Betti Nadia, Al-Amiery Ahmed A, Al-Azzawi Waleed Khalid
Materials Engineering Department, University of Technology-Iraq, Baghdad 10001, Iraq.
Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi 43000, Malaysia.
Molecules. 2022 Sep 23;27(19):6254. doi: 10.3390/molecules27196254.
A corrosion inhibitor namely N'-(4-hydroxy-3-methoxybenzylidene) nicotinohydrazide was synthesized and the inhibition efficiency of the investigated inhibitor toward the mild steel corrosion in 1 M HCl was studied. The anticorrosion effect has been investigated by weight loss (WL) techniques and electrochemical analysis includes potentiodynamic polarization (PDP) studies and electrochemical impedance spectroscopy (EIS). The current investigation has demonstrated that the tested inhibitor is suitable in corrosive environment and the inhibitive efficacy up to 97% in 1 M HCl. PDP measurements showed that the nicotinohydrazide is a mixed type inhibitor. EIS measurements showed that an increase in the inhibitory concentration leads to an increase in the charge transfer resistance (Rct) and a decrease in the double-layer capacitance (Cdl). Experimental results for the inhibitory performance of WL methods and electrochemical techniques (PDP and EIS) are in good agreement. The tested inhibitor molecules adsorbed on the surface of mild steel in a hydrochloric acid solution followed Langmuir's isothermal adsorption. Quantum chemical parameters based on density function theory (DFT) techniques were conducted on oxygen/nitrogen-bearing heterocyclic molecule employed as a corrosion inhibitor for mild steel in HCl to evaluate the correlation between the inhibitor structure and inhibitory performance. The parameters including the energy gap (Δ), dipole moment (), electronegativity (), electron affinity (), global hardness (), softness (), ionization potential (), the fraction of electrons transferred (Δ), the highest occupied molecular orbital energy (EHOMO), and the lowest unoccupied molecular orbital energy (ELUMO) were also calculated and were in good agreement with the experimental results.
合成了一种缓蚀剂，即N'-(4-羟基-3-甲氧基亚苄基)烟酰肼，并研究了该缓蚀剂对1 M盐酸中低碳钢腐蚀的抑制效率。采用失重(WL)技术研究了其防腐效果，电化学分析包括动电位极化(PDP)研究和电化学阻抗谱(EIS)。目前的研究表明，所测试的缓蚀剂适用于腐蚀环境，在1 M盐酸中的缓蚀效率高达97%。PDP测量表明，烟酰肼是一种混合型缓蚀剂。EIS测量表明，抑制浓度的增加导致电荷转移电阻(Rct)增加，双层电容(Cdl)减小。WL方法和电化学技术(PDP和EIS)的抑制性能实验结果吻合良好。所测试的缓蚀剂分子在盐酸溶液中吸附在低碳钢表面，遵循朗缪尔等温吸附。基于密度泛函理论(DFT)技术对用作盐酸中低碳钢缓蚀剂的含氮/氧杂环分子进行了量子化学参数计算，以评估缓蚀剂结构与缓蚀性能之间的相关性。还计算了包括能隙(Δ)、偶极矩(μ)、电负性(χ)、电子亲和能(A)、全局硬度(η)、软度(S)、电离势(Ip)、转移电子分数(ΔN)、最高占据分子轨道能量(EHOMO)和最低未占据分子轨道能量(ELUMO)等参数，这些参数与实验结果吻合良好。
