Experimental and Theoretical Investigations on Copper Corrosion Inhibition by Cefixime Drug in 1M HNO3 Solution

Nagnonta Hippolyte Coulibaly,Ollo Kambiré,Albert Trokourey,N’guessan Yao Silvère Diki

doi:10.4236/msce.2021.95002

Abstract

Cefixime, a third-generation semi-synthetic cephalosporin antibiotic was used as a copper corrosion inhibitor in 1M HNO3 solution. The study was conducted through the weight loss technique at 298 - 318 K and theoretical studies based on quantum chemistry. The studied drug inhibited the corrosion of copper in 1M HNO3 over the cefixime concentration range (0.02 - 2 mM). The inhibition efficiency increased with an increase in the inhibitor concentration to reach 91.07% at 2 mM, but decreased with an increase in temperature. The thermodynamic functions related to the adsorption of cefixime on the copper surface and that of the metal dissolution were computed and analyzed. The results point out spontaneous adsorption, mainly through a physisorption mechanism following Langmuir adsorption isotherm model and an endothermic dissolution process. Quantum chemical calculations were also performed at B3LYP level with 6-31G (d, p) basis set and lead to molecular descriptors such as EHOMO (energy of the highest occupied molecular orbital), ELUMO (energy of the lowest unoccupied molecular orbital), ΔE (energy gap) and μ (dipole moment). The global reactivity descriptors such as χ (electronegativity), χ (global hardness), S (global softness), and ω (electrophilicity index) were derived using Koopman’s theorem and analyzed. The local reactivity parameters, including Fukui functions and dual descriptors were determined and discussed. Experimental and theoretical results were found to be in good agreement.

Highlights

Copper [1] [2] is one of the most used metals for several engineering and industrial applications including electricity and electronics, communications, pipelines for domestic and industrial water utilities, fabrication of heat exchanger tubes, and cooling water systems due to its excellent properties
Quantum chemical calculations were performed at B3LYP level with 6-31G (d, p) basis set and lead to molecular descriptors such as EHOMO, ELUMO, ΔE and μ
The choice of some drugs used as corrosion inhibitors is based on the following justifications: 1) drugs are mainly soluble in aqueous media; 2) drug molecules contain oxygen, nitrogen and sulphur as active centers; 3) drugs are reportedly environmentally friendly and important in biological reactions; and 4) drugs including β-lactam antibiotics, quinolones, antifungal, and cephalosporins can be produced and purified [11] [12] [13] [14]

Summary

Introduction

Copper [1] [2] is one of the most used metals for several engineering and industrial applications including electricity and electronics, communications, pipelines for domestic and industrial water utilities, fabrication of heat exchanger tubes, and cooling water systems due to its excellent properties. The use of some organic chemical inhibitors is limited by diverse reasons especially their costly synthesis, poor biodegradability, toxic and hazardous for human beings and the environment as well For this purpose, natural products of plant origin or drugs are a better choice due to the fact that they are environmentally benign and contain incredibly rich sources of naturally synthesized organic compounds among which most of them are known to have inhibitive action. The aim of the present paper is to highlight the relationship between the calculated quantum chemical parameters and the experimentally determined inhibition efficiency of cefixime drug (Scheme 1) against copper corrosion in 1M HNO3 medium This can be achieved by computing the most relevant electronic properties of the studied compound including EHOMO, ELUMO, energy Gap (ΔE), dipole moment (μ), electronegativity (χ), global hardness (η), fraction of electrons transferred (ΔN) and charges (δ) on atoms

Objectives

Results

Conclusion