Catalysts based on Co, amino acids, and 2,2-bipyridine present an attractive and economic alternative in ring opening polymerization, and possess advantageous ligand coordination properties combined with a variety of accessible oxidation states and coordination geometries.
This investigation addresses the design of a series of poly(acrylonitrile-butadiene-styrene)/polyacrylonitrile-zinc oxide(ABS/PAN-ZnO) membranes by coaxial electrospinning. In the first instance, an optimization of ABS and PAN electrospinning was performed, thus establishing suitable compositional and processing parameters for obtaining homogenous fibers. Then, coaxial electrospinning of ABS and PAN solutions containing different amount of ZnO nanoparticles was carried out. The coaxial morphology of the nanofibers and ZnO distribution/dispersion were studied by the combination of several techniques such as scanning electron microscopy, X-ray energy dispersive analysis, contact angle, and thermogravimetric analysis. The performance of the obtained membranes for chromium (VI) ions removal from aqueous solutions was assessed by photoreduction using ultraviolet-visible spectroscopy. Electrospun mats composed of ABS (core)/PAN (sheath) embedded with 30 wt % of ZnO nanoparticles exhibited the highest chromium photoreduction (about 80%), suggesting the potential use of these membranes as filters for water purification.
A bioinspired Co(iii) catalyst efficiently transforms epoxides and CO2 into cyclic carbonates. The mechanism was found to combine the cooperative effects of the metal center and amino acid residues in the outer coordination sphere.
In this research work, the coaxial electrospinning technique was used for the development of composite membranes based on poly(acrylonitrile-butadiene-styrene