Adsorption Properties and Inhibition of C38 Steel Corrosion in Hydrochloric Solution by Some Indole Derivates: Temperature Effect, Activation Energies, and Thermodynamics of Adsorption

Table 6

Thermodynamic parameters calculated from IES for the adsorption of indole derivates in 1 M HCl on the C38 steel at different temperatures.

Con. (mM)	Norharmane			Harmane
	𝐸𝑎 (kJ mol^−1)	Δ𝐻𝑎 (kJ mol^−1)	Δ𝑆𝑎 (J mol^−1 K^−1)	𝐸𝑎 (kJ mol^−1)	Δ𝐻𝑎 (kJ mol^−1)	Δ𝑆𝑎 (J mol^−1 K^−1)
HCl	28.00	26.87	−131.04	—	—	—
0.2	32.78	31.65	−120.35	29.03	27.91	−131.68
0.4	33.34	32.22	−116.44	32.82	31.69	−121.55
0.8	38.00	36.87	−105.77	34.05	32.92	−119.20
1.2	38.77	37.64	−104.36	37.05	35.92	−110.91