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The pitting corrosion of SS-316L in human body fluid leads the metallic prosthesis to lose its strength along with severe health consequences such as metallosis condition. Hence, an effective alternative for enhancing the biocompatibility of the SS-316L implant is the electrochemical deposition of a bioinert hydroxyapatite (HAP) coating over the metallic surface. A dense HAP coating was successfully developed on SS-316 L in a supersaturated electrolyte containing Ca+2 and PO43− ions. Electrochemical essays and SEM morphological observation showed the SS-316 L pitting corrosion caused by chloride containing body fluid. The effects of the electrodeposition time and the temperature of the supersaturated electrolyte were assessed using current–time transients, scanning electron microscopy, Energy-dispersive X-ray spectroscopy, Raman and X-ray diffraction analyses. The increase in the temperature promotes the HAP coating formation and accelerates the particles nucleation. An instantaneous HAP growth with no evidence for intermediate phase of HAP formation has been noticed.

This work deals with the study of the inhibition activity of three thiazolidinones (prepared from monoterpenic ketones) on the deterioration of S300 steel in hydrochloric acid solution. The potenti...

Under the effect of acidic exposure, stainless steel structures of industrial equipment are constantly losing their corrosion resistance, and consequently leading to extensive damage. With the aim of protecting stainless steel equipment from the general corrosion in sulfuric acid, we investigate the inhibitory effect of Dittrichia viscosa extract and the main isolated sesquiterpenes. Potentiodynamic polarization and AC electrochemical impedance are used to demonstrate the efficiency of the tested inhibitors. For a better understanding of the molecular properties and the inhibitory potential of each sesquiterpene, quantum chemical calculations are performed using a hybrid method of B3LYP function with 6-31G (d, p) basis set. The present study provides comprehensive results proving the inhibitory effect of sesquiterpenes on the corrosion of stainless steel in sulfuric acid. The inhibition efficiency of tomentosin attains 95% at 7.5 × 10−5 mol/L. The adsorption data of tomentosin fit well the Langmuir isotherm, while the thermodynamic study substantiates its chemical adsorption. Quantum chemical calculations suggest the reactive sites of interaction and corroborate the experimental findings. The present work might help to understand the corrosion behaviour of stainless steel in sulfuric acid and the inhibitory potential of different sesquiterpenes.

The removal potential of slow sand filtration was investigated in a continuous fixed-bed adsorption system as a replacement of current expensive methods for decontaminating water. This study was achieved on Tensift River water contaminated by metallic trace elements (Cd, Cu, Pb and Zn) that received directly wastewater of industrial unit of Zn and Pb extraction of Draa Lasfar mine near Marrakech city in Morocco. Results showed that removal efficiency of sand used in this process depends greatly on both sand porosity and diameter of column. Thus, higher decontamination efficiency was noted at higher column’s diameter and higher sand porosity. These results can be justified by the fact that higher diameter of column and sand porosity engenders a higher mass transfer zone due to an increase coefficient diffusion and longer contact time as well as shallow adsorption zone with exposition of new active binding sites to metallic pollutants on the sand surface. This result provides a larger service area leading to an increase in the volume of the treated solution water. In order to describe the column adsorption process used in slow sand filtration, it is crucial to predict the breakthrough curve (concentration-like profile) and adsorption capacity of sand under the given set of operating conditions (sand porosoty and diameter of column), based on the assumption that this process follows Langmuir kinetics of adsorption–desorption with no axial dispersion which describes that the rate driving force obeys the 2nd order irreversible reaction kinetics.