Synthesis, Spectral, Morphology, Thermal Degradation Kinetics and Antibacterial Studies of Terpolymer Metal Complexes

Polymeric nanocomposites for the removal of Acid red 52 dye from aqueous solutions: Synthesis, characterization, kinetic and isotherm studies

Polymeric nanocomposites polyaniline-polyvinylpyrrolidone (PAPV) and polyaniline-polyvinylpyrrolidone-neodymium/zinc oxide (PAPV-NZO) were synthesized for the effective dye removal through adsorption process. Neodymium doped zinc oxide (NZO) with various proportions of neodymium were prepared by chemical co-precipitation method and incorporated into the copolymer matrix via oxidative polymerization technique. NZO nanoparticles were characterized by X-ray diffraction (XRD) and the morphological features, and functional group linkages of the PAPV-NZO were confirmed by scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) analyses. Acid red 52 dye was chosen as a synthetic toxic effluent to study the removal efficiency of the nanocomposites with different parameters viz. time, concentration, adsorbent dosage and pH. The studies were performed under visible light irradiation and the residual dye concentration was analyzed by UV-visible spectrophotometer. PAPV-NZO exhibited greater dye removal rate than PAPV due to the incorporation of NZO that enhanced the conducting nature, stability and surface area of PAPV-NZO. The optimum concentration of the dye and the adsorbent dosage of the PAPV-NZO were determined to be 80 ppm and 50 mg, respectively. At acidic condition of pH 2, the removal capacity of PAPV-NZO was found 99.6%. Kinetic and isotherm models have been studied on the optimum parameters to investigate the nature of the adsorption process. The process followed pseudo second order kinetics and was best suited to the Langmuir model. The maximum dye adsorption capacity of PAPV-NZO was estimated to be 159.36 mg g^-1. From the results, it can be assured that the PAPV-NZO can be effectively used for the removal of dye pollutants in water.

Antimicrobial applications of transition metal complexes of benzothiazole based terpolymer: synthesis, characterization, and effect on bacterial and fungal strains

Terpolymer of 2-amino-6-nitro-benzothiazole-ethylenediamine-formaldehyde (BEF) has been synthesized and characterized by elemental analysis and various spectral techniques like FTIR, UV-Visible, and ¹H and ¹³C-NMR. The terpolymer metal complexes were prepared with Cu²⁺, Ni²⁺, and Zn²⁺ metal ions using BEF terpolymer as a ligand. The complexes have been characterized by elemental analysis and IR, UV-Visible, ESR, ¹H-NMR, and ¹³C-NMR spectral studies. Gel permeation chromatography was used to determine the molecular weight of the ligand. The surface features and crystalline behavior of the ligand and its complexes were analyzed by scanning electron microscope and X-ray diffraction methods. Thermogravimetric analysis was used to analyze the thermal stability of the ligand and its metal complexes. Kinetic parameters such as activation energy (E_a) and order of reaction (n) and thermodynamic parameters, namely, ΔS, ΔF, S*, and Z, were calculated using Freeman-Carroll (FC), Sharp-Wentworth (SW), and Phadnis-Deshpande (PD) methods. Thermal degradation model of the terpolymer and its metal complexes was also proposed using PD method. Biological activities of the ligand and its complexes were tested against Shigella sonnei, Escherichia coli, Klebsiella species, Staphylococcus aureus, Bacillus subtilis, and Salmonella typhimurium bacteria and Aspergillus flavus, Aspergillus niger, Penicillium species, Candida albicans, Cryptococcus neoformans, Mucor species fungi.