Abstract
The inhibition efficiency of plumbago europaea extract on the corrosion of aluminum in 1.0M NaOH was investigated using weight loss technique. The presence of plumbago europaea extract inhibited the corrosion of aluminum in the test solution. The inhibition efficiency increased with increasing plant concentration and increased with increasing temperature and reaches a maximum value of 96.8% with the highest extract concentration 20 ppm at 50 degrees C. The experimental data complied to langmuir, temkin and the recently formulated thermodynamic/kinetic model of adsorption isotherms. The obtained value and sign of the standard free energy of adsorption is consistent with physisorption isotherms.