| WANG Xia,JIANG Huan,HOU Li,ZHOU Wen-jie,WANG Hui,REN Shuai-fei.Effects of Fe3+ on Corrosion Inhibition and Adsorption Behavior of Double Mannich Bases (DM)[J],47(6):24-30 |
| Effects of Fe3+ on Corrosion Inhibition and Adsorption Behavior of Double Mannich Bases (DM) |
| Received:December 27, 2017 Revised:June 20, 2018 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2018.06.004 |
| KeyWord:Mannich bases adsorption electrochemistry thermodynamics dynamics |
| Author | Institution |
| WANG Xia |
School of Material Science and Engineering, Southwest Petroleum University, Chengdu , China |
| JIANG Huan |
School of Material Science and Engineering, Southwest Petroleum University, Chengdu , China |
| HOU Li |
School of Material Science and Engineering, Southwest Petroleum University, Chengdu , China |
| ZHOU Wen-jie |
School of Material Science and Engineering, Southwest Petroleum University, Chengdu , China |
| WANG Hui |
School of Material Science and Engineering, Southwest Petroleum University, Chengdu , China |
| REN Shuai-fei |
School of Material Science and Engineering, Southwest Petroleum University, Chengdu , China |
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| Abstract: |
| In view of poor service conditions and complicated influence factors of Mannich alkali corrosion inhibitor, the work aims to synthesize the double Mannich base inhibitor (DM) with single Mannich base as intermediate. The influence of Fe3+ on corrosion inhibition of DM was studied in weight loss method and electrochemical method. Adsorption thermodynamics and dynamics of DM on the surface of N80 steel sheet were calculated, and the effects of Fe3+ on adsorption behavior of DM were discussed. Provided with following parameters: temperature as 60 ℃, total volume of corrosive medium as 250 mL, mass fraction of corrosion inhibitor (DM) as 1%, mass fraction of hydrochloric acid as 20% and soaking duration as 4 h, evaluation index for first-grade hydrochloric acid acidizing corrosion inhibitors was met when mass concentration of Fe3+ was less than 900 mg/L and corrosion rate was less than 4 g/(m2•h); and evaluation index for second-grade hydrochloric acid acidizing corrosion inhibitors was met when mass concentration of Fe3+ was more than 900 mg/L and corrosion rate was less than 5 g/(m2•h). ΔGads was －44.86 kJ/mol in 1% DM corrosion inhibition solution, ΔGads was －42.56 kJ/mol when the solution contained Fe3+, and it tended to be －40 kJ/mol compared with solution without Fe3+. Ea value of N80 steel in 20% hydrochloric acid solution was 7.10 kJ/mol, Ea value was 25.45, 23.90 kJ/mol, respectively when 1% DM and 1% DM+600 mg/L Fe3+ was added. ΔEcorr was 50 mV when 1% DM was added, and 30 mV when 1% DM+600 mg/L Fe3+ was added. DM corrosion inhibition efficiency of N80 steel is up to 99.8% in 20% HCl at 60 ℃. The adsorption of DM on N80 steel surface is mixed type adsorption, the adsorption process is spontaneous and exothermic, and adsorption law follows the Langrauir adsorption isotherm. Fe3+ can reduce corrosion inhibition efficiency of DM, but it does not change the type of inhibitor, and it reduces corrosion inhibition efficiency of Fe3+ by destroying chemical adsorption of DM on N80 steel surface. |
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