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YILDIZ, MESUT/0000-0001-6964-6705; KAYA, ERTUGRUL/0000-0003-1579-6411; Gerengi, Husnu/0000-0002-9663-4264; Solomon, Moses/0000-0002-3251-8846; Umoren, Saviour/0000-0002-8564-4897 WOS: 000425767400010 The efficacy of 1-butyl-1-methylpiperidinium tetrafluoroborate (BMPTFB) in retarding St37 steel corrosion in HCl environment has been examined using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), dynamic-EIS (DEIS), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) techniques. Results from all applied methods reveal that BMPTFB is effective in suppressing St37 dissolution in the studied corrosive medium. Inhibition efficiency of 88% has been achieved by 4mM BMPTFB. From DEIS results, BMPTFB is found to perform better as corrosion inhibitor at longer immersion time. The charge transfer resistance of the metal is raised in the presence of 4mM BMPTFB from 378 to 744 cm(2) at 1h and further increased to 867 cm(2) at 4h. BMPTFB, according to PDP result behaves as mixed-type corrosion inhibitor. Corrosion inhibition by BMPTFB is via adsorption which can best be explained using El-Awady kinetic/thermodynamic adsorption isotherm. K-ads and values indicate that physisorption is the mechanism of adsorption of BMPTFB molecules onto St37 surface. The presence of BMPTFB molecules on St37 surface has been verified by SEM and FTIR. Duzce University Research Council for Science and Technology (BAP) [2016.06.05.492] The authors acknowledge the following: (i) Dr Kazimierz Darowicki and Pawel Slepski for providing the DEIS software and (ii) Duzce University Research Council for Science and Technology (BAP) for the financial support (Project No. 2016.06.05.492).

Humic acids (HAs) extracted from cow, goat, and poultry dung were studied. Extraction was performed by treating the source materials with acid hydrolysis using hydrochloric acid (HCl) before alkaline extraction with sodium hydroxide (NaOH). Yields of 3.33, 2.67, and 1.28% dry weight were obtained from cow, goat, and poultry dung respectively. The extracted humic acids were characterized using Fourier transform-infrared (FT-IR) and ultraviolet-visible (UV-vis) spectroscopy techniques. The results obtained were in good agreement with commercial HA (Sigma-Aldrich). The humic acid extracted from cow dung was used to evaluate its corrosion inhibition potential for alkaline-induced corrosion of 3SR aluminum alloy using weight loss and electrochemical (potentiodynamic polarization) techniques at 30°–60°C. Results obtained show that the humic acid functions as an excellent corrosion inhibitor for aluminum alloy in 0.1 M NaOH solution. Corrosion inhibition efficiency increased with increase in humic acid concentra...

The adsorption of fluconazole (FLU) on aluminum surface from 0.1 M HCl solution was studied using chemical technique at 30°–50°C. The values for free energy of adsorption, , were calculated at each surface coverage, θ, of the studied compound by applying the mathematical model of the Bockris-Swinkels adsorption isotherm. The phenomenon of physical adsorption is proposed from the value of Gibbs free energy, , obtained from the Bockris-Swinkels adsorption equation and the mean adsorption energy, E, using the adsorption isotherm model of Dubinin-Radushkevich (D-R). A zero-order kinetics relationship with respect to aluminum was obtained with and without FLU from the kinetic treatment of the data.

The corrosion inhibitive effects of Pachylobus edulis exudate gum for mild steel in 2 M H2SO4 and influence of potassium halide additives on the inhibition efficiency were investigated using hydrogen evolution and thermometric methods at 30°–60°C. Inhibition efficiency was determined by comparing the corrosion rates in the absence and presence of additives. The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition. It was found that the exudate gum acts as an inhibitor for acid-induced corrosion of mild steel. Inhibition efficiency (%I) of the exudate gum increased with an increase in concentration of the exudate gum and synergistically increased on addition of potassium halides but decreased with increase in temperature. Inhibitor adsorption characteristics were approximated by Temkin adsorption isotherm at all the concentrations and temperatures studied. The phenomenon of physical adsorption is proposed from the activation parameters obtained.

A biodegradable polymer mud was prepared using Millet starch pre-gelatinized in the absence of a solvent. The filtration and rheological properties of the mud were studied at 25°–200°C temperature range and at 0.01–0.05 g/mL concentration of starch using filter loss and viscometric methods respectively. Experimental results showed that the new mud has better filtration control behavior and thermal stability at all the temperatures than widely used mud prepared with hydroxy propyl–modified starch. The mud displayed thermal degradation at 200°C. The values of flow index were found to be less than 1.0, showing non-Newtonian and pseudoplastic flow behavior of the mud. Shear stress and yield stress increase with increase in concentration. Viscosity decreases with increasing shear rate, showing shear thinning behavior of the mud. The polymer mud obeyed Henri Darcy and API models for static filtration as well as power law and Herschel-Bulkley models for fluid rheology. The new mud is purer and more suitable for ...