Adsorption and visible light driven photocatalytic degradation of Malachite Green and Methylene Blue dye in wastewater using magnetized copper metal organic framework

Abstract

The rising concern about the environmental pollution, particularly due to the setup of more industrial sectors has grabbed the attention of scientists and researchers. Many textile businesses emit Malachite Green and Methylene Blue (MG and MB) into the atmosphere, posing serious health risks. In this study, a copper metal-organic framework doped with iron nanoparticles (Cu-MOF@Fe3O4) was synthesized utilizing the slow evaporation approach, commencing with cuprous chloride and 2-mercaptobenzimidazole in a 1:2 ratio. Cu-MOF@Fe3O4 was characterized using a variety of techniques, including FTIR, SEM, and DRS analysis. The SEM analysis showed a rough and uneven morphology for the Cu-based MOFs. The XRD analysis confirmed the crystallinity of the products. The average crystallite size for Cu-MOF, Fe3O4 nanoparticles and Cu-MOF@Fe3O4 were found to be 0.22, 1.00, and 1.00 nm. While the surface area of Cu-MOF was found to be 213.192 m2g−1 while in Cu-MOF@Fe3O4 it shows an increase, i.e., 218.268 m2g−1 as calculated through the iodometric method. A series of experiments were conducted to assess the surface area, chemical oxygen demand (COD), limit of detection (LOD) (0.065559, 0.0136), limit of quantification (LOQ) (0.198662, 0.041312), point of zero charge (PZC) (5.2), pH levels (6, 7), contact times (10, 25 min), photocatalyst dosages (0.3, 0.05 g), dye concentrations (2, 10 µg/mL), and temperature effects (50°, 90°) on the adsorption and photocatalytic degradation of MG and MB, respectively. Photodegradation of both dyes followed pseudo-second order kinetics with R 2 values of 0.9833 (MG) and 0.8875 (MB). The adsorption isotherms (Freundlich and Langmuir) for MG and MB dye were analyzed and the experimental data holds a good correlation with Freundlich isotherm. The sample application of Cu-MOF@Fe3O4 as a photocatalyst, has high efficiency,  % photocatalysis (96.9 % MG, 99.4 % MB) with reusability (95–100 %) upto 10 cycles to photodegrade MG and MB dye in wastewater. To the best of our knowledge, this is the first report on the deployment of copper-based MOFs-doped with magnetite for the photocatalytic degradation of MG and MB dyes.