Inhibition of API 5L X52 Pipeline Steel Corrosion in Acidic Medium by Gemini Surfactants: Electrochemical Evaluation and Computational Study

Table 4

Electrochemical impedance spectroscopy (EIS) for the corrosion of API X52 steel in 1 M HCl at various concentrations of the synthesized inhibitors at 25°C.

Surfactant	Conc.; (ppm)	Rs; (Ω cm^2)	Cdl 10^∧-6; (Ω^–1.cm^–2 sn)	Rct; (Ω. cm^2)	Ei %
Blank	0.00	2.207	786	3.395	0.00
A312	5.00	2.191	412	7.859	65.89
	25.0	2.119	126	17.55	81.66
	50.0	2.433	87.0	31.46	89.21
	100.0	2.325	49.9	54.72	93.79
	200.0	2.175	48.1	65.44	94.81
A314	5.00	2.18	158	9.241	63.26
	25.0	1.987	170.6	16.5	79.42
	50.0	2.237	159.6	21.87	84.48
	100.0	2.073	131.8	29.72	88.58
	200.0	2.207	79.7	55.55	93.89
A316	5.00	2.034	269	7.031	51.71
	25.0	2.021	180	11.73	71.06
	50.0	1.885	119.5	15.79	78.50
	100.0	1.977	218	20.02	83.04
	200.0	2.11	146	32.66	89.60