Inhibitory Action of Artemisia annua Extracts and Artemisinin on the Corrosion of Mild Steel in H₂SO₄ Solution

Table 4

Thermodynamic parameters for the adsorption of EEAA, AEAA, TEAA, and ATS on mild steel in 5 M H₂SO₄ (using the gasometric technique).

Inhibitor	Equilibrium constant				Δ𝐻^𝑜ads (KJmol^−1)	Δ𝑆^𝑜ads (Jmol^−1)
	30°C	40°C	50°C	60°C
EEAA	3.97	3.31	2.48	1.94	−20.37	−55.51
AEAA	5.92	4.42	3.27	2.03	−29.41	−81.89
TEAA	1.35	1.08	0.97	0.50	−25.50	−81.01
ATC	0.32	0.23	0.24	0.16	−17.22	−66.45