Chemical and Electrochemical Studies on Expired Lioresal Drugs as Corrosion Inhibitors for Carbon Steel in Sulfuric Acid

Abstract

Lioresal is a muscle relaxer and an antispasmodic agent, known as Lioresal. The active ingredient is β-(Aminomethyl)-p-chlorohydrocinnamic acid, a racemic mixture of the R,(-) and S, (+) isomers. It affects directly the spinal cord with adverse effects including drowsiness, dizziness, weakness, fatigue, headache, trouble sleeping, nausea and vomiting, urinary retention, or constipation. Therefore, the accumulation of expired or unused Lioresal in our home is so dangerous and harmful for our children. The present work introduces an idea for using expired Lioresal as a corrosion inhibitor for steel in 1.0 M H2SO4. The effect of both concentration and temperature were studied. The inhibition efficiency was found to increase with concentration and decreased with rising temperature. Chemical, electrochemical, and analytical techniques, namely, gravimetric, thermometric, gasometric, acidimetric, AAS, and potentiodynamic polarization were used to evaluate the inhibition action of the expired Lioresal drugs. The inhibition performance is due to the adsorption and adhesion of drugs constituent molecules on the steel surface. The adsorption was found to obey Langmuir isotherm. The surface area available for the anodic dissolution of iron and cathodic hydrogen evolution process diminishes without changing the reaction mechanism. The values of Ecorr. readings slowly decrease to negative values, showing that these inhibitors are mixed-type inhibitors mainly cathodic inhibitors. The data obtained from different techniques are in good agreement with each other. Electrochemical and analytical Techniques are efficient and accurate in the determination of the corrosion rate and inhibition performance of expired drugs in an aqueous medium.

Manufacturing of Corrosion Inhibitors and Flow Improvers from Recycling of Waste at Hail City, Saudi Arabia: Physicochemical and Electrochemical Studies on Steel in Petroleum Industries

“…Weight loss data was employed. According to the following equation, − the Langmuir adsorption isotherm best fits the results where K and C are the equilibrium constant of the adsorption process and the drug concentration, respectively. − The large values of the calculated (K ads .) indicate the stronger adsorption of the inhibitor on the metal surface. − …”

“…The absence of a positive result for Δ G ° ads denotes spontaneous inhibitor molecule adsorption on the metal surface. − The obtained value, on the other hand, is lower than the −40 kJ/mol threshold value needed for chemical adsorption, which suggests that the process of adsorption is physical. The absence of a positive result for Δ G ° ads denotes spontaneous drug molecule adsorption on the metal surface. − It is widely acknowledged that the investigated compound PETAA inhibitor derived from PET plastic waste inhibits corrosion by adsorption and adhering at the metal/solution contact. Additionally, it has thought that the development of a solid organic molecule complex with the metal atom has drawn a lot of interest. − …”

“…The absence of a positive result for Δ G ° ads denotes spontaneous drug molecule adsorption on the metal surface. − It is widely acknowledged that the investigated compound PETAA inhibitor derived from PET plastic waste inhibits corrosion by adsorption and adhering at the metal/solution contact. Additionally, it has thought that the development of a solid organic molecule complex with the metal atom has drawn a lot of interest. − …”

“…Adsorption of the inhibitor molecules at the metal/solution interface is the first step in the inhibitory mechanism, which controls corrosion. − When organic molecules are inhibited, four different forms of adsorption may occur at the metal/solution contact: − The attraction between charged molecules and metals through electrostatic forces The interaction of the metal with the unshared electron pairs in the molecule. Interactions of Pi electrons with metal, and A combination of the first three possibilities. …”

Synthesis, characterization, and evaluation of polymeric surfactants derived from PET plastic waste as green corrosion inhibitor of steel surfaces in marine environment for heavy industry

“…The inhibitory efficiency was calculated using charge-transfer resistance, which is represented as R p in the Nyquist plots' impedance data. 65–71…”