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

Table 3

The weight loss and electrochemical polarization measurements of API X52 carbon steel in 1 M HCl with addition of synthesized inhibitors A312, A314, and A316 at 25°C.

Surfactant	Concentration; (ppm)	Electrochemical Polarization					Weight Loss
		Icorr,; mA cm^−2	Ecorr,; mV	ßa,; mV dec^−1	ßc,; mV dec^−1	Ep %	Corr. Rate; (mg.cm^−2.hr^−1)	Ew%
Blank	0.00	801.75	-510.9	226.0	259.8	0.00	0.4903	0.00
A312	1.00	551.12	-528.0	220.4	228.2	31.26	0.3462	29.37
	5.00	402.31	-504.2	172.6	193.5	49.82	0.2628	46.38
	10.0	261.41	-494.0	175.1	208.3	67.39	0.1441	70.60
	20.0	142.15	-518.0	168.1	195.1	82.27	0.0772	84.25
	25.0	119.86	-523.0	150.1	170.1	85.05	0.0633	87.07
	50.0	55.080	-512.1	142.2	167.4	93.13	0.0447	90.86
	100.0	48.185	-514.8	130.5	160.5	93.99	0.0289	94.10
	200.0	46.260	-514.4	128.2	157.0	94.23	0.0251	94.87
A314	1.00	610.85	-533.0	216.9	226.5	23.81	0.3728	23.95
	5.00	428.57	-505.3	180.7	199.5	46.54	0.2888	41.07
	10.0	359.08	-500.4	172.9	207.0	55.22	0.2054	58.13
	20.0	215.26	-501.2	167.8	188.6	73.15	0.1310	73.29
	25.0	180.47	-493.7	149.3	174.0	77.49	0.1109	77.36
	50.0	91.311	-502.1	149.3	167.2	88.64	0.0693	85.86
	100.0	74.322	-507.5	143.8	157.3	90.73	0.0402	91.80
	200.0	96.832	-502.9	127.0	155.6	91.29	0.0366	92.52
A316	1.00	624.80	-526.8	225.8	236.4	22.07	0.3842	21.63
	5.00	536.02	-522.3	221.9	234.0	33.14	0.3193	34.86
	10.0	361.90	-527.8	215.7	226.2	54.86	0.2265	53.78
	20.0	295.76	-514.9	180.0	198.6	67.60	0.1611	67.13
	25.0	244.85	-512.3	181.7	204.9	69.46	0.1425	70.92
	50.0	171.97	-519.3	170.1	188.1	78.55	0.1019	79.19
	100.0	119.94	-490.2	150.2	173.9	85.04	0.0732	85.06
	200.0	82.820	-523.8	165.4	174.2	89.67	0.0505	89.69