Inhibition of corrosion of ASTM A192 steel in hydrochloric acid solution by the mucilage of <i>Linum usitatissimum</i>

Zavaleta-Gutierrez, Nilthon Emerson; Polo-Briceño, Elmer Rolando; Siche, Raúl; Angelats-Silva, Luis Manuel

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Artículos • Matéria (Rio J.) 23 (02) • 2018 • https://doi.org/10.1590/S1517-707620180002.0390 copy

Inhibition of corrosion of ASTM A192 steel in hydrochloric acid solution by the mucilage of Linum usitatissimum

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

In this study, the inhibition of the corrosion of ASTM A192 steel in HCl 0,5 M at temperature different, by the Linum usitatissimum mucilage, was investigated using techniques: Tafel extrapolation, linear polarization resistance, electrochemical impedance spectroscopy and electrochemical frequency modulation.

The Linum mucilage acts as an optimum corrosion inhibitor of ASTM A192 steel in HCl. The average inhibition efficiency obtained with the evaluated techniques were of 84,3% at 25 °C, 89,0% at 45 °C and 91,8% at 65 °C, with a concentration of the mucilage of 1 g/l. It was found that the efficiency of inhibition and the adsorption constant increased with increasing temperature. The standard enthalpy of adsorption was positive and the apparent activation energy decreased with the increase of the concentration of the mucilage. All these parameters indicate that the adsorption of flaxseed mucilage in steel evaluated occurs through a chemical adsorption. In addition, as the temperature increases, mucilage behavior changes from an anodic inhibitor to a mixed-type inhibitor.

Keywords
Linum usitatissimum; ASTM A192 steel; acid inhibition; EIS; EFM

C	Si	Mn	P	S	Cu
0,14	0,16	0,53	0,008	0,024	0,21

T (^oC)	ML (g/l)	i_{corr (EFM)} (µA/cm²)	β_a (mV/década)	-β_c (mV/década)	V_corr (mm/año)	EI_EFM (%)	CF (2)	CF (3)
25	0,00	150,78	84,09	89,91	1,751	0,00	2,352	3,089
	0,01	98,21	91,33	99,03	1,140	34,86	2,067	3,359
	0,05	61,69	105,08	116,08	0,716	59,09	2,124	2,976
	0,10	40,16	106,43	141,70	0,466	73,37	2,032	3,226
	0,50	35,33	112,56	134,84	0,410	76,57	2,003	2,890
	1,00	34,54	129,27	166,70	0,401	77,09	1,882	2,894
45	0,00	614,22	86,47	103,00	7,131	0,00	1,990	2,922
	0,01	298,47	84,70	101,72	3,465	51,34	1,937	3,035
	0,05	176,80	93,17	110,63	2,053	71,21	1,931	3,243
	0,10	155,93	92,35	134,75	1,810	74,62	1,926	2,930
	0,50	95,88	119,50	153,00	1,113	84,39	1,953	2,985
	1,00	84,69	110,50	137,00	0,983	86,22	1,954	3,161
65	0,00	2833,94	85,67	110,53	32,902	0,00	2,021	3,162
	0,01	1388,51	92,08	113,20	16,121	51,01	1,982	3,088
	0,05	691,90	86,38	111,15	8,033	75,59	1,929	3,077
	0,10	511,26	89,89	132,20	5,936	81,96	1,964	2,988
	0,50	341,77	97,79	167,85	3,968	87,94	1,964	3,281
	1,00	251,02	92,72	143,50	2,914	91,14	1,971	2,968

T	ML	R_p	i_{corr (Rp)}	V_{corr (Rp)}	EI_Rp
(^oC)	(g/l)	(Ω.cm²)	(mA/cm²)	(mm/año)	(%)
25	0,00	131,12	144,68	1,680
	0,01	223,23	92,48	1,074	41,26
	0,05	472,05	51,14	0,594	72,22
	0,10	686,77	38,57	0,448	80,91
	0,50	888,33	30,14	0,350	85,24
	1,00	1116,69	28,35	0,329	88,26
45	0,00	32,02	646,66	7,508
	0,01	64,44	311,47	3,616	50,32
	0,05	123,39	178,17	2,068	74,05
	0,10	146,83	162,59	1,888	78,19
	0,50	295,56	99,25	1,152	89,17
	1,00	333,76	79,59	0,924	90,41
65	0,00	7,45	2825,34	32,802
	0,01	14,08	1565,59	18,176	47,13
	0,05	29,86	707,83	8,218	75,06
	0,10	41,56	561,12	6,515	82,08
	0,50	79,46	337,68	3,920	90,63
	1,00	93,31	363,97	3,065	92,02

