Antioxidant activity and effect of quince pulp extract on the corrosion of C-steel in 1M HCl

The inhibition effect of quince pulp extract (QPE) on the adsorption and corrosion of carbon steel in 1M HCl solution was investigated using the weight loss method, potentiodynamic polarization and impedance spectroscopy measurements. At first, the quince extract was characterized, its polyphenolic content was qualitatively and quantitatively determined and its anti-oxidant activity was assessed. The HPLC–DAD–MS showed that the quince extract contained a high quantity of polyphenols with the main compounds being neochlorogenic acid, rutin and chlorogenic acid (7.68, 9.05 and 18.57 mg/g fw, respectively), which represent together about 84 % of total phenolics. The extract exhibited a strong antioxidant potential as it inhibited 87 % of the DPPH· anionic radical. The polarization measurements indicate that the extract acts as a mixed inhibitor. The values of inhibition efficiency increase with inhibitor concentration reaching a maximum value (88 %) at 5 × 10−1 g/L. The presence of QPE enhances the values of R t and reduces the C dl values. The adsorption of QPE under consideration on a steel/acidic solution interface at all temperatures follows the Langmuir adsorption isotherm. The QPE inhibitor efficiency was temperature-independent.