تحضير وتشخيص دقائق السيلينيوم النانوية المطعمة بالبوليمرات ودراسة كفاءتها في تثبيط تآكل الفولاذ الكربوني

Synthesis and characterization of selenium nanoparticles grafted with polymers and study of their efficiency in inhibition corrosion of carbon steel.

Polyvinyl alcohol-stabilized selenium nanoparticles (PVA-SeNPs) and chitosan-stabilized selenium nanoparticles (Ch-SeNPs) were prepared by chemical reduction method using ascorbic acid as the reducing agent. The nanoparticles were characterized using XRD, DLS, Zeta Potential, FT-IR, and TEM analysis. The first evidence of the formation of selenium nanoparticles changes the color of the solution from colorless to orange, TEM microscopic images showed that the selenium nanoparticles were spherical in shape with an average diameter of 42.14 nm and 59.8 nm for (PVA-SeNPs , Ch-SeNPs), respectively. In addition to the fact that XRD confirmed the crystalline and amorphous nature of the nanoparticles, FT-IR analysis showed the Se-Se metallic bond at 720 cm-1, which confirms the formation of Nano selenium (SeNPs). A solution of (Ch-SeNPs, PVA-SeNPs) was used as corrosion inhibitors for carbon steel in 1.0 M H2SO4. The effect of the presence of inhibitors in the corrosion medium was studied by potential polarization (electrochemical studies) using the Tafel technique and the weight loss method. The corrosion inhibition efficiency reached 92.86% in the presence of PVA-SeNPs at a concentration of 600 ppm, and 93.02% in the presence of Ch-SeNPs 500 ppm at a temperature of 303 K. The results of electrochemical studies indicate that selenium nanoparticles stabilized with chitosan (Ch-SeNPs) give better inhibition efficiency at a lower concentration than selenium nanoparticles stabilized with polyvinyl alcohol (PVA-SeNPs). It was found that increasing the concentration increases the efficiency of inhibition, and temperature has a negative effect, the lowest inhibition efficiency reached 65.67% and 62.35% for (PVA-SeNPs , Ch-SeNPs), respectively, at a concentration of 100 ppm and a temperature of 323 K. The inhibition of the corrosion process was confirmed by studying the metal surface of the samples used using SEM and AFM techniques, which showed that the effect of the acidic medium on the surface of carbon steel was significantly reduced in the presence of (Ch-SeNPs, PVA-SeNPs). Adsorption isotherms (Freundlich, Langmuir, Temkin) were studied for the studied inhibitors on the metal surface, and it was found that Langmuir adsorption is the most suitable with a spontaneous adsorption process of the mixed type (chemical and physical adsorption). The kinetic and thermodynamic functions of the inhibition process were also studied.