Sequestration of cadmium ions from aqueous phase using magnetic chitosan composite

Abstract

Present communication reports on the synthesis, characterization and application of Fe3O4-chitosan composite (MCC). The magnetic chitosan composite are crafted by mixing Fe3O4 nanoparticles solution to chitosan solution. Fe3O4 nanoparticles have been synthesized by co-precipitation method. The synthesized composite have been extensively characterized using various techniques such as FTIR, TEM, XRD and BET analysis. The surface area analysis suggested that the materials synthesized is mesoporous in nature. Incorporation of chitosan crosslinked actively with Fe3O4 nanoparticles that results in reduction of surface area and narrower pore size distribution of the composite than pure Fe3O4 nanoparticles. TEM study demonstrated that Fe3O4 nanoparticles were found in the range of 20–25 nm. The synthesized composite is able to capture more than 89% Cd(II) from synthetic Cd(II) solution within 80 min of contact time. The adsorption equilibrium data better conformed with the Langmuir isotherm. The maximum capacity determined from Langmuir isotherm was 149.92 mg/g at 323 K. Adsorption kinetics of cadmium on MCC could be well analyzed with pseudo-second-order kinetic model. Thermodynamics investigation reveals that with the increase of solution temperature 303 K, 313 K and 323 K the ΔGo values decreases correspondingly to −87.76, −90.36 and -93.36 KJ/mol, suggesting endothermic nature of the adsorption process. The adsorbent could be successfully reused for more than five cycles. Thus, MCC can be serves as a reliable and sustainable material for efficient sequestration of Cd(II) species from aqueous environment.