A Revisit to the Corrosion Inhibition of Aluminum in Aqueous Alkaline Solutions by Water-Soluble Alginates and Pectates as Anionic Polyelectrolyte Inhibitors

Table 3

Activation parameters for corrosion of Al in alkaline media in absence and presence of some added inhibitors. [OH⁻] = 4.0 and I = 4.0 mol dm⁻³.

Inhibitor	[Inhibitor]; mol dm^−3	Parameter
		Δ𝐻^≠; kJ mol^−1	Δ𝑆^≠; J mol^−1 K^−1	Δ𝐺^≠; kJ mol^−1	𝐸𝑎^≠; kJ mol^−1	𝐴; mol^−1 s^−1
Alginate	0.0	58.85	+61.97	77.31	61.15	1.11×10^11
	0.01	66.61	−30.64	75.74	69.03	4.14×10^11
	0.03	63.60	−44.10	76.74	66.17	8.71×10^11
Pectates	0.0	58.85	+26.71	77.31	61.15	1.11×10^11
	0.01	64.94	−38.45	76.40	67.51	1.72×10^11
	0.03	61.48	−54.23	77.64	64.05	2.57×10^10