The goal of this thesis is to probe the functionality of 2-mercaptobenzimidazole (MBI) as corrosion inhibitor of carbon-steel in both strong and weak aqueous acidic solutions (HCl and H2CO3). To achieve this target electrochemical techniques have been employed, in combination with substrate analysis. Concerning aqueous HCl media, results demonstrate that MBI is an effective corrosion inhibitor, functioning essentially equally well in 1 M, 0.1 M, and 0.01 M HCl concentrations. X-ray photoelectron spectra suggest that MBI is typically bound to the surface in two tautomeric forms (thione and thiol). Furthermore, these data indicate that substrate termination varies as a function of both HCl and MBI concentration, with the interface consisting of MBI bound to film-free carbon-steel on highly inhibited substrates. In further work, the impact of dissolved oxygen, solution temperature, and immersion time on MBI performance in HCl solutions has been assessed. The latter two parameters have considerable influence on MBI inhibition efficiency. More specifically, it was found that MBI decreases dramatically its inhibition efficiency between 60°C and 70°C in 1 M HCl, and also apparently work less well as substrate immersion time increases. As regards MBI performance in deaerated CO2-saturated NaCl (0.62 M) solution, results demonstrate that MBI effectively inhibits corrosion within the parameter space explored i.e. solution temperatures of 30°C and 55°C and total applied pressures (p(H2O) + p(CO2)) of 1 bar and 20 bar. The performance of MBI does not vary greatly for different combinations of these temperatures and pressures. Post immersion substrate characterisation with XRD and SEM indicate that no significant surface scaling occurs under these conditions.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:607083 |
| Date | January 2013 |
| Creators | Morales Gil, Perla |
| Contributors | Cottis, Robert; Lindsay, Robert |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://www.research.manchester.ac.uk/portal/en/theses/exploring-corrosion-inhibition-in-acidic-and-oilfield-environments(a08cd84c-fa3a-4378-88dc-f467ac4f8f56).html |
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