Corrosion inhibition and adsorption properties of petiveria alliacea extract on brass in acid media

摘要

The objective of the present studies was to investigate the inhibitive effect of Petiveria alliacea extract (PAE) on the corrosion of a- brass in 0.5 M HCI by mass loss and thermometric measurement at various time intervals and temperature. Petiveria alliacea a medicinal plant, containing phytochemicals is rich in sulphur and oxygen atoms which generally serve as inhibitive adsorption centres. The corrosion rate is remarkably lower in acid environment containing PAE compared with those in extract free solution. The inhibition efficiency (70- %) is concentration and temperature dependent, increasing with increase in PAE concentration but decreasing with rise in temperature and time. The activation energy, free energy of adsorption and variation of inhibition efficiency with temperature for the adsorption of PAE on metal surface were computed and found to obey Langmuir and Frumkin adsorption isotherms. Thermodynamic parameters revealed the adsorption process was spontaneous. The significance of the studies showed that Petiveria alliacea can serve as a source of cheap, biodegradable and environmentally friendly corrosion inhibitor.