Fabrication of rare-earth cerium-doped nickel–copper ferrite as a promising photo-catalyst for congo red-containing wastewater treatment

Abstract

Synthetic organic dyes are becoming the major class of water pollutants leading to malignant detriments to the ecology. Consequently, this research focuses on remediating this circumstance utilizing a novel catalytic material, namely, cerium-doped spinel ferrite Ni_0.6Cu_0.4Ce_xFe_2−xO₄ (x = 0.0, 0.5, 1.0, 1.5), developed using the chemical coprecipitation technique and characterized using FTIR, XRD, FE-SEM, EDX and VSM analysis. The particles have shown band gap values ranging from 4.29 to 2.01 eV. The as-synthesized nano-sized particles were employed as a photocatalyst to degrade the complex structure of congo red (CR) dye. About 91% of the dye was degraded with 60 mg of the catalyst under visible light irradiation with the highest cerium-doping (x = 1.5) at a pH below 6.8, which was the zero-surface charge pH for the particle. Batch studies were performed to optimize all the conditions, including the dose, concentration, pH, and different light energy sources. Recyclability of the catalyst was also investigated, which was supported by the higher stability of the recovered particles through XRD analysis. Reaction kinetics for this system were evaluated along with three isotherm models. Moreover, the scavenging test indicated that the major active species leading to this degradation was hole (h⁺), and a schematic degradation mechanism is presented. Following that, this model can successfully be used for wastewater treatment.