Experimental and density functional theory investigation on one- and two-dimensional coordination polymers and their ZnO-doped nanocomposite materials for wastewater remediation

Two Cd(II) and Cu(II) coordination polymers (CPs) with the compositions of [Cd(HIPA)(HIZ)(H2O)(2)](n)center dot 3H(2)O (CP1) and [Cu(HIPA)(HIZ)(2)](n)center dot 2H(2)O center dot MeOH (CP2), where, (H(3)IPA = 5-hydroxy isophthalic acid, and HIZ = imidazole), were successfully obtained by the reaction of the mixed ligand of H(3)IPA and HIZ under solvothermal conditions. The prepared CPs were characterized by X-ray diffractions (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-visible spectroscopy, thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) analysis, and microscopic (TEM and SEM) techniques. The complexes 1 and 2 shows dual behavior as adsorbent and photocatalyst for the adsorption and photocatalytic degradation of methyl blue (MB), methyl orange (MO), and crystal violet (CV) dyes. Additionally, zinc-oxide doped composite materials (ZnO@CP1 and 2) were also synthesized using solvothermal and mechanochemical solid grinding methods. Compared with the parent coordination frameworks (CP1 and CP2), the composites (ZnO@CP1 and 2) exhibited slightly improved surface area with reduced photogenerated electron-hole ratio, hence displayed good photo degradation activity. Moreover, the density functional theory (DFT/B3LYP) with the counterpoise and dispersion corrections was employed to validate dyes adsorption mechanism with the reported CPs.

Automated summary

Two Cd(II) and Cu(II) coordination polymers were successfully synthesized and exhibited good adsorption and photocatalytic degradation performance for dyes. Additionally, zinc-oxide doped composite materials showed improved surface area and degradation activity compared to the parent coordination frameworks. The adsorption mechanism of dyes was validated using density functional theory.