Utilization of A Diallylmethylamine-Based Cyclopolymer for Low Carbon Steel Corrosion Control in Strong Acid Medium

摘要

A novel random copolymer made from diallylmethylamine and N1,N1-diallyl-N1-methyl-N6,N6,N6-tripropylhexane-1,6-diammonium dibromide monomers was investigated as a corrosion inhibitor forlow carbon steel in strong acid (15% HCl) environment. The corrosion inhibition studies wasperformed using gravimetric, electrochemical impedance spectroscopy (EIS), potentiodynamicpolarization (PDP) and linear polarization resistance (LPR) techniques complemented by theanalysis of the metal specimen surfaces exposed to uninhibited and inhibited corrosive solutionsusing scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDAX), atomicforce microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. The influenceof addition of small amount (1 mM) of iodide ions (KI) on the corrosion inhibition performance of thecopolymer was also assessed. Results obtained indicate that the copolymer acts as effectivecorrosion inhibitor for low carbon steel in the aggressive acid environment particularly at elevatedtemperatures. Optimum concentration (500 ppm) of the copolymer afforded inhibition efficiency of78.9 and 83.7% at 25 and 60 oC respectively. Addition of KI to the copolymer has profound effecton the corrosion inhibition performance raising inhibition efficiency from 78.9% to 92.9% at 25 oC.The enhanced corrosion inhibition of the copolymer by iodide ions is due to synergistic effect asconfirmed from the calculated synergistic parameter which was found to be greater than unity.Corrosion mitigation is by chemisorption mechanism and can be best described using both theLangmuir and El-Awady et al. kinetic-thermodynamic adsorption isotherms. Surface analysisresults confirm adsorption of additive molecules on steel surface. The copolymer is a promisingcorrosion inhibitor for oil well acidization operations.