% is reached at the concentration of 20% v/v of the extract in 1 M corrosive solution for three hours at 25℃. Temperature effects and activation parameters have been investigated. A theoretical investigation of Citrus aurantium leaves extract isomers as corrosion inhibitors have been done using DFT/ B3LYP density functional theory. The results shows that, in general, Citrus aurantium leaves have good inhibiting activities at relatively low concentrations. Phenolic groups of Citrus aurantium leaves were picked for examination as substituents of the four inhibitors. Hydroxyl groups of the studied extract compounds result in an increase in inhibition effectiveness, while methylation of the hydroxyl group leads to decrease in inhibitive effectiveness. Citrus aurantium leaves extracted isomers symbolize a considerable enhancement in the inhibition performance

Synthesis, Characterization, and Corrosion Inhibition Potential of Novel Thiosemicarbazone on Mild Steel in Sulfuric Acid Environment

Corrosion of a material by reaction with a corrosive environment is a common problem across many industries. Iraq is an oil country and corrosion represents a large portion of the total costs for oil producing and a natural potential hazard associated with oil production and transportation. The synthesis of novel thiosemicarbazone, namely 2-(2,4-dimethoxybenzylidene)hydrazinecarbothioamide (DMBHC), was conducted and the chemical structure was elucidated via the 1H and 13C NMR (Nuclear magnetic resonance), and FT-IR (Fourier-transform infrared) spectroscopic spectroscopic techniques in addition to carbon, hydrogen, and nitrogen analyses (CHN analyses). The inhibition properties of the investigated thiosemicarbazone were evaluated for mild steel (MS) corrosion in 1N H2SO4 using electrochemical impedance spectroscopy (EIS), weight loss method, and scanning electron microscopy (SEM). Electrochemical and weight loss techniques revealed that the tested thiosemicarbazone acted as a superior inhibitor for the acidic corrosion of MS and the efficiency increased with increasing concentrations. The EIS results revealed that thiosemicarbazone demonstrated the highest inhibition efficiency of 94.86%, at a concentration of 0.5 mM. Results from the weight loss technique suggested that the thiosemicarbazone acted as a mixed type corrosion inhibitor. The impact of temperature on the mechanism of inhibition of the new synthesized inhibitor of the surface of MS in 1N H2SO4 was investigated at various temperatures (30–60 °C) where the inhibitive efficiency diminished with increasing temperatures. The mechanism of inhibition was additionally verified with the methodological data

Synthesis and corrosion inhibition application of NATN on mild steel surface in acidic media complemented with DFT studies

The corrosion inhibition effectiveness of thiosemicarbazide compound, namely 3-nitro-5-(2-amino-1,3,4-thiadiazolyl)nitrobenzene (NATN), on mild steel in 1 M hydrochloric acid media has been investigated by weight loss technique. The results exhibit that the corrosion ratio of mild steel was reduced regarding to adding NATN. The corrosion inhibition rate for the NATN was 92.3% at the highest investigated NATN concentration. From the weight loss results it could be concluded that NATN with sulfur, nitrogen and oxygen atoms has clarified best corrosion inhibition achievement comparing to 3,5-dinitrobenzoic acid. Regarding to theoretical studies, DFT was employee to figured geometrical structure and electronic characteristics on NATN. The investigation have been extensive to the HOMO and LUMO analysis to evaluate the energy gap, Ionization potential, Electron Affinity, Global Hardness, Chemical Potential, Electrophilicity, Electronegativity and Polarizability. Keywords: NATN, Mild steel, Weight loss, Dinitrobenzoic aci