Imidazolium ionic liquid bearing urea moiety as a new corrosion inhibitor of mild steel

Experimental and computational studies of cationic Gemini surfactants as corrosion inhibitors for carbon steel in 15% HCl

In the process of oil and gas exploration, the corrosion of carbon steel pipes results in substantial economic losses, numerous casualties, environmental contamination, and resource waste. The advancement of highly efficient and stable corrosion inhibitors holds significant importance for protecting carbon steel from corrosion during oil and gas exploitation. In this study, two new cationic Gemini surfactants (2CncoesT, where n = 12, 14) were synthesized through a straightforward two-step reaction. Weight-loss tests demonstrated that the inhibition efficiency (ηw%) increases with the increase in temperature. Specifically, the maximum ηw% values for 2C12coesT and 2C14coesT were 98.0% and 98.3% respectively at 85 °C. The adsorption of these surfactants conformed to the Langmuir adsorption isotherm. Electrochemical measurements suggested that the two surfactants functioned as mixed-type inhibitors. The findings obtained from scanning electron microscopy (SEM) were consistent with the experimental outcomes that 2C12coesT and 2C14coesT are efficient corrosion inhibitors for the metal in an acidic environment. The quantum chemical investigation and molecular dynamics simulation (MD) further substantiated the experimental results and offered insights for a deeper comprehension of the inhibition mechanism of Gemini surfactants.

Influence of anionic alkyl chain on the tribological properties of titanium alloy under water lubrication: Experimental analysis and molecular dynamics simulations

In this work, four types of protic ionic liquids were prepared for use as pure water additives to investigate the effect of anionic alkyl chains on the tribological and drilling performance of a titanium alloy. Copper block immersion tests and electrochemical tests were conducted to compare their corrosion resistance. The results indicate that the ionic liquid containing OH and CC in the anionic alkyl chain led to stronger adsorption onto the metal substrate, providing excellent tribological performance and the highest corrosion inhibition rate (η = 98.45 %). According to density functional theory, wear scar surface analysis, and molecular dynamics simulation, the low energy gap of the anion (ΔE = 0.033 Ha) indicated that it exhibited higher reactivity. Thus, it was more susceptible to frictional chemical reactions with the metal substrate under the action of frictional heat during shearing, ultimately forming a friction film with a thickness of 20-97 nm. The ionic liquid demonstrated good wetting properties in a drilling test, enabling its effective penetration into the gaps between the drill bit and the workpiece to achieve lubrication and cooling effects. Thus, the axial force and drilling temperature were significantly reduced. Additionally, biotoxicity tests indicated that the ionic liquid is an environmentally friendly substance.

Corrosion mitigation in desalination plants by ammonium-based ionic liquid

CuNi (90:10) alloy is widely used in desalination plants. CuNi alloy corrosion in sulfide-containing seawater is the fundamental problem in the desalination industry. Here we have confronted this difficulty by using ammonium-based ionic liquid (Diethyl (2-methoxyethyl)-methyl ammonium Bis(fluorosulfonyl)imide) [DEMEMA][FSI]. The results revealed that the [DEMEMA][FSI] can suppress Cu–Ni alloy corrosion in a solution of (3.5% NaCl + 10 ppm sulphide) with an efficiency of 98.4% at 120 ppm. This has been estimated by electrochemistry and gravimetry. Furthermore, [DEMEMA][FSI] inhibits the growth of sulfate-reducing bacteria SRB in saline water. Surface morphology testing confirmed [DEMEMA][FSI] adsorption on Cu–Ni surface alloys. In addition, quantum calculations have been used to theoretically predict inhibition efficiency [DEMEMA][FSI].

Improving the sustainability of biodiesel by using imidazolium-based ionic liquid

Corrosion of biodiesel-filled fuel tanks has become a major problem in the use of biodiesel as a new green energy source. The ionic liquid 1-Hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C₁₀H₁₉N₂]⁺[C₂F₆NO₄S₂]⁻ was used to control corrosion of C-steel in non-edible biodiesel to resolve this problem. The anti-corrosion and antioxidant properties of the [C₁₀H₁₉N₂]⁺[C₂F₆NO₄S₂]⁻ were characterized using weight loss, electrochemical impedance spectroscopy, total acid number measurements beside SEM and EDX analysis. The findings show that [C₁₀H₁₉N₂]⁺[C₂F₆NO₄S₂]⁻ plays an important role in preventing C-steel corrosion in biodiesel with an efficiency close to 99 percent. The adsorption capability and antioxidant properties of [C₁₀H₁₉N₂]⁺[C₂F₆NO₄S₂]⁻ are the major contributors to the ionic liquid's anti-corrosion properties. We anticipate that this work will help to sustainable expand the use of biodiesel as a renewable energy source.