T (^oC)	ML (g/l)	R_s (Ω.cm²)	R_ct (Ω.cm²)	n	C_dl (µF/cm²)	i_{corr (EIS)} (µA/cm²)	V_{corr (EIS)} (mm/año)	EI_EIS (%)
25	0,00	0,81	134,10	0,944	87,25	141,43	1,642
	0,01	0,56	225,80	0,940	87,08	91,37	1,061	4,61
	0,05	0,48	438,47	0,923	66,44	54,98	0,638	69,42
	0,10	0,38	697,80	0,917	63,09	37,90	0,440	80,78
	0,50	0,38	893,26	0,904	58,12	29,94	0,348	84,99
	1,00	0,44	1077,98	0,904	51,92	29,36	0.341	87,56
45	0,00	0,50	32,50	0,953	125,23	629,40	7,307
	0,01	0,26	63,78	0,964	120,15	314,76	3,654	49,05
	0,05	0,39	119,66	0,930	83,41	183,34	2,128	72,84
	0,10	0,36	141,88	0,932	81,58	168,46	1,956	77,10
	0,50	0,32	318,41	0,912	49,89	91,55	1,063	89,79
	1,00	0,39	336,18	0,906	46,52	79,01	0,917	90,33
65	0,00	0,26	7,68	0,995	288,12	2794,86	32,45
	0,01	0,34	15,27	0,968	190,12	1443,86	16,76	49,71
	0,05	0,37	29,98	0,942	147,31	704,40	8,18	74,38
	0,10	0,36	43,44	0,931	120,59	535,03	6,21	82,32
	0,50	0,30	78,40	0,913	57,66	342,22	3,97	90,20
	1,00	0,35	98,18	0,918	56,75	252,22	2,93	92,18

T (°C)	Mucílago de linaza (g/l)	Grado de protección (θ)
T (°C)	Mucílago de linaza (g/l)	Técnica EFM	Técnica Rp	Técnica EIS
25°C	Blanco	0,000	0,000	0,000
	0,01	0,349	0,413	0,406
	0,05	0,591	0,722	0,694
	0,10	0,734	0,809	0,808
	0,50	0,766	0,852	0,850
	1,00	0,771	0,883	0,876
45° C	Blanco	0,000	0,000	0,000
	0,01	0,513	0,503	0,490
	0,05	0,712	0,741	0,728
	0,10	0,746	0,782	0,771
	0,50	0,844	0,892	0,898
	1,00	0,862	0,904	0,903
65° C	Blanco	0,000	0,000	0,000
	0,01	0,510	0,471	0,497
	0,05	0,756	0,751	0,744
	0,10	0,820	0,821	0,823
	0,50	0,879	0,906	0,902
	1,00	0,911	0,920	0,922

Temperatura (^oC)	Intercepto (1/k)	Pendiente	k	Coef. de correlación lineal (R²)
Técnica EFM
25	0,01461	1,281	68,44	0,9999
45	0,01389	1,149	71,98	0,9999
65	0,01299	1,090	76,99	0,9997
Técnica Rp
25	0,01430	1,124	69,91	0,9998
45	0,01340	1,093	74,64	0,9999
65	0,01276	1,075	78,34	0,9999
Técnica EIS
25	0,01463	1,131	68,36	0,9998
45	0,01393	1,092	71,77	0,9999
65	0,01300	1,074	76,94	0,9999

Temperatura	Técnica electroquímica			Promedio
(^oC)	EFM	Rp	EIS
	ΔG^o_ads (kJ/mol)
25	-27,771	-27,824	-27,768	-27,79
45	-29,571	-29,667	-29,563	-29,60
65	-31,620	-31,669	-31,618	-31,64
	ΔH°_ads (kJ/mol)
25	2,610	2,527	2,622	2,586
45	2,610	2,527	2,622	2,586
65	2,610	2,527	2,622	2,586
	ΔS°_ads (J/mol)
25	101,271	101,171	101,301	101,248
45	101,198	101,238	101,211	101,216
65	101,272	101,171	101,301	101,248

ML (g/l)	Técnica	Factor pre-exponencial A (mm/año)	Energía de activación E*_a (kJ/mol)	Coeficiente de regresión lineal
0,00	EFM	3,67 x 10¹¹	65,10	0,9984
	Rp	5,08 x 10¹¹	65,95	0,9999
	EIS	4,26 x 10¹¹	65,56	0,9999
	Promedio	4,34 x 10¹¹	65,54
0,01	EFM	1,80 x 10¹⁰	58,76	0,9817
	Rp	8,42 x 10¹⁰	62,75	0,9854
	EIS	3,11 x 10¹⁰	60,08	0,9962
	Promedio	4,44 x 10¹⁰	60,53
0,05	EFM	1,47 x 10⁹	53,63	0,9878
	Rp	8,16 x 10⁹	58,30	0,9978
	EIS	4,43 x 10⁹	56,59	0,9985
	Promedio	4,69 x 10⁹	56,17
0,10	EFM	3,22 x 10⁹	56,46	0,9977
	Rp	1,02 x 10¹⁰	59,42	0,9969
	EIS	7,86 x 10⁹	58,76	0,9905
	Promedio	7,09 x 10⁹	58,21
0,50	EFM	2,27 x 10⁸	50,34	0,9893
	Rp	7,47 x 10⁸	53,61	0.9997
	EIS	8,59 x 10⁸	54,05	0.9947
	Promedio	6,11 x 10⁸	52,67
1,00	EFM	1,77 x 10⁷	44,00	0.9930
	Rp	1,32 x 10⁸	49,50	0.9956
	EIS	3,19 x 10⁷	45,83	0.9984
	Promedio	6,05 x 10⁷	46,44

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E-mail: revmateria@gmail.com

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[1] Nilthon E. Zavaleta-Gutierrez