Synthesis of Novel Gemini Surfactants Based on Succinic Acid and Their Application as Inhibitors for Carbon Steel Corrosion

Abstract

Three nonionic Gemini surfactants were synthesized based on succinic acid. The structures of the synthesized surfactants were characterized using FTIR and 1H NMR spectra. The physical properties such as surface tension ( $$\gamma$$ ), critical micelle concentration (CMC), surface pressure (effectiveness) ( $$\pi_{\text{CMC}}$$ ), maximum surface excess concentration (Γmax), and minimum surface area occupied by one molecule (Amin) were calculated. The inhibitive power of the surfactants toward acid corrosion of carbon steel was obtained using weight loss and electrochemical techniques. The morphology of the carbon steel surface was examined by atomic force microscope. It was found that all the three surfactants act as good inhibitors for steel corrosion in the acidic medium. The inhibition efficiency increases with increasing surfactant concentration and exposure time. The inhibition action was attributed to the adsorption of the surfactant’s molecules on the steel surface. It was found that the adsorption process is spontaneous and obeys Langmuir adsorption isotherm. A mechanism was proposed for the inhibition action based on the obtained results.