Electronic Supplementary Material (ESI) for RSC Advances.
This journal is © The Royal Society of Chemistry 2015
-1
log (i, A cm-2)
-2
-3
1 M HCl
-4
0.00005 M
0.0001 M
-5
0.0005 M
0.001 M
-6
0.005 M
-7
-0.1
-0.3
-0.5
-0.7
-0.9
-1.1
E vs. SCE (V)
Fig. 1. Polarization curves for carbon steel in 1 M HCl in the absence and
presence of different concentrations of inhibitor (AS-Zn) at 25 oC.
Fig. 2. Polarization curves for carbon steel in 1 M HCl in the absence and
presence of different concentrations of inhibitor (AS-Co) at 25 oC.
Fig. 3. Polarization curves for carbon steel in 1 M HCl in the absence and
presence of different concentrations of inhibitor (AS-Cu) at 25 oC.
450
1 M HCl
0.00005 M
Zi ( cm2)
0.0001 M
300
0.0005 M
0.5 Hz
0.001 M
0.005 M
100 kHz
150
85 mHz
0
0
50
100
150
200
250
300
350
400
450
Zr ( cm2)
Fig. 4. Nyquist plots for CS in 1 M HCl in absence and presence of different
concentrations of inhibitor (AS-Zn) at 25 OC
Fig. 5. Nyquist plots for CS in 1 M HCl in absence and presence of different
concentrations of inhibitor (AS-Co) at 25 OC
750
Zi ( cm2 )
600
1 M HCl
0.00005 M
0.0001 M
0.0005 M
0.001 M
0.005 M
0.7 Hz
450
100 k Hz
300
100 m Hz
150
0
0
150
300
Zr(
450
600
750
cm2 )
Fig. 6. Nyquist plots for CS in 1 M HCl in absence and presence of different
concentrations of inhibitor (AS-Cu) at 25 OC
Fig. 7. Electrical equivalent circuit used for modeling the interface Fe/1 M HCl
solution without and with the synthesized surfactant inhibitors.
Fig. 8. Variation of the inhibition efficiency with different concentrations of the
synthesized inhibitors in 1 M HCl at 25 oC.
Fig. 9. Effect of the temperature on the inhibition efficiency was obtained by
weight loss method for carbon steel in 1 M HCl in presence of different
concentrations of inhibitor (AS-Cu).
(a)
(b)
Fig. (10): (a) The EDX spectrum of carbon steel in uninhibited 1.0 M HCl, (b)
in presence of 5x10-3 M of synthesized alginate surfactant (AS-Cu) in 1.0 M
HCl.
(a)
(b)
Fig. 11. SEM image of surface of carbon steel after immersion for 24 h in 1 M HCl at
25 °C in absence (a) and presence of 5 x 10-3 M of AS-Cu(b)