Kinetic removal of Cr6+ by carboxymethyl cellulose-stabilized nano zerovalent iron particles

Abstract

Carboxymethyl cellulose (CMC) was used in the chemical reduction method for producing dispersible nano zerovalent iron (nZVI) particles served as reactive, mobile and convenient adsorbent. CMC-stablized nZVI particles at CMC:Fe2+ = 0.0034 molar ratio were characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy assisted with probe ultrasonication dispersing tool. FTIR depicted that the CMC monomers were adsorbed onto nZVI particles primarily through carbonyl head groups via monodentate bonding. The botryoidally clusters were the predominant morphology of CMC-stablized nZVI particles under SEM observation. Those spherical particles were evenly dispersed at sizes less than 100 nm under TEM analysis. nZVI particles stabilization with CMC (at CMC:Fe2+ molar ratio of 0.0050) prevented the aggregation and resulted in high catalytic reactivity observed at pseudo-first order constant value, K1 of 0.0196 min-1 for Cr6+ removal in contaminated aqueous. This study demonstrates that CMC-stablized nZVI particles has the potential to become an effective agent for in-situ subsurface environment remediation.