High-Performance Recyclable Magnetic CuFe_2–<i>x</i>Cr_<i>x</i>O₄ Nanocatalysts for Facile Reduction of Nitrophenols and Photooxidative Degradation of Organic Dyes

Remediating pollutants in water sources is essential for preserving and protecting our water resources. Water pollution can have severe environmental, economic, and public health consequences. Water scarcity for domestic purposes can eventually be addressed by improving wastewater management. In the present study, highly active and magnetically separable Cr-doped copper ferrites CuFe2–xCrxO4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) were synthesized via a sol–gel technique and employed for the conversion of nitrophenols to aminophenols and photooxidative deterioration of various dyes such as methyl orange (MO), rhodamine B (RhB), and methylene blue (MB), as well as their ternary solution (RhB + MO + MB). Powder X-ray diffraction investigation indicates that the prepared phases are well indexed in the Fd3̅ m space group except for CuFe2O4, which crystallizes in the I41/amd space group. The M–H hysteresis loop results support the ferromagnetic behavior of the nanophases, which makes them magnetically separable. The optical-band-gap energies of prepared nanostructures were found to be in the range of 1.70–1.39 eV, which makes them appropriate and reliable photocatalysts. CuFe2O4 was found to be the most efficient nanocatalyst toward the conversion of nitrophenols to aminophenols, while CuCrFeO4 showed a maximum degradation efficiency for the deterioration of dyes. The kinetic models correctly explain both reduction and photodegradation processes using pseudo-first-order kinetics. Further, several recyclability runs demonstrated that the nanocatalysts were extremely stable and reusable. This study reflects the possibility of employing mesoporous nanocatalysts for practical applications in the treatment of wastewater