Green synthesis of Fe3O4 nanoparticles loaded sawdust carbon for cadmium (II) removal from water: Regeneration and mechanism.

This study focused on the synthesis and characterization of novel magnetic iron oxide nanoparticles loaded sawdust carbon (Fe3O4/SC) and EDTA modified Fe3O4/SC (EDTA@Fe3O4/SC) nanocomposites (ncs) by low cost biogenic green synthesis approach and their application for Cd (II) removal from aqueous medium in batch mode. In isotherm studies, Langmuir and Freundlich models are best fitted to Cd (II) removal data. Langmuir maximum adsorption capacity of EDTA@Fe3O4/SC ncs was found to be 63.3, 22.4 and 25 mg/g that is greater than maximum adsorption capacity of Fe3O4/SC ncs that is 51, 18.9 and 15 mg/g at the adsorbent doses of 0.4, 1.2 and 2.0 g/L, respectively. Cd (II) adsorption rate is well explained by Pseudo-second order model. Cd (II) adsorption process is spontaneous and endothermic in nature expressed by Enthalpy, Entropy and Free Energy change. The results of regeneration studies showed that EDTA modified Fe3O4/SC ncs is promising, low cost and eco-friendly for heavy metal adsorption.