Optimization of the effect of microelectrodes on Ni2+ removal in three-dimensional electrode system.

This study investigated Ni+2 removal performance in 3DER reactors where electrocoagulation mechanisms and microelectrodes are used together. EDTA modification was carried out on the granule-activated carbon surface to increase the efficiency and affinity of microelectrodes against Ni+2 molecules. The grafting was examined using BET, FT-IR, SEM, EDS, and the elemental mapping methods. With the surface analyses made in this study, it was revealed that EDTA modification on granulated activated carbon was successfully performed. Also, 8.48%wt by mass of EDTA grafting on granular activated carbon was possible. EDTA functionalization did not affect the surface pore structures of CAC much. Under 10 V potential, 97.82% Ni removal efficiency was obtained with 2D in 35 min, while 96.69% removal in 10 min and 100% removal in 15 min were obtained in the 3D reactor. The Ni+2 removal mechanism in 3DER reactors has been determined to conform to the pseudo-second-order kinetic model. The k2 value obtained for 10 V (1.36 10-2) is 27 times the k2 value obtained for 5 V for 3DER reactors. In addition, using central composite design (CCD), operational parameters such as time, concentration, and potential difference affecting Ni+2 removal in 3DER reactors have been optimized. The most influential parameter is the applied voltage, followed by time and concentration. It has been determined that 3DER reactors using EDTA-modified microelectrodes are highly efficient and suitable for Ni+2 removal.