Sorption behavior and release kinetics of iron (II) ions by oleoyl chitosan polymeric nanoparticles

This work describes an evaluation of a self-emulsified polymeric nanoparticle system using low molecular weight oleoyl chitosan derivative and its ability to adsorb iron (II). Iron (II) sulfate was used as a source of iron (II). The system suitability for enhancing iron (II) sorption within the micellar structure was illustrated and compared with parent chitosan. Physico-chemical properties and sorption mechanisms of iron (II) ions on oleoyl chitosan were evaluated. Oleoyl chitosan exhibited higher wettability as indicated by low values of contact angle measurements and a decrease in surface tension with an increase in viscosity compared to parent chitosan. It was found that oleoyl chitosan resulted in a unique aggregation pattern, where at least two critical aggregation concentrations were detected. The binding of iron (II) to oeloyl chitosan was best fit to Langmuir equation, while chitosan nanoparticles showed Freundlich behavior. Results further confirmed the effectiveness of oleoyl chitosan to act as a promising iron (II) carrier system as indicated by the higher sorption percentage. Moreover, the release kinetics of iron (II) ions out of oleoyl chitosan at different pH conditions was investigated and it was best described by Hill and Michaelis-Menten equations.