Table 2 Green corrosion inhibitors for preventing CO2 corrosion sorted based on the lowest corrosion rate obtained from polarisation parameters.
From: A review of plant extracts as green corrosion inhibitors for CO2 corrosion of carbon steel
Plant extract | Steel specimen | Inhibitor concentration (at max. IE%) | Testing temperature (°C) | Uninhibited corrosion rate (mm y−1) | Inhibited corrosion rate (mm y−1) | Testing solution |
|---|---|---|---|---|---|---|
Cashew nut shell liquid | SAE 1008 CS | 1200 ppm | 30 | 0.299 | 0.002 | CO2-saturated 3.0% NaCl (pH 6) |
Kuding | J55 | 4 v/v % (40,000 ppm) | 25 | 0.418 | 0.014 | CO2-saturated 3.5% NaCl |
Olive leaf | N80 | 300 ppm | 25 | 1.297 | 0.019 | CO2-saturated 3.0% NaCl + 0.01% NaHCO3 + 0.01% CaCO3 |
Cashew nut shell liquid | SAE 1008 CS | 300 ppm | 30 | 0.402 | 0.030 | CO2-saturated 3.0% NaCl (pH 6) |
Jatropha curcas leaf extract | API 5L-X65 | 400 ppm | 25 | 1.205 | 0.040 | CO2-saturated 3.5% NaCl (pH 4.7) |
Olive leaf | N80 | 300 ppm | 65 | 1.262 | 0.064 | CO2-saturated 3.0% NaCl + 0.01% HaHCO3 + 0.01% CaCO3 |
Jatropha curcas leaf extract | X65 MS | 400 ppm | 50 | 2.449 | 0.095 | CO2-saturated 3.5% NaCl (pH 4.7) |
Sida acuta | API 5L-X65 | 400 ppm | 25 | 1.162 | 0.112 | CO2-saturated 3.5% NaCl (pH 4.5) |
Cashew nut shell liquid | SAE 1008 CS | 1200 ppm | 30 | 0.640 | 0.113 | CO2-saturated 3.0% NaCl (pH 4) |
Coptis chinensis | L360 CS | 50 ppm (+10 ppm Thiourea) | 60 | 2.661 | 0.113 | CO2-saturated 3.0% NaCl |
Liquorice | API 5L Grade B | 3000 ppm | 25 | 0.639 | 0.115 | CO2-saturated 3.5% NaCl + 0.3% CaCl2 + 0.2% MgCl2.6H2O (~pH 4.0) |
Tobacco leaf | AISI 1045 | 132.5 ppm | – | 0.330 | 0.121 | CO2-saturated 3.5% NaCl(pH 7) |
Pomelo | N80 | 400 ppm | 30 | 1.845 | 0.124 | CO2-saturated 3.5% NaCl (pH 4.2) |
Calotropis procera | MS | 200 ppm | 25 | 2.921 | 0.230 | CO2-saturated 3.5% NaCl |
Tobacco leaf | AISI 1045 | 265 ppm | – | 1.774 | 0.244 | CO2-saturated 3.5% NaCl (pH 4) |
Corn oil-derived diethanolamine sulfated fatty acid | C1018 MS | 100 ppm | 50 | 24.401 | 0.244 | CO2-saturated 1% NaCl (pH 5.60) |
Berberine | L360 CS | 100 ppm (+10 ppm Thiourea) | 60 | 2.661 | 0.282 | CO2-saturated 3.0% NaCl |
Calotropis procera | MS | 200 ppm | 40 | 4.463 | 0.325 | CO2-saturated 3.5% NaCl |
Calotropis procera | MS | 200 ppm | 50 | 4.463 | 0.325 | CO2-saturated 3.5% NaCl |
Jatropha curcas oil | A106 CS | 150 ppm | Room temperature | 2.24a | 0.39a | CO2-saturated 3.0% NaCl |
Dimocarpus longan | API 5L | 400 ppm | Ambient temperature | 0.923 | 0.454 | CO2-saturated 1.3% NaCl + 0.09% HaHCO3 + 0.74% Na2SO4 |
Calotropis procera | MS | 200 ppm | 70 | 5.638 | 2.944 | CO2-saturated 3.5% NaCl |
