Scale and corrosion inhibition performance of the newly synthesized anionic surfactant in desalination plants: Experimental, and theoretical investigations

Ring opening reaction was used to prepare novel anionic surfactant as CaSO4.2H2O scale and mild steel (MS) corrosion inhibitor. The prepared surfactant was designed as Hexa-anionic surfactant, and named; Sodium(2Z,16Z)-8,11-bis((Z)-3-carboxylatoacryloyl)-5,14-bis(2-((4dodecylphenyl)sulfonamido)ethyl)-4,15-dioxo-5,8,11,14-tetraazaoctadeca-2,16-dienedioate. The Hexa-anionic surfactant was characterized by FTIR, and 1HNMR. Platinum ring method was used to study surface active properties of the investigated surfactant. The anti-scale property of Hexa-anionic surfactant was evaluated according to a static test method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) were used to examine CaSO4·2H2O crystal morphology. The high anti-scale performance of Hexa-anionic surfactant was related to its chelating, adsorption, and dispersion abilities. The scale inhibition (SI%) reached the maximum 100% at concentration 7 ppm. Also, the inhibition performance of the insight surfactant for MS corrosion in synthetic water was tested by electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP) techniques, accompanied with surface analysis techniques. The obtained results indicated a good corrosion mitigation action of the investigated surfactant. SEM, and EDX show the formation of Hexa-anionic surfactant's adsorbed layer on the MS surface. The adsorption of Hexa-anionic surfactant at MS followed Langmuir adsorption isotherm. Quantum calculations confirmed the experimental data.