Research subject: Synthesis and characterization of a functionalized magnetic nanosorbent (cobalt ferrite–triaminopropyltriethoxysilane–chitosan), optimization and modeling of adsorption conditions, and investigation of the kinetics of monoethylene glycol removal from wastewater.
Research approach: In this research, a functionalized magnetic nanosorbent was used to remove the pollutant monoethylene glycol (MEG) from wastewater. This adsorbent was synthesized by attaching chitosan to the surface of magnetic cobalt ferrite nanoparticles (CoFe2O4) using triaminopropyltriethoxysilane (APTES) as a coupling agent. Chitosan has a high ability to absorb organic pollutants such as monoethylene glycol due to its amino and hydroxyl functional groups. Furthermore, the use of chitosan enhances the surface area and consequently improves the adsorption capacity. The magnetic properties of cobalt ferrite enable easy separation of the adsorbent from the wastewater sample using an external magnetic field. The properties of the synthesized adsorbent were investigated using Fourier transform infrared (FTIR) spectroscopy, vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The optimal adsorption conditions, including pH, contact time, and adsorbent recovery over adsorption–desorption cycles, were also determined.
Main results: The optimal pH value for glycol adsorption from wastewater by the functionalized magnetic nanosorbent was determined to be 6, and the equilibrium contact time was 5 minutes, indicating the high availability of active adsorption sites. Furthermore, the change in adsorption capacity after 10 adsorption–desorption cycles was less than 21%, indicating the high recovery capability and economic feasibility of the adsorbent. Adsorption kinetic data were analyzed using three kinetic models: pseudo-first-order, pseudo-second-order, and intraparticle diffusion. Given the higher correlation coefficient for the pseudo-second-order model (R2 = 0.9951), the adsorption of glycol on the synthesized adsorbent is best described by this model.