Synthesis of agar-stabilized nanoscale zero-valent iron particles and removal study of hexavalent chromium

In this study, agar-stabilized nanoscale zero-valent iron (A-nZVI) was synthesized using a rheological phase reaction method. The structure and morphology of A-nZVI particles were investigated by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and Fourier-transform infrared spectrometry. Batch removal experiments showed that the pH value of solution, hexavalent chromium [Cr(VI)]/A-nZVI mass ratio and reaction time have significant effects on the removal of Cr(VI). A 100 % removal of Cr(VI) was achieved when applying 50 mg L-1 of Cr(VI) at the optimal pH value of 3 and the Cr(VI)/A-nZVI molar ratio of 0.025 with the reaction time of 2 h at room temperature. The removal rates of Cr(VI) were fitted to the modified pseudo-first-order kinetic equations with respect to Cr(VI) concentrations.