Anti-corrosion behaviour of expired tobramycin drug on carbon steel in acidic medium

The anti-corrosion behaviour of the expired Tobramycin (ETo) drug for carbon steel in 2 M HCl solution was investigated by thermometric methods (Thermo), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The results obtained from Thermo, PDP and EIS show that the level of anti-corrosion behaviour is in direct association to the ETo application. The model of adsorption on the carbon steel surface. The PDP technique, indicated by the Tafel plots, demonstrated that the ETo inhibitor acted as a mixed-type inhibitor. The results obtained fromactivation energy, Ea, the quantity of heat adsorbed,Qads, and standard free energy of adsorption, ÄG°ads, show a chemical adsorption mechanism of the ETo inhibitor

Optimization and electrochemical study on the control of mild steel corrosion in hydrochloric acid solution with bitter kola leaf extract as inhibitor

Response surface methodology was applied to predict the optimum control of mild steel corrosion in acid medium with bitter kola leaf extract as inhibitor. The experiment was carried out to investigate the mutual interactions between the considered independent variables and the expected responses. Thermometric, gravimetric, potentiodynamics polarization and electrochemical impedance spectroscopy were used in the corrosion inhibition study. As a supplementary technique, infrared spectroscopy was used to analyze the pure extract and corrosion products and it was observed that some peaks shifted while some disappeared. Inhibition efficiencies of 88.24 %, 86.81 %, 90 %, 89.5 % and 85.3 % were obtained from optimization, thermometric, gravimetric, potentiodynamics polarization and electrochemical impedance spectroscopic techniques, respectively. The bitter kola leaf extract behaved as a mixed-mode inhibitor. Application of response surface methodology in this study was found to be good in predicting the optimum range for controlling of metal corrosion thereby reducing the number of experimental runs.Keywords: Acid, bitter kola leaf, Fourier transform infrared, mild steel, electrochemical impedance spectroscopy, potentio dynamics polarizatio

Machine learning-based performance evaluation and sludge characterization studies of oxidized starch-aluminum electrode assisted by direct current treatment of dye laden wastewater

The performance evaluation, sludge characterization and bi-optimization of treating dye-laden wastewater using oxidized starch-aluminum electrode assisted by direct current was investigated. Variables considered are current density (CD), wastewater pH, oxidized starch (OS) dosage and electrode inter-distance. Electrocoagulation batch reactor incorporated with jar test module was used for the experiment. FTIR, XRD and SEM were conducted to investigate structure, composition and morphology of starch and generated sludge. Sludge settling characteristics and filterability were studied. Response surface methodology (RSM) and artificial neural network (ANN) approach were used to optimize the process. The FTIR peaks revealed alcohol and carboxylic OH groups, while atomic structure indicated partly crystalline pattern. The results showed 96.22 % color removal using 6.6 mA/cm2 CD, 1.0 g/L OS, 4 cm inter-distance, and wastewater pH 4; 100 % COD removal using 4.4 mA/cm2 CD, 1.0 g/L OS, and 3 cm inter-distance at pH 7; and 99.99 % phosphate removal applying 2.2 mA/cm2 CD, 1.0 g/L OS, and 4 cm between electrode at pH 7. The sludge settling indicated lag, hindered, transition and compression zones, while sludge volume indices were less than 80 mg/g. The ANOVA revealed significant models with Prob > F  0.99 for all the response variables, indicated better optimization approach. From the forgoing, the use of combined technology; electro and chemical coagulation is beneficial toward achieving better result in the treatment of dye laden wastewater