Ion-exchange kinetics and thermal decomposition characteristics of Fe 2+-exchanged alginic acid membrane for the formation of iron oxide nanoparticles

The ion-exchange kinetics of Fe2+ cations in aqueous solution with H+ from alginic acid have been analyzed in this study as a function of contact time lengths using inductively coupled plasma-atomic emission spectrometry analysis. The kinetic parameters have been evaluated using pseudo 1st or 2nd order models, and a consistent ion-exchange mechanism is suggested. Furthermore, an insight into the calcination of Fe2+ ion-exchanged alginic acid process has been obtained by using simultaneous thermo-gravimetric analysis coupled with differential scanning calorimetry and high temperature X-ray diffraction. © 2014 Springer Science+Business Media New York

Inhibition of mild steel corrosion in HCI solution using chitosan

The efficiency of chitosan (a naturally occurring polymer) as a corrosion inhibitor for mild steel in 0.1 M HCl, was investigated by gravimetric, electrochemical and spectroscopic measurements (SEM observations and UV-visible analysis). The polymer was found to inhibit corrosion even at a very low concentration. Inhibition efficiency increases with a rise in temperature up to 96 % at 60°C and then drops to 93% at 70°C, while it slightly increases with an increase in chitosan concentration. Polarization curves indicate that chitosan functions as a mixed inhibitor, affecting both cathodic and anodic corrosion reactions. Impedance results indicate that chitosan was adsorbed on the metal/solution interface. Adsorption of chitosan at the mild steel surface is found to be in agreement with Langmuir adsorption isotherm model. Chemical adsorption is the proposed mechanism for corrosion inhibition considering the trend of protection efficiency with temperature. Calculated kinetic and thermodynamic parameters corroborate the proposed mechanism.Fil: Umoren, Saviour E.. University of Uyo. Faculty of Science; Nigeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Banera, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Alonso Garcia, Teodoro. Biosurfaces Unit, Cic BIOMAGUNE; EspañaFil: Gervasi, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; ArgentinaFil: Mirifico, Maria Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de La Plata; Argentin