INVESTIGATION OF THE INHIBITION OF LOW CARBON STEEL CORROSION IN A SULPHURIC ACID SOLUTION BY LEAF' EXTRACT/OF INDIAN COPPER LEAF (ACAFYPHA INDICA)

ABSTRACT The performance of flower extract of Acalypha indica (Indian copper leaf) in protecting low carbon steel against corrosion in sulphuric acid medium was investigated using weight loss experiments with the aim of determining its applicability, effectiveness and efficiency in corrosion inhibition. Mild steel coupons of known dimensions, compositions and weights with drilled cylindrical holes were fully submerged into six corrosion cells each containing 0.5 M solution of sulphuric acid as aggressive solution. Five of the corrosion cells contained, in addition to the aggressive solution, varying concentration of the leaf extract, while the remaining cell was left blank to serve as the control experiment. The weight losses were monitored for a period of 78 consecutive hours at a temperature of 303 K. The weight loss data obtained were used to determine the corrosion rate and percent inhibition efficiency of the leaf extract with respect to each corrosion cell. Results obtained revealed that the Acalypha indica leaf extract (AILE) effectively retarded the corrosion of the low carbon steel coupons in the acid solution at the stated temperature. In the absence of the leaf extract (i.e. the blank cell), the corrosion rate of 19.650 mm/yr was recorded. But with only 0.1 g/L of the leaf extract, the corrosion rate was drastically reduced to 4.083 mm/yr. This accounted for a percent inhibition efficiency of 79.22% which increased to 95.67% at 0.5 g/L of the extract. This showed that the AILE is a good corrosion inhibitor for low carbon steel at the stated temperature.