Table 4 Azadirachta indica as corrosion inhibitor
Concise manner | Metal | Plant product | Solution | Effect of temperature on percentage inhibition efficiency | Effect of concentration on percentage inhibition efficiency | Methods | Adsorption type and isotherm used | Reference |
|---|---|---|---|---|---|---|---|---|
Mature leaves extract of neem reported as a green corrosion inhibitor for Zn in HCl medium by the use of gravimetric and thermometric methods | Zn | Mature leaves of neem | HCl | Decrease | Increase | Gravimetric and thermometric | Physical adsorption | Sharma et al. 2010c |
Dry seed extract of AZI reported as a good inhibitor for mild copper corrosion in HNO3 medium by weight loss and phytochemical analysis. Obtained results show that percentage inhibition efficiency increase with increasing concentration and show mixed type inhibition | Mild copper | Dry seeds extracts of AZI | HNO3 | Decrease | Increase | Weight loss and phytochemical analysis | Mixed-type adsorption. | Sangeetha and Fredimoses 2011 |
There were selected plants [Occimum viridis (OV), Telferia occidentalis (TO), Azadirachta indica (AZI), Hibiscus sabdariffa (HS), Garcinia kola (GK)] which extracts reported as good corrosion inhibitors for mild steel corrosion in HCl and H2SO4 by gasometric method. Obtained results indicate that all the extracts inhibited the corrosion process in both acid media and the presence of halide additive increase inhibition efficiency due to synergistic effect | Mild steel | AZI + halide additive | HCl and H2SO4 | No dependence | Increase | Kinetics activation parameters and gasometric technique | – | Oguzie 2008 |
It is reported that AZI with iodide additive shows good inhibition for Al corrosion in HCl medium by PDP method. Due to synergistic effect, the adsorption was spontaneous and followed the Freundlich adsorption isotherm | Al | AZI and iodide ions as | HCl | Decrease | Increase | PDP techniques | Freundlich adsorption isotherm | Arab et al. 2008 |
Azadirachta indica extract reported as an effective inhibitor for steel corrosion in the acid media by the gas volumetric techniques and obtained results show that consistence of Langmuir adsorption isotherm | Mild steel | AZI extracts | Different concentrations of HCl | Decrease | Increase | Gas volumetric technique | Langmuir isotherm adsorption (mixed inhibitor) | Oguzie 2006 |
AZI reported as Al corrosion inhibitor in HCl medium by the use of weight loss and thermometric methods. Obtained results show that adsorption was exothermic, spontaneous, and obeyed the Freundlich, Temkin, and Flory-Huggins | Al | AZI | HCl | Decrease with rise in temperature | Increase | Weight loss and thermometric | Freundlich, Temkin, and Flory-Huggins | Ebenso et al. 2004 |
AZI leaves reported as a corrosion inhibitor for mild steel in H2SO4 medium by the use of weight loss technique | Mild steel | AZI leaves | H2SO4 | – | – | Weight loss technique | Physical adsorption | Ebenso et al. 1998 |
Ethanolic extract of AZI fruit reported as a good inhibitor for aluminum corrosion in HCl medium by the use of weight loss thermometric method. Obtained results show the presence of physical adsorption process like percentage inhibition efficiency increase with increasing concentration but decrease with rise in temperature and followed Langmuir adsorption isotherm | Al | Ethanolic extract of AZI fruit | HCl | Decrease with rise in temperature | Increase | Weight loss thermometric | Langmuir adsorption isotherm | Sharma et al. 2013 |
AZI mature leaf extract reported as good inhibitor for mild steel corrosion in HNO3 medium by the use of gravimetric method. Obtained results show that percentage inhibition efficiency increased with increasing concentration but get down with the rise in temperature. Adsorption process was exothermic and consistent and best fitted into Frumkin adsorption isotherm | Mild steel | AZI mature leaf extract | HNO3 | Decrease with rise in temperature | Increase | Gravimetric techniques | Frumkin adsorption isotherm | Sharma et al. 2010d |
UAE neem extract reported as a good inhibitor for carbon steel corrosion in HCl medium by the use of weight loss method and obtained results show that percentage inhibition efficiency increase with increasing inhibitor concentration but decrease with rise in temperature and data was fit into Temkin adsorption isotherm | Carbon steel | UAE neem extract | HCl | Decrease with rise in temperature | Increase | Weight loss method | Temkin adsorption isotherm | Ayssar et al. 2010 |
The inhibition effect of AZI extract reported as good inhibitor on stainless steel corrosion in HCl and H2SO4 medium by the weight loss method. Obtained results show that extract of AZI was better inhibitor as compare with other extract | Stainless steel | Plant extract | HCl + H2SO4 + tetraoxosulphate (IV) acid + trioxnitrate (V) acid solution | Decrease at high temperature | Increase | Weight loss method | Physical adsorption | Obiukwu et al. 2013 |
It is reported that ethanol extract of leaves and seeds of A. indica shows its effective inhibition effect on mild steel corrosion in H2SO4 medium by the use of gasometric, gravimetric, and IR methods. Corrosion inhibition efficiency of the leaves is better than that of the seeds .According to findings, the reaction followed the physical adsorption and fit in Flory-Huggins adsorption isotherm | Mild steel | Ethanol extracts of seeds and leaves | H2SO4 | Decrease | Increase | Gravimetric, gasometric, and IR methods | Flory-Huggins adsorption isotherm | Eddy and Mamza 2009 |
It is reported that the inhibition effect of AZI extract on mild steel corrosion in acidic medium was good but it’s more clearly visible in HCl medium as comparison with H2SO4 solution. In HCl medium the percentage inhibition efficiency was increase with increasing concentration of inhibitor but it gets down on high temperature. Obtained results show the physical adsorption performance | Mild steel | Extract of AZI leaf | HCL and H2SO4 | Decrease with rise in temperature | Increase | Weight loss and PDP method | Physical adsorption | Loto et al. 2011 |
Neem leaf extract reported as a good corrosion inhibitor for mild steel in chloride medium by the gravimetric method. It showed a comparison with or without neem leaf extract in salty water medium with heat treatment. IE increased with the increasing concentration of inhibitor in chloride- and heat-treated chloride medium but its decreased without inhibitor in chloride- and heat-treated chloride medium | Mild steel | Extract of AZI leaf | Chloride (salty water medium) | Increase in neem + chloride medium but decrease in only-chloride medium | Increase in neem + chloride medium but decrease in only-chloride medium | Gasometric | – | Tuaweri et al. 2015 |
Neem bark reported as efficient corrosion inhibitor for mild steel in HCl medium by the use of PDP method. Percentage IE efficiency increased with increased concentration but decreased with the rise in temperature and reported data fit into Langmuir adsorption isotherm | Mild steel | Neem ark | HCl | Decrease with rise in temperature | Increase | Potentiodynamic polarization | Langmuir (mixed-type inhibition ) | Desai 2015b |