Kamel Medhat M, Abdou Safaa N, Anwar Zainab M, Sherif Magdy A, Mostafa Nasser Y
Department of Chemistry, Faculty of Science, Suez Canal University Ismailia 41522 Egypt
Department of Chemistry, Khurmah University College, Taif University Taif Saudi Arabia.
RSC Adv. 2025 Mar 19;15(11):8506-8522. doi: 10.1039/d5ra00650c. eCollection 2025 Mar 17.
Drug disposal costs and drug-related environmental pollution could be reduced by reusing expired drugs. A well-known cephalosporin antibiotic that was listed as an essential medication by the World Health Organization is Ceftazidime. In this study, the corrosion mitigation properties of the expired Ceftazidime (CDZ) drug for zinc corrosion in 1 mol per L HCl solution were examined by weight loss (WL), frequency modulation (EFM), potentiodynamic polarization (PDP), and impedance spectroscopy (EIS) techniques. Theoretical calculations were carried out by Density Functional Tight Binding (DFTB) and Monte Carlo (MC) simulations. Furthermore, scanning electron microscopy (SEM) and energy dispersion X-rays (EDX) were used for examining the appearance and structure of the corroded zinc surface, respectively. For a CDZ concentration of 300 ppm, EFM techniques have shown an inhibitive efficiency (IE) of 70.3% at 298 K. The IE increased as the drug concentration increased from 50 to 300 ppm, whereas it reduced as the temperature increased. The inhibition effect ceased to improve at concentrations greater than 300 ppm. A mixed form of adsorption (physisorption and chemisorption) was suggested for inhibition. The adsorption process followed the Temkin model. The spontaneous character and exothermicity of the adsorption process were demonstrated by the and magnitudes. The PDP study demonstrated that CDZ was a mixed-type inhibitor as it retards both the cathodic and anodic reactions. According to EFM results, increasing the concentration of CDZ from 50 to 300 ppm reduces the corrosion current density from 163.5 to 78.7 μA cm. SEM and EDX examinations revealed the adsorption of CDZ drug at the zinc surface. The DFTB and MC simulations revealed that the CDZ drug bonds to the zinc surface the heteroatoms' lone pair of electrons and the pyridinium ring's π-electrons. The adsorption energy of the drug on the Zn surface was found to be -77.41 kJ mol.
通过再利用过期药物，可以降低药物处理成本和与药物相关的环境污染。头孢他啶是一种著名的头孢菌素抗生素，被世界卫生组织列为基本药物。在本研究中，采用失重法（WL）、调频法（EFM）、动电位极化法（PDP）和阻抗谱法（EIS）研究了过期头孢他啶（CDZ）药物在1 mol/L HCl溶液中对锌腐蚀的缓蚀性能。通过密度泛函紧束缚（DFTB）和蒙特卡罗（MC）模拟进行了理论计算。此外，分别使用扫描电子显微镜（SEM）和能量色散X射线（EDX）来检查腐蚀锌表面的外观和结构。对于300 ppm的CDZ浓度，EFM技术在298 K时显示出70.3%的缓蚀效率（IE）。随着药物浓度从50 ppm增加到300 ppm，IE增加，而随着温度升高，IE降低。当浓度大于300 ppm时，抑制效果不再改善。建议采用混合吸附形式（物理吸附和化学吸附）进行抑制。吸附过程遵循Temkin模型。吸附过程的自发性和放热性通过 和 大小得到证明。PDP研究表明，CDZ是一种混合型抑制剂，因为它同时抑制阴极和阳极反应。根据EFM结果，将CDZ浓度从50 ppm增加到300 ppm可使腐蚀电流密度从163.5 μA/cm降低到78.7 μA/cm。SEM和EDX检查揭示了CDZ药物在锌表面的吸附。DFTB和MC模拟表明，CDZ药物通过杂原子的孤对电子和吡啶环的π电子与锌表面结合。发现该药物在锌表面的吸附能为-77.41 kJ/mol。
