US EPA

1560333 

Journal Article 

1,2-Diaminoanthraquinone as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid: Weight Loss and Quantum Chemical Study 

Obi-Egbedi, NO; Essien, KE; Obot, IB; Ebenso, EE 

2011 

Yes 

International Journal of Electrochemical Science
ISSN: 1452-3981 

6 

4 

913-930 

WOS:000289003800006 

The corrosion inhibition and adsorption processes of 1,2 diaminoanthraquinone (DAQ) on mild steel in HCl was studied at different temperatures (303 - 333
K) by means of weight loss measurement and UV-visible spectrophotometric methods. The results
indicate that the studied compound exhibits good performance as inhibitor for mild steel
corrosion in 1 M HCl. The inhibition efficiency increases with decreasing temperature and
increasing concentration of inhibitor. It has been determined that the adsorption of DAQ on mild
steel obeys the Temkin adsorption isotherm at all studied temperatures with negative values of
Delta G(ads)(o), suggesting a stable and a spontaneous inhibition process. Mechanism of physical
adsorption is proposed from the values of E(a) and Delta G(ads)(o) obtained. The UV-visible
absorption spectra of the solution containing the inhibitor after the immersion of mild steel
specimen indicate the formation of a DAQ-Fe complex. Quantum chemical approach was further used
to calculate some electronic properties of the molecule in order to ascertain any correlation
between the inhibitive effect and molecular structure of DAQ. 

1,2-diaminoanthraquinone (DAQ); adsorption isotherm; Density Functional Theory (DFT); hydrochloric acid; mild steel; corrosion inhibition