In this study, a unique magnetic molecularly imprinted polymer (MMIP) adsorbent towards bisphenol A (BPA) as a template molecule was developed by bulk polymerization using β-cyclodextrin (β-CD) as a co-monomer with methacrylic acid (MAA) to form MMIP MAA–βCD as a new adsorbent. β-CD was hybridized with MAA to obtain water-compactible imprinting sites for the effective removal of BPA from aqueous samples. Benzoyl peroxide and trimethylolpropane trimethacrylate were used as the initiator and cross-linker, respectively. The adsorbents were characterized by Fourier transform infrared spectroscopy, scanning electronic microscopy, transmission electron microscopy, vibrating sample magnetometer, Brunauer–Emmett–Teller and X-ray diffraction.
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H nuclear magnetic resonance spectroscopy was used to characterize the MAA–βCD and BPA–MAA–βCD complex. Several parameters influencing the adsorption efficiency of BPA such as adsorbent dosage, pH of sample solution, contact time, initial concentrations and temperature as well as selectivity and reusability study have been evaluated. MMIP MAA–βCD showed significantly higher removal efficiency and selective binding capacity towards BPA compared to MMIP MAA owing to its unique morphology with the presence of β-CD. The kinetics data can be well described by the pseudo second-order kinetic and Freundlich isotherm and Halsey models best fitted the isotherm data. The thermodynamic studies indicated that the adsorption reaction was a spontaneous and exothermic process. Therefore, MMIP based on the hybrid monomer of MAA–βCD shows good potential of a new monomer in molecularly imprinted polymer preparation and can be used as an effective adsorbent for the removal of BPA from aqueous solutions.
The stoichiometry and kinetics of the oxidation of ethylenediaminetetraacetate by [Fe(phen)3] 3 +, [Fe(bipy)3] 3 + and [ComW12040] 5-were studied in aqueous HC10 a. Reaction rates were first order with respect to the oxidants and the reductant, and the dependence of the second order rate constant k2 on [H + ] is given by k2 = a + b[H+] -1.The primary products were CO2, CH20 and (CHzNH2) 2. Schuster treatment is employed to show that the reactions occur by the outersphere mechanism.
Acyl hydarazones and other hydrazones derivatives are of immense biological importance as a result of their antibacterial, antifungal, antiinflammatory properties and coordination Chemistry. The ligand was prepared by refluxing nicotinic acid hydrazide and 3-bromobenzaldehyde in ethanol, the complexes were synthezed by mixing ethanolic solutions of the metal salts with the hydrazone. The ligand and complexes were characterized on the basis of uv-visible, FTIR, melting point, conductivity, magnetic susceptibility, metal analysis and mole ratio, antimicrobial activities were determined. The ligand and complexes formed are high melting point crystalline solids. Thermodynamic stability study showed that the complexes are stable with stability constants between 2.84 x 105 – 2.21 x 107 while the solution studies gave 1:2 metal to ligand ratio. Infrared spectra data are diagnostic of bidentate coordination of the ligand via carbonyl oxygen and azomethine nitrogen atoms as result of the negative shift in the (C=O) and (C=N) bands. Effective magnetic moment of the complexes is 5.62 B.M, 4.02 B.M. and 1.81 B.M. for Manganese, Cobalt and Copper complexes respectively, the nickel complex is diamagnetic. Electronic spectra of the ligand indicate n * transitions, transition in the manganese complex is spin and orbital forbidden with very low molar absorptivity, nickel complex gave two bands assigned to 3A2g(F) 3T1g(F) and 3A2g(F) 3T1g(P) transition, cobalt complex gave one electronic band assigned to 4T1g(F) 4A2g transition. Copper complex gave one band, assigned to 2Eg 2T2g transition. On the basis of magnetic and electronic spectral of the isolated complexes octahedral geometry has been proposed for the Mn(II), Co(II) and Cu(II) complexes and square planar for the Ni(II) complex. The activities of the complexes against most of the microorganisms were enhanced compared to those of their parent ligand, with some promising potential when compared to the control drugs.
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dodecatungstocobalSummaryThe stoichiometry, kinetics and mechanism of oxidation of N-(2-hydroxyethyl)ethylenediamine triacetate by KsComW1204o, Fe(phen)~ + and Fe(bipy)~+have been studied. Each reaction is first order with respect to the oxidant and the reductant, but retarded by [H +] in the 0.20-1.60 mol dm-3 range. Simple electron exchanges are thought to occur, leading to the decarboxylation of the substrate.
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