Bimetallic-organic framework (Fe, Cu)/carbon nanotubes encapsulated Ni nanoparticles as heterogeneous catalyst in Fenton-like process for degradation of acid orange 7 dye

Abstract

The novel heterogeneous catalyst, Bimetallic-organic framework (Fe, Cu)/carbon nanotubes encapsulated Ni nanoparticles, has been introduced for efficient degradation of acid orange 7 (AO7) via Fenton-like process. Optimizing and modeling of the heterogeneous degradation process were performed using response surface methodology (RSM) based on a five-level central composite design (CCD). The study on the individual and interaction effect of four operating parameters including pH, H₂O₂ concentration (mM), catalyst dose (mg L⁻¹) and reaction time (min) revealed that the maximum AO7 degradation efficiency (93.94%) was achieved under optimal conditions of pH = 4.0, H₂O₂ concentration = 25 mM, catalyst dose = 200.0 mg L⁻¹ and reaction time = 27 min (k = 0.1024 (min⁻¹)). Analysis of scavenging revealed that tertiary butyl alcohol (TBA) led to a notable reduction in the degradation of AO7 under optimal conditions. The degradation of AO7 dropped from 93.94% to 14.28% as TBA concentrations varied from 0 to 9 mmol L⁻¹. Consequently, the rate constant of the degradation reaction decreased from 0.1002 to 0.0058 min⁻¹ as the concentration of the quenching agent increased. Interestingly, it was found that besides the role of Fe, Cu and Ni species in the Fe_0.6Cu_0.3Ni_0.1(BDC)@CNT, surface oxygen-functional groups on the CNT provides faster and efficient Fe(III)/Fe(II) cycle over a broader pH range. Furthermore, concerning the importance of economic and environmental issues, the possibility of regenerating the Fe_0.6Cu_0.3Ni_0.1(BDC)@CNT catalyst for four consecutive cycles has been confirmed. The concluding observations of this study provide favorable outcomes in the development and utilizing the advanced MOF-based catalysts with the aim of effective environmental remediation.

Graphical Abstract