Kapok leaves extract and synergistic iodide as novel effective corrosion inhibitors for Q235 carbon steel in H2SO4 medium

• Published in: Industrial crops and products 2022-04, Vol.178, p.114649, Article 114649
• Main Authors: Wan, Shan, Zhang, Tian, Chen, Huikai, Liao, Bokai, Guo, Xingpeng
• Format: Article
• Language: English
• Subjects: Electrochemical Impedance Spectra; Green corrosion inhibitor; Kapok leaves extracts; Potentiodynamic Polarization Curves
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2022.114649

The kapok leaves were extracted via absolute ethyl alcohol in a Soxhlet extractor. The acquired kapok leaves extract (KLE) and synergistic iodide ions are firstly used as novel environmental-friendly corrosion inhibitors for Q235 carbon steel in 0.5 mol/L H2SO4 solution. The corrosion inhibition performance was researched by electrochemical tests and surface analysis. Results indicated that the KLE and I- inhibitors exhibit a mixed anodic and cathodic inhibition behavior and outstanding inhibition efficiency of 95%. Moreover, it still achieves more than 90% inhibition efficiency after 72 h long-term immersion in sulfuric solution. The adsorption on the carbon steel surface obeys the Langmuir adsorption isotherm model involving physisorption, and the inhibition efficiency decreases with an elevated temperature. The synergistic inhibition mechanism of KLE and I- inhibitors is further revealed. •Kapok leaves extract (KLE) and I- are firstly used as effective corrosion inhibitors.•KLE and I- exhibit more than 90% inhibition efficiency after 72 h immersion.•Synergistic inhibition mechanism is revealed.