X-ray micro computed tomography and efficient electrochemical recovery of lanthanides on porous carbon cylinder electrodes

Porous carbon cylinder (PCC) electrodes were prepared by thermal treatment of used corn starch packaging materials at 800 °C under Ar condition. The recycled PCC electrodes were first used to successfully recover lanthanide (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb) ions in a 0.1 M NaClO4 electrolyte by amperometry electrodeposition. The electrodeposited materials were characterized by scanning electron microscopy, X-ray diffraction crystallography, energy dispersive X-ray spectroscopy, Raman spectroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, temperature programmed reaction spectrometry, fluorescence (FL) spectroscopy, and real-time FL measurement for electrodeposition kinetic analysis. X-ray Micro computed tomography (X-ray micro-CT) was first successfully employed to examine open and closed pore 3D images for PCC before and after electrodeposition. Hydrogen storage property of PCC was also demonstrated. The present study showed very unique information for the preparation of PCC by recycling of used corn starch packaging materials, hydrogen storage, electrochemical recovery of lanthanide elements using the PCC, and inner and exterior 3D image processing of PCC using X-ray micro-CT.