Fabrication of PVDF/ZIF-8 Composite Membrane via In-Situ Growth for Adsorptive Removal of Methyl Green from Aqueous Solution

The widespread use of organic dyes in industrial processes has led to increasing environmental pollution due to the discharge of dye-contaminated wastewater, necessitating more efficient dye removal methods. In this study, a poly(vinylidene fluoride) (PVDF)/ZIF-8 composite membrane was fabricated via a phase inversion method using immersion precipitation, with ZIF-8 synthesized via in-situ growth within the membrane matrix. The composite membranes were thoroughly characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). The ZIF-8 particles were uniformly distributed in the PVDF/ZIF-8 composite membrane. The adsorption performance of the PVDF/ZIF-8 composite membrane was evaluated for methyl green (MG) removal. At 313 K with an adsorbent dose of 10 mg, the membrane exhibited an adsorption capacity of 172.30 mg g(-)(1) and a removal ratio of 87.21%, demonstrating that the incorporation of ZIF-8 significantly enhanced adsorption performance. Adsorption isotherm studies revealed that the process followed the Freundlich model, while kinetic analysis indicated a pseudo-second-order mechanism. Additionally, thermodynamic investigations suggested that the adsorption was endothermic and spontaneous. The major driving force for adsorption was identified as electrostatic interactions between the dye and the membrane. These findings highlight the potential of PVDF/ZIF-8 composite membranes for effective dye removal from wastewater.