Comparative studies on the corrosion inhibition efficacy of ethanolic extracts of date palm leaves and seeds on carbon steel corrosion in 15% HCl solution

The work reports on the study carried out to comparatively assess the corrosion \ninhibition efficacy of crude ethanolic extracts of date palm leaves and seeds on X60 \ncarbon steel corrosion in 15% HCl solution at 25–60 °C. The corrosion inhibition studies \nwas carried out using weight loss and electrochemical (potentiodynamic polarization \nand linear polarization resistance) techniques. Preliminary phytochemical screening was \nperformed in order to determine the phytoconstituents present in the crude extracts. The \ninfluence of extractive solvents on the corrosion inhibition performance of the extracts \nwas also investigated. It is found that the crude extracts of both date palm leaves and \nseeds contain saponins, flavonoids, cardiac glycosides and reducing sugars. Tannins is \nonly present in the leaves and absent in the seeds while anthraquinones is absent in \nboth extracts. The crude ethanolic extracts inhibited the corrosion of X60 steel in the \naggressive 15% HCl solution with the leaves extract showing superior performance. \nInhibition efficiency increased with increase in concentration of the extracts and \ntemperature. Potentiodynamic polarization results reveal that the extracts function as \nmixed type inhibitors. Corrosion inhibition occurs by virtue of adsorption of components \nof the extract on the steel surface and was found to follow Langmuir adsorption \nisotherm model. On the influence of the extractive solvents on the corrosion inhibition \nperformance, the order of inhibition efficiency at 60 °C follows the trend DPLAE (73.6%) \n> DPLEE (62.5%) > DPSAE (59.9%) > DPSEE (55.9%) with the optimum extract \nconcentration (2000 ppm) studied.