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Keywords

Carboxymethyl cellulose, Graphite, Silica nanoparticles, Inhibition, EIS

Document Type

Article

Abstract

This work aims to inhibit carbon steel surface as pipelines by adding carboxymethyl cellulose (CMC) with three concentrations (1, 3 and 5 g/L) in seawater environment at four temperatures in the range of 298 – 328 K. The investigation was done by recording Tafel plots and EIS curves to show that the lowest concentration is the best to protect the steel surface with efficiencies ranged between 95.68 – 89.36 % that decrease with increasing temperature due to the decomposition of CMC that begin after ≈ 308 K. An attempt to enhance the protection by CMC at higher temperature has been done by adding 0.1 g/L graphite and 1 g/L silica, the results of electrochemical measurements indicated the good role of graphite and silica through the sheet structure of graphite (Gr) that enhance the CMC by the formation of multi layers of (Gr/CMC/Gr/CMC) which theoretically studied through density functional theory (DFT) in addition to calculate some electronic parameters, while the silica nanoparticles (S) gave an important role to pre-treatment the steel surface to form a passive layer on surface and within CMC polymer. The inhibitive role of Gr. and S. is attributed to higher mobility and Zeta potential of two additives compared with that for CMC. From the data of EIS test, 1 g/L CMC recorded the highest value for resistance of solution (Rs) and resistance of charge transfer (Rct). Scanning electron microscopy with energy dispersive X-ray confirmed the adsorption of inhibitive materials by appearance O and C elements in inhibition by CMC and then increases with addition Gr., while decreases with addition Silica and appear Si element.

DOI

10.30684/2412-0758.2409

First Page

139

Last Page

165

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