Thiamine hydrochloride (vitamin B1) has been tested as a potential inhibitor for aluminium corrosion in 1.0 M hydrochloric acid solution, using mass loss technique and DFT studies. These studies were performed in the concentration range of 0.13 mM to 0.53 mM and the temperature range of 303 K to 323 K. The experimental results show that the inhibition efficiency is concentration and temperature dependent. Experimental data were used to fit adsorption isotherms including Langmuir, El-Awady, Freundlich and Temkin. Though the Langmuir model was the appropriate isotherm, it could not be applied rigorously. Furthermore, the Adejo-Ekwenchi isotherm was used to characterize the type of adsorption. The thermodynamic adsorption and activation functions were determined and analysed. They indicate a spontaneous adsorption process and both physisorption and chemisorption processes. Density functional theory (DFT) calculations were performed and discussed. They reveal good correlations between experimental and theoretical results
