Liriope platyphylla extract as a green inhibitor for mild steel corrosion in sulfuric acid medium

Use of Trochodendron Aralioides Extract as Green Corrosion Inhibitor for Mild Steel in 1M HCl Solutions

Recently, there is an interesting discussion that has transpired around the world about the usage of plant extracts as corrosion inhibitors. We report that to control corrosion in mild steel (MS) specimens in a 1M HCl medium, Trochodendron aralioides (T. aralioides) extract was used as an economical green corrosion inhibitor. The various tests, namely, potentiodynamic polarization, weight loss measurements and electrochemical impedance spectroscopy (EIS) were performed to analyze the inhibition efficiency (IE) of the extract. The highest IE value of 96.42% was seen at 250 ppm, with the IE% increasing as the extract concentration increased. Potentiodynamic polarization suggests that T. aralioides plant extract acts as a mixed-type inhibitor. UV–visible (UV–Vis) and FT-IR spectroscopy were performed with the inhibitor to study the adsorption mechanism and surface analysis of the specimen, respectively. The results revealed that plant extracts form a protective film on the surface of the specimens, increasing inhibition and thereby reducing corrosion. Surface morphological studies such as AFM, EDX and SEM tests were performed in the presence and absence of the inhibitor with the results being analyzed by observing the surface of the metal.

Synthesis and inhibitive characteristic of two acryloyl chloride derivatives towards the corrosion of API 5L X52 carbon steel in hydrochloric acid medium

Two new organic based corrosion compounds were prepared from Acryloyl chloride are namely: N,N-bis(2-hydroxyethyl) acrylamide (DEA) and N-(2-hydroxyethyl) acrylamide (MEA). The prepared compounds were studied as corrosion inhibitors for carbon steel (CS) in 1 M hydrochloric acid solution while the efficiency of the prepared compounds were studied through different chemical (weight loss, WL) and electrochemical techniques [potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS)] in addition to, the theoretical techniques as Quantum chemical calculations, Monte Carlo simulation and the surface morphology study using atomic force microscopy (AFM). The obtained results showed that the investigated compounds are working as good corrosion inhibitors, the inhibition efficacy (%IE) increases with the increase of the compound concentrations. However, the %IE decreases with the rise in the temperature proving that the adsorption of the inhibitor molecules on the CS surface is physisorption, while the polarization data revealed that these compounds are classified as mixed kind inhibitors, that inhibits both anodic and cathodic reactions. Results reveal that DEA and MEA exhibit an excellent %IE of 89.2 and 71.6% at 60 ppm for DEA and MEA, respectively. The adsorption of the inhibitor molecules on CS surface following Langmuir adsorption isotherm. There is a strong matching between results obtained from experimental and theoretical studies. The order of the investigated inhibitors based on the %IE is DEA > MEA.

Evaluation of Antioxidant and Anticorrosive Activities of Ceriops tagal Plant Extract

Mangroves are plants known for their various medicinal and economical values, and therefore are widely investigated for their phytochemical, antioxidant, antidiarrheal, and antimicrobial activities. In the present study, we analyze the antioxidant and anticorrosive properties of Ceriops tagal (C. tagal), a tropical and subtropical mangrove plant of the Rhizophoraceae family. The total phenolic content (TPC) and total flavonoid content (TFC) were found to be 101.52 and 35.71 mg/g, respectively. The extract (100 µg/mL) exhibited 83.88, 85, and 87% antioxidant property against 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide, and hydrogen peroxide free radicals. In addition, 600 ppm of C. tagal extract showed 95% corrosion inhibition against 1 M HCl attack on mild steel at 303 ± 1 K, which declined over other concentrations and temperatures, where AAS produced 82% inhibition at 600 ppm. UV-visible spectroscopy analysis revealed the formation of an inhibitor metal complex. The elemental analysis provided the presence of 84.21, 9.01, and 6.37% of Fe, O, and C, respectively, in inhibited mild steel, whereas the same were 71.54, 22.1, and 4.34%, respectively, in uninhibited specimen, stressing the presence of protective film on the metal surface. Scanning electron microscopy (SEM) also showed some noteworthy changes in both uninhibited and inhibited mild steel, making C. tagal plant a better alternative than any other synthetic inhibitors. Further, the atomic force microscopy (AFM) surface topography analysis showed that 600 ppm of C. tagal extract significantly diminished corrosion on the surface of mild steel.