Abstract: In this paper, the effects of cyperus esculentus (tiger nut) leaves extract as corrosion inhibitor for mild steel in 0.5M NaCl solution was investigated. This is to replace the unfriendly, hazardous chromates, bromates, molybdates that have been used as corrosion inhibitors but harmful to lives. Weight loss method was used to study the corrosion behavior at the temperature range of 40 oC and 60 oC with inhibitor concentration from 0.1 – 0.5 g/l over an exposure period of 24 hours. The corrosion rates and inhibition efficiency were determined in the absence and presence of cyperus esculentus extract. The corrosion rates decreased with increase in inhibitor concentrations and the inhibition efficiency increased with increase in inhibitor concentration. But however, the inhibition efficiency decreased with increase in temperature. The trend of the result was used to propose the mechanism of inhibition. The inhibitor adsorption characteristic were approximated by Langmuir adsorption isotherm at all the temperatures and concentrations studied. The phenomenon of physical adsorption is proposed based on the thermodynamic parameters that govern the inhibition process.

 
Keywords: Cyperus esculentus, adsorption isotherm, chromates, molybdates, aqueous solution, NaCl

| DOI: 10.17148/IARJSET.2020.7525