Use of a Gemini-Surfactant Synthesized from the Mango Seed Oil as a CO2-Corrosion Inhibitor for X-120 Steel

Synthesis of Gemini-type imidazoline quaternary ammonium salt using by-product fatty acid as corrosion inhibitor for Q235 steel

Gemini-type imidazoline quaternary ammonium salt is a new type of environmentally friendly corrosion inhibitor has been widely used in engineering materials. However, most of them are hazardous/toxic compounds derived from petroleum-based products, which did harm to environment. In this work, an environmentally friendly Gemini-shaped imidazoline quaternary ammonium salt corrosion inhibitor (G211) was synthesized using cheap fatty acid recycled from dimer acid industry as feedstock. The corrosion inhibition effects of G211 on Q235 steel in 1 M HCl solution were investigated through weight loss experiments, potential polarization curves, and alternating current impedance spectroscopy experiments. The results show that the inhibition rate of G211 as a mixed-type inhibitor is up to 94.4% and the concentration drop as low as 500 ppm at 25 ℃. The adsorption of G211 on Q235 surface follows Langmuir adsorption isothermal curve. The chemical composition of the Q235 steel surface was analyzed through scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Furthermore, the possible corrosion inhibition mechanism of G211 on the surface of Q235 steel is proposed. This article not only presents an outstanding solution for safeguarding Q235 steel against corrosion but also introduces a feasible method for high-value utilization of monomer acid (MA).

Developing novel imidazoline-modified glucose derivatives as eco-friendly corrosion inhibitors for Q235 steel

Many natural compounds and imidazoline derivatives have been previously evaluated as eco-friendly corrosion inhibitors for application in the food, pharmaceutical and chemical industries. Herein, a novel alkyl glycoside cationic imaginary ammonium salt (FATG) was designed via the grafting of imidazoline molecules into the skeleton of a glucose derivative, and its effects on the electrochemical corrosion behavior of Q235 steel in 1 M HCl were systemically investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curves (PDP), and gravimetric measurements. The results indicated that its maximum inhibition efficiency (IE) was 96.81% at a concentration as low as 500 ppm. The adsorption of FATG on the Q235 steel surface followed the Langmuir adsorption isotherm. The scanning electron microscopy (SEM) and diffraction X-ray (XRD) results suggested the formation of inhibitor film on the metal surface, which significantly impeded the corrosion of Q235 steel. Additionally, FATG showed a high biodegradability efficiency (98.4%), which had great potential as a green corrosion inhibitor based on concepts of greenness and biocompatibility.

Inhibition of X52 Corrosion in CO2-Saturated Brine by a Dialkyl-Diamide from Coffee Bagasse Oil

This work reports the performance of a green corrosion inhibitor with double hydrocarbon chain. The evaluated inhibitor was a dialkyl-diamide from coffee bagasse oil and its electrochemical behavior was evaluated on an API-X52 steel in CO₂-saturated brine at 60 °C. The electrochemical behavior was determined by measurements of open circuit potential, polarization resistance, and electrochemical impedance spectroscopy. In addition, the thermodynamic parameters of the corrosion process were obtained in the temperature range from 40 °C to 80 °C. Electrochemical studies showed that the inhibitor is capable of suppressing metal dissolution by up to 99% at 25 ppm. On the other hand, the thermodynamic parameters indicate that when adding the inhibitor, there is a strong increase in both Ea and ΔH° values, and that as time increases, they decrease until reaching similar values to those observed in the absence of the inhibitor. Furthermore, ΔS° values tend to become more negative with immersion time because of the formation of a stable film on the metal surface.