Trifenylmethane Compounds as Copper Corrosion Inhibitors in Hydrochloric Acid Solution

Fuchsin basic (FB) and fuchsin acid (FA) were tested as new corrosion inhibitors for copper in 0.001, 0.005, and 0.01 M hydrochloric acid (HCl) solutions. Benzotriazole (BTA) was also tested for comparative purposes. Twelve FB, FA, and BTA concentrations, from 1 × 10⁻⁵ M to 1 × 10⁻¹ M, were added to the acid solution at four temperatures ranging from 298 K to 328 K. Gravimetric measurements were performed after 3 h experimentation. The order of inhibition efficiency was FB ∼ BTA > FA. The Frumkin isotherm gave the best fit to the experimental results. The projected molecular area was used to elucidate inhibitor orientation in the adsorption process.