Fe3O4-chitosan nanocomposite as a magnetic biosorbent for removal of nickel and cobalt heavy metals from polluted water

Recently, natural polymers like chitosan have gained attention as promising adsorbents for water treatment. By combining chitosan with magnetic nanoparticles, their adsorption capabilities can be enhanced. In this study, chitosan-magnetite nanocomposite (CMNC) was synthesized via coprecipitation method to remove nickel and cobalt from aqueous solutions. The physicochemical properties of the synthesized CMNC were investigated by various techniques, including FESEM, TEM, XPS, FTIR, XRD, and VSM. The electron microscopy results confirmed the uniform dispersion of magnetite nanoparticles within CMNC nanocomposites, while VSM confirmed their significant magnetic properties. The adsorption experiments showed that at optimal conditions (pH = 6, contact time = 2 h, adsorbent dosage = 2 g/l), CMNC has high adsorption capacities of 30.03 mg/g for Ni2+ and 53.19 mg/g for Co2+. Furthermore, the adsorption data fitted best with the Langmuir isotherm, show that the active sites on CMNC are energetically homogenous. According to kinetic analysis, the experimental data were in good agreement with both pseudo-second-order and intra-particle diffusion models, which suggest that chemical sorption, along with mass transfer steps, influence the overall adsorption process. Finally, investigating the thermodynamic parameters (& UDelta;Gads, & UDelta;Hads, & UDelta;Sads) showed that the adsorption process on CMNC was endo-thermic and spontaneous, with stronger interactions observed between CMNC and Co2+ compared to Ni2+.

Automated summary

Recently, chitosan-magnetite nanocomposite (CMNC) has been synthesized as a promising adsorbent for water treatment, with enhanced adsorption capabilities for nickel and cobalt. The physicochemical properties of CMNC were investigated, confirming the uniform dispersion of magnetite nanoparticles and its significant magnetic properties. Adsorption experiments showed high capacities for Ni2+ and Co2+, and the Langmuir isotherm was found to best fit the adsorption data, indicating energetically homogenous active sites on CMNC. Kinetic analysis suggested that chemical sorption and mass transfer steps both influence the adsorption process. Thermodynamic parameters showed that the adsorption process on CMNC was endo-thermic and spontaneous, with stronger interactions between CMNC and Co2+.