This study reports the feasibility of recycled polyvinylidene difluoride (PVDF) beads to decolourize the methylene blue (MB) from aqueous streams. The beads were characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR) for its morphological and structural analysis. The effect of various process parameters such as adsorbent dose, initial concentration, contact time, and pH was studied. The first principle density functional theory (DFT) calculations were performed to investigate the underlying mechanism behind the adsorption process. The MB dye adsorption on recycled PVDF beads followed the pseudo-second-order kinetics and Langmuir isotherm, indicating the adsorption was chemical and monolayer. The maximum adsorption capacity obtained was 27.86 mg g−1. The adsorption energy of MB-PVDF predicted from the DFT study was –64.7 kJ mol−1. The HOMO-LUMO energy gap of PVDF decreased from 9.42 eV to 0.50 eV upon interaction with MB dye due to the mixing of molecular orbitals. The DFT simulations showed that the interaction of the MB dye molecule was from the electronegative N atom of the MB dye molecule, implying that electrostatic interactions occurred between the recycled PVDF beads and the positively charged quaternary ammonium groups in MB dye. The present study demonstrates the potential of recycled PVDF beads for a low-cost dye removal technique from textile wastewater.

  • We synthesized the CuBTC/ZnO chitosan composite for the adsorptive removal of methylene blue dye.

  • Photocatalytic regeneration of composite was performed to check the reusability of the synthesized adsorbents.

  • The active oxygenated species generated by the ZnO on the contaminated water was found to be responsible for the degradation of dye.

  • Adsorbent can be used for up to 5 cycles for the Removal of methylene blue.

Graphical Abstract

Graphical Abstract
Graphical Abstract
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