INHIBITIVE EFFECT OF HYPTIS SUAVEOLENS (L) POIT EXTRACT AND NATURAL HONEY ON CORROSION OF MILD STEEL IN H2SO4 SOLUTION

In this present study, inhibitive effects of a hybrid corrosion inhibitor, formulated from hyptis suaveolens poit extract and honey, on mild steel in H2SO4 solution was investigated using potentiodynamic polarization method. The extract and honey were characterized using Gas chramatogahy - Spectrometer (GC - MS) to determine the active components responsible for corrosion inhibition. Hyptis Suaveolens L Poit extract and Honey were blended in percentage ratios (extract: honey) of 25:75, 50:50, and 75:25 accordingly. A test electrolyte of 1M solution of H2SO4 was used in the absence and presence of varying concentrations of the inhibitor (0, 2, 4, 6, 8 and 10 %) were carried out. Linear Tafel of the anodic and cathodic curves were extrapolated using corrosion potential to obtain the corrosion current densities (Icorr), corrosion potential (Ecorr), anodic Tafel slope (ßa) and cathodic Tafel slopes (ßc). GC - MS spectra of hyptis suaveolens poit extract and honey revealed 13 (13 peaks) different compounds for the extract and 11 (11 peaks) for honey which are compounds that were found to be responsible for corrosion inhibition. The anodic and cathodic current densities for the blends in different ratios, were found to decrease by increasing the blended inhibitor's concentrations. The blend with 75% Extract and 25% Honey gave the highest inhibitors efficiency of 87.5 % at a concentration of 6 % with minimum corrosion rate. The absorption of the hybrid inhibitors on the mild steel were observed to obey Langmuir adsorption isotherm.