Synthesis and characterization of the Cu(II)-quinoxaline, 3,3-thiodipropionate mixed ligand coordination polymer for the removal of methylene blue from aqueous solution.

Herein, we report the removal of methylene blue (MB) dye from water by Cu(II)-quinoxaline, 3,3-thiodipropionate mixed ligand coordination polymer synthesized as [Cu₂(TDPH)₄(QNX)]·DMF. Characterization of the synthesized material was carried out by elemental analysis, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), BET surface area analysis, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and UV–visible spectroscopy. ν(C = O) and ν(C–O) absorption bands were detected at 1735 and 1093 cm⁻¹, respectively, while ν(C = N) was observed at 1608 cm⁻¹ in the synthesized compound. The synthesized material was used as adsorbent for the removal of MB dye from aqueous solution using batch adsorption technique. The maximum adsorption capacity was found to be 7.9745 mg/g, while the maximum decolorization efficiency for the adsorbent was observed to be 99.04%. Adsorption data from the study fitted the Langmuir isotherm with an R² value of 0.9815, while the adsorption kinetics followed the pseudo-second-order kinetic model with an R² value of 0.9953. The results obtained from the study, therefore showed that the synthesized materials could be used as adsorbents in wastewater treatment. [ABSTRACT FROM AUTHOR]