The Pharmaceutical and Chemical Journal, 2016, 3(1):109-119 The Pharmaceutical and Chemical Journal 109 Available online www.tpcj.org Research Article ISSN: 2349-7092 CODEN(USA): PCJHBA Adsorption and Inhibitive Properties of Januvia for the Corrosion of Zn in 0.1 M HCl AM Kolo 1* , UM Sani 2 , IU Kutama 3 , Umar Usman 4 1 Department of Chemistry, Corrosion Protection and Materials Science Laboratory, AbubakarTafawa Balewa University, Bauchi, Nigeria 2 Department of Chemistry, NigeriaPolice Academy Wudil, Kano State, Nigeria 3 Department of Chemistry, Kano State University of Science and Technology Wudil Kano State 4 Department of Physical Sciences, College of Arts, Science and Remedial Studies, Kano, Nigeria Abstract The inhibitive and adsorptive characteristics of Januviafor the corrosion of zinc in HCl solutions have been studied using weight loss and gasometric methods of monitoring corrosion. The results obtained reveal that various concentrations of Januvia inhibited the corrosion of zinc in HCl between the temperature ranges of 303- 333K. The inhibition efficiency of the inhibitor was found to decrease with temperature.Kinetic consideration reveals that the inhibited and uninhibited corrosion of zinc in the acid proceeded via first order kinetics with half-life values for the inhibited reactions being higher than values for the uninhibited systems. Thermodynamics consideration also reveals that this inhibitor is adsorbed on zinc surface by spontaneous physical adsorption mechanism. Values of free energy were lower than the threshold value of 40 kJ/mol. Also Temkin adsorption isotherms best described the adsorption characteristics of the inhibitor. Keywords acid corrosion, weight loss, drugs, zinc, HCl Introduction Almost all metals are prone to corrosion and the level of corrosion attack depends on the type of metal and the condition of the environment. Several measures have been adopted to protect metals against corrosion including cathodic/anodic protection, greasing and galvanizing. However, the use of inhibitors has proved to be one of the best options. Corrosion inhibitors are substances, which will slow down the rate of corrosion when added in minute quantities [1]. Due to the toxicity of widely used corrosion inhibitors and the ever tightening environmental regulations surrounding their use and disposal, there is great interest in replacing harmful inhibitors with effective non-hazardous alternatives. Drugs (chemical medicines) seem to be ideal candidates to replace traditional toxic corrosion inhibitors because of their natural origin, as well as their non-toxic characteristics and negligible negative impacts on the aquatic environment [2-5], Several studies have been carried out and reported for the use of drugs as corrosion inhibitors. For example Cefuroxime axetil (CA) a pro- drug was tested as corrosion inhibitor for aluminum in hydrochloric acid solution by Ameh and Sani [6] using thermometric, gasometric weight loss and scanning electron microscope (SEM) techniques. Results obtained showed that this compound has good inhibiting properties for aluminum corrosion in acidic medium, with inhibition efficiencies values reaching 89.87 % at 0.5 g / L. The adsorption of the inhibitor was also found to be spontaneous, exothermic and best fitted the Langmuir adsorption model. Shukla and Quraishi [7] studied the inhibition efficiency of cefalexin drug for the corrosion mild steel in 1 MH Clusing electrochemical and weight loss measurements. The physical adsorption of the protonated cefalexin molecules on mild steel was suggested due the electrostatic attractions. The inhibiting effect of streptoquin and septazole towards the corrosion of the copper in 0.1M of HCl solution was also studied by Fouda and Gadow [8] using potentiodynamic polarization measurements, electrochemical