Capability of copper-nickel ferrite nanoparticles loaded onto multi-walled carbon nanotubes to degrade acid blue 113 dye in the sonophotocatalytic treatment process.

In this study, copper-nickel ferrite (CuNiFe2O4) nanoparticles were successfully loaded onto multi-walled carbon nanotubes (MWCNTs) by using the coprecipitation method and used as new catalysts (MWCNT-CuNiFe2O4) in the sonophotocatalytic degradation process of the acid blue 113 (AB113) dye. The success of the MWCNT-CuNiFe2O4 synthesis and its properties were determined by analyzing it using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). A high efficiency of dye removal (100%), total organic carbon (93%), and chemical oxygen demand (95%) were achieved with the following conditions: pH of dye solution = 5, MWCNT-CuNiFe2O4 dosage = 0.6 g/L, AB113 dye concentration = 50 mg/L, UV light intensity = 36 W, ultrasonic wave frequency = 35 kHz, and treatment time = 30 min. The kinetic results revealed that the efficiency of the sonophotocatalytic process using MWCNT-CuNiFe2O4 was higher than that of the sonolysis, photolysis, photocatalysis, and sonocatalysis processes. Scavenging studies demonstrated that the holes (h+) and hydroxyl radical (•OH) were the main reactive species for the AB113 dye degradation. The stability and recyclability of MWCNT-CuNiFe2O4 were confirmed with eight consecutive cycles for a maximum efficiency of more than 92%. The high rate of BOD5/COD indicated that the sonophotocatalytic process had the potential to degrade the dye into degradable compounds. The toxicity study with an Escherichia coli growth inhibition rate emphasized that MWCNT-CuNiFe2O4 in the sonophotocatalytic degradation process of the AB113 dye had a significant effect on reducing toxicity, when compared to processes of photolysis and photocatalysis. During the sonophotocatalytic process using MWCNT-CuNiFe2O4, the AB113 dye was mineralized into CO2, H2O, NH4+, NO3-, and SO42-. The results of the present study proved that the MWCNT-CuNiFe2O4-based sonophotocatalytic process was a promising dye degradation technology to protect the aquatic environment.