The corrosion inhibition potential of an antibiotic drug called moxifloxacin for API 5L X-52 steel in 2 M HCl solution was investigated using experimental (gravimetric and electrochemical impedance spectroscopy) and theoretical approaches. Results obtained from gravimetric and electrochemical impedance spectroscopy measurements revealed that moxifloxacin inhibit the corrosion of steel, and recorded instantaneous maximum inhibition efficiency of 88% and 82.7% respectively at 303 ±1 K. Statistical consideration revealed that there was no significant difference between the two methods employed. The adsorption behavior of the inhibitor was best described by the Langmuir adsorption isotherm. Dipole moment calculated from quantum chemical calculation method was found to be in good agreement with those reported for some good corrosion inhibitors. The sites for nucleophilic and electrophilic attacks correspond to the atom N3, C12, C15, C22, C24, C27, O28 and N3, N8, C11, C13, C15, O28 respectively.
In this work, raw red mud was treated with distilled water and its methylene blue (MB) removal efficiency from aqueous solution evaluated and compared to that of raw red mud. The pH, surface charge, particle size distribution, chemical composition, infrared spectrometry and morphology analyses were used to characterize the adsorbents. Batch experiments without agitation and filtration were conducted to determine the influence of contact time, solution pH, temperature, initial dye concentration, adsorbent dose and presence of Cl-, SO42-, HPO42- and HCO3- on dye removal. Distilled water treated red mud (RMW) had improved adsorbent properties than raw red mud (RM). For all the parameters tested, RMW showed higher removals of MB compared to RM. The fitting order for tested isotherm models was: Langmuir > Dubinin–Radushkevich > Freundlich for RMW and Freundlich > Dubinin–Radushkevich > Langmuir for RM. Monolayer adsorption capacities of RMW and RM were found to be 17.123 and 4.221 mg/L respectively. Pseudo-second-order kinetic model suited well than other tested kinetic models. Equilibrium was attained in 24 hours, and the order of shifting of equilibrium to the right as well as the rate of uptake is: MB on RMW > MB on RM. MB removal was found to be more endothermic, more spontaneous and more favourable on RMW than on RM. Desorption experiments using acetone gave good results up to four cycles. These findings revealed that treating red mud with distilled water significantly enhanced its ability to easily remove MB from aqueous solutions.
The inhibitive action of leaves, stem and root extracts of Alternanthera bettzickiana on mild steel corrosion in 5 M H2SO4 solutions was studied using gravimetric technique in the temperature range 30°C to 60°C. Maximum inhibition efficiency (and surface coverage) was obtained at an optimum concentration. However, increase in temperature decreased the inhibition efficiency at the temperature range studied. The experimental data complied with the Langmuir, Freundlich and Temkin adsorption isotherm and the value and sign of the Gibb’s free energy of adsorption obtained suggested that inhibitor molecules have been spontaneously adsorbed onto the mild steel surface through a physical adsorption mechanism. Thermodynamic parameters revealed that the adsorption process is spontaneous.
A carbazole-based monomer, 2-(9-ethylcarbazol-3-yliminomethyl)phenol (SIC), was first synthesized and characterized. It was afterward polymerized by potentiostatic methods. Oxidative polymerization of SIC was carried out in two media. The first one (i.e. Bu4NBF4 (0.1M)/MeCN) gives the poly(2-(9-ethylcarbazol-3-yliminomethyl)phenol). However, the second one (LiClO4/MeCN + 35mM HClO4), leads to another polymer, the poly(2-(9-ethylcarbazol-3-yliminomethyl)cyclohexa-2,5-diene-1,4-dione).These two novel polymers will be abbreviated here after as PSIC and PDIC, respectively. If the formation of PSIC was expected, the formation of PDIC in acidic medium isn’t. It was explained by a hydroxyl function oxidation of SIC. The obtained polymers were then characterized by cyclic voltammetry, electrochemical impedance spectroscopy, XPS, IR and UV-Vis spectroscopies. Furthermore, the corresponding electrochemical and optical bandgap values were calculated in order to get an idea about the conductive properties. The related results show that PDIC and PSIC are good conductive polymers.
This work demonstrates the successful utilization of the Egyptalum company solid waste (slag) for recovery of high-efficiency γ-alumina to be applied as an effective adsorption medium for nitrate uptake from its aqueous solutions. The composite of the sorbent was characterized by XRD, SEM, FTIR, PZC, and BET surface area (SBET). The new sorbent has high surface area, it was found to be 202.39 m2/ g).Also, the adsorptive capacity for nitrate removal was investigated bya series of batch adsorption experiments,and theinfluence of the adsorption controlling parameters such as contact time, adsorbent dosage, pH of the solution, initial concentration of nitrates, and temperature on the removal efficiency of NO3-by alumina from AlSW was evaluated.Furthermore, adsorption isotherms and kinetic studies of the adsorption process were examined. The results of nitrate adsorption were well fitted by pseudo-second order kinetic model, and well explained by Langmuir isotherm model.The maximum adsorption capacity as described from the Langmuir equation was found to be 7.09 mg/ g.