Bioinspired snapping-claw apparatus to study hydrodynamic cavitation effects on the corrosion of metallic samples

A creative low-cost and compact mechanical device that mimics the rapid closure of the pistol shrimp claw was used to conduct electrochemical experiments, in order to study the effects of hydrodynamic cavitation on the corrosion of aluminum and steel samples. Current-time curves show significant changes associated with local variations in dissolved O2 concentration, cavitation-induced erosion and changes in the nature of the surface corrosion products

Electrochemical Study of Interaction between Imidazole-Based-Ionic-Liquid and Light Petroleum in Oil/Water Emulsion

In the present work, the binding capacity of a 1-methyl-3-hexylimidazolium p-toluenesulfonate ionic liquid to Aragon light oil within a 70/30 oil/water emulsion was studied by cyclic voltammetry. The imidazole-based ionic liquid was synthesized by anion interchange reaction. Its chemical structure was confirmed by Fourier-Transform Infrared Spectroscopy and Nuclear Magnetic Resonance. Its Critical Micelle Concentration (CMC) in water was determined by Conductimetry, Ultraviolet-Visible Spectroscopy and Cyclic Voltammetry. The ionic-liquid-to-oil binding-constant and binding-free-energy were determined from the dependence of the voltammogram anodic-peak-current with the ionic liquid concentration in the emulsion. The diffusion coefficient of the free and bound forms of the oil within the emulsion were determined from the Randles-Sevcik equation. The measurements led to a CMC value of approximately 152 mg/L and a binding constant of 0.98x104 M-1, corresponding to a binding free energy of -22.78 KJ/mol. The negative value of the latter confirmed the ionic liquid spontaneously binds to the oil phase. The oil-droplets diffusion coefficient showed a 2.5-fold increase (up to 4.631x10-7 cm2/s) due to incorporation of the ionic liquid molecules. The information gathered can be helpful to design more efficient remediation processes of oil-contaminated water, as well as to improve the design of ionic liquid molecules, and to study their interaction with different oil components

The Steel-Aluminum Galvanic System under Thin Electrolyte Films: Simulation and Validation

Modern manufacturing combines conventional materials, such as structural steel, with lighter materials (e.g., aluminum and magnesium alloys) increasing the risk of galvanic corrosion. The present work applies advanced numerical methods and a novel experimental technique for tracking chemical species during galvanic interactions. The model hereby developed predicts the transient distribution of corrosion products generated during the galvanic corrosion of a carbon steel/aluminum alloy system. The model considers a micrometric electrolyte layer containing ten interactive chemical species. It was solved by the finite element method (FEM). The fundamental contribution of the model was the use of an extra source term in the mass conservation equation to avoid meshing limitations, especially when working with extremely thin domains

The corrosion products in a carbon steel/aluminum alloy galvanic couple under thin electrolyte films: An efficient model

An electrochemical model was developed to predict the transient distribution of species generated during corrosion of a carbon steel/AA7075 aluminum alloy galvanic couple. Both metals were set under a confined electrolyte layer of thickness 50 μm containing ten interacting chemical species. The model was solved by the finite element method. The main contribution of the model is the use of an extra source term within some governing equations to avoid solving for the O concentration in extremely thin domains. The solution is rendered as top-view instead of the usual cross-sectional one. The whole model provides both a light computational code and a robust approach to the phenomenon under study. Transient experimental pH measurements were achieved with the help of an innovative setup implemented for micrometric electrolyte layers. The experimental and predicted pH fronts had an acceptable level of agreement.This work has been financed by the UNAM-DGAPA-PAPIIT program (TA100318). A.R.G. acknowledges the Conacyt scholarship. Authors acknowledge the support of LIMO and PND laboratories from PUNTA-UNAM.Peer Reviewe