Egyptian Petroleum Research Institute (EPRI), Nasr City, 11727, Cairo, Egypt.
Physics Department, Faculty of Science, Ha'il University, Hail, Saudi Arabia.
Int J Biol Macromol. 2024 Nov;279(Pt 4):135408. doi: 10.1016/j.ijbiomac.2024.135408. Epub 2024 Sep 10.
The industrial and medical sectors have a great interest in chitosan due to its unique properties, such as abundance, renewability, non-toxicity, antibacterial activity, biodegradability, and polyfunctionality. In this work, two modified chitosan Schiff bases (ChSB-1 and ChSB-2) were made using condensation methods, and their potential as corrosion inhibitor for carbon steel in 1 M HCl was investigated using chemical and electrochemical techniques. The ChSB-1 and ChSB-2 inhibitors exhibited remarkable inhibitory performance, as evidenced by the mass loss data, which showed 89.3 % and 91.5 % efficacy at 1 mM concentration, respectively. Because of the electron-donor substituent of methoxy (-OCH), ChSB-2's active sites have more delocalized electrons than ChSB-1's. The PDP results showed that both ChSB-1 and ChSB-2 inhibitors have anti-corrosion characteristics because heteroatoms caused a protective layer to develop that functioned as mixed-typed inhibitors. The calculated adsorption-free energy ∆G for ChSB-1 and ChSB-2, respectively, was found -36.1 and - 37.1 kJ mol. The ChSB-1 and ChSB-2 inhibitors adsorb on carbon steel in acidic conditions through physisorption and chemisorption interactions, and their adsorption is in line with the Langmuir adsorption model. Inhibited and uninhibited metallic surfaces were subjected to surface morphological assessments using contact angle (CA), the scanning electron microscopy and the energy dispersive X-ray (SEM/EDX) analysis. The DMol part of Materials Studio 7.0 software was used to perform the quantum chemical calculations based on DFT to visualize the structural features. Studies from quantum chemistry suggest the possibility of surface interaction between the unoccupied orbitals of the metal surface and the inhibitors ChSB-1, ChSB-2, ChSB-1H, and ChSB-2H. The results clearly show that the two inhibitors work well as environmentally friendly carbon steel corrosion inhibitors in acidic medium. This could be advantageous for industrial procedures such as pickling, cleaning, acidizing oil drilling in oil wells, and using citrus to de-sediment boilers.
壳聚糖因其丰富、可再生、无毒、抗菌活性、生物降解性和多功能性等独特性质，引起了工业和医疗领域的极大兴趣。在这项工作中，使用缩合方法制备了两种改性壳聚糖席夫碱（ChSB-1 和 ChSB-2），并使用化学和电化学技术研究了它们在 1M HCl 中作为碳钢缓蚀剂的潜力。ChSB-1 和 ChSB-2 抑制剂表现出显著的抑制性能，质量损失数据表明，在 1mM 浓度下分别具有 89.3%和 91.5%的效率。由于甲氧基（-OCH）的供电子取代基，ChSB-2 的活性位点比 ChSB-1 的活性位点具有更多的离域电子。PDP 结果表明，ChSB-1 和 ChSB-2 抑制剂均具有防腐特性，因为杂原子形成了一层保护层，起到了混合型抑制剂的作用。计算得出 ChSB-1 和 ChSB-2 的吸附自由能∆G 分别为-36.1kJ/mol 和-37.1kJ/mol。ChSB-1 和 ChSB-2 抑制剂在酸性条件下通过物理吸附和化学吸附相互作用吸附在碳钢上，其吸附符合 Langmuir 吸附模型。使用接触角（CA）、扫描电子显微镜和能量色散 X 射线（SEM/EDX）分析对受抑制和未受抑制的金属表面进行表面形貌评估。Materials Studio 7.0 软件的 DMol 部分用于根据 DFT 执行量子化学计算，以可视化结构特征。量子化学研究表明，金属表面的未占据轨道和抑制剂 ChSB-1、ChSB-2、ChSB-1H 和 ChSB-2H 之间可能存在表面相互作用。结果清楚地表明，这两种抑制剂在酸性介质中作为环保型碳钢缓蚀剂效果良好。这对于工业过程可能是有利的，例如酸洗、清洁、酸化油井、使用柑橘类水果去除锅炉中的沉积物。
