Evaluation of efficiency of copper-nickel ferrite nanoparticles loaded onto multi-walled carbon nanotubes in activation of peroxymonosulfate for degradation of reactive black dye 5 from aqueous solutions

Background and Aim: The development of industry has recently led to the release of 2 × 105 tons of colored wastewater into the environment. The presence of these solutions due to their toxicity and carcinogenic potential can be a threat to human health. The aim of this study was to investigate the efficiency of MWCNTs-CuNiFe2O4 nanocomposite in activating peroxymonosulfate (PMS) for degradation of reactive black 5 dye (RB5). Methods: In this study, nanocomposites were characterized by diagnostic techniques of SEM, TEM, FTIR, and XRD. Influence of operating parameters such as pH (2-11), nanocomposite concentration (10-750 mg/L), PMS concentration (0.25-8 mM), dye concentration (10-250 mg/L), and reaction time (0-60 min) was evaluated. Stability and scavenging tests of reactive species under optimal conditions were studied. Results: The results showed that the MWCNTs-CuNiFe2O4/PMS system has a high performance in RB5 degradation compared to systems such as PMS, MWCNTs-CuNiFe2O4 and CuFe2O4/PMS.  RB5 degradation complete was obtained at pH of 7, the composite concentration of 250 mg/L, the PMS concentration of 4 mM, and the reaction time of 15 minutes. Suitable treatment of real solutions due to the presence of interfering materials requires a reaction time above 240 min. Stability tests for 5 reaction cycles showed that MWCNTs-CuNiFe2O4 could be a recyclable catalyst in PMS activation. Conclusion: The synthesized composite can be used as a catalyst to activate PMS in RB5 dye removal due to its recyclability and high efficiency.