Study of Corrosion, Scale Processes, and Development of Microorganisms and Their Inhibition in Moroccan Simulated Cooling Water

In this paper, in the first time, the characterization of corrosion and scale processes of the Moroccan simulated cooling water were investigated by using electrochemical impedance spectroscopy (EIS) coupled with Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Analysis (EDX). It is found that the simulated water has a corrosive and scale character. In fact, the sample surface was greatly damaged during the immersion tests, as the corrosion products show a multi-layer morphology. In addition, it is remarked that this surface shows heterogeneous layer of scale products, which confirmed by EDX analysis. Additionally, it is found that the mechanism of corrosion and scale phenomena depends on the cathodic and anodic overvoltage and electrode rotation. On the other hand, the effects of monosaccharide derivatives without and with molybdate were investigated using EIS technique. It is found that 436the enhanced inhibition efficiency caused by the addition of molybdate ions is only due to the synergistic effect. In addition, the effect of sodium gluconate (SG) was studied, and it found that the inhibition efficiency increases with its concentration. In addition, the influence of CTAB on corrosion and bio-corrosion of steel without and with SG was studied. It is seen that the obtained formulation SG/CTAB acts as a good inhibitor for corrosion, scale and biocorrosion. However, the effect of corrosion products, immersion time and chloride ions was investigated. It is obtained that the formulation takes its performance. Finally, in order to find the best formulation with a low cost, the interference between the two compounds SG and CTAB at different concentrations was studied. It is found that the beset formulation was composed of 5×10-3 M of SG with 15 ppm of CTAB (low concentration).