N,N'-Bis-(2-aminoethyl)piperazine functionalized graphene oxide (NAEP-GO) as an effective green corrosion inhibitor for simulated acidizing environment

Abstract In this work we evaluated the corrosion inhibition efficacy of N,N'-Bis-(2-aminoethyl)piperazine functionalized graphene oxide (NAEP-GO) against carbon steel in 15% HCl which simulate oil well acidizing environment by weight loss (at ambient and higher temperatures) and electrochemical measurement experiments. The GO was synthesized using waste graphite, after which N,N'-Bis-(2-aminoethyl)piperazine was grafted onto the GO. Both the GO and NAEP-GO were characterized by FTIR, Raman and TEM techniques. The effect of concentration, temperature and time on the performance of the inhibitor was investigated in this study. The inhibitor efficiency was observed to increase with concentration and a maximum inhibition efficiency of 87% was observed for 25 ppm NAEP-GO at room temperature. The inhibitor exhibited excellent performance at the studied temperatures, however the performance decreases with increase in temperature. The inhibitor showed excellent efficiency of over 80% for all the studied immersion time. The PDP measurement revealed the NAEP-GO to acts predominantly as a cathodic-type inhibitor. The studied compound was observed to obey the Langmuir adsorption isotherm. SEM/EDS, AFM surface morphology and FT-IR analyses of the corrosion product after 24 hours’ immersion in the NAEP-GO inhibited solution provide evidence of adsorption of NAEP-GO molecules on the steel surface to form the protective NAEP-GO film that blocked the steel surface from the aggressive acid attack. This study is of importance in solving two main environmental problems, corrosion and the problem of waste disposal as GO was prepared from waste graphite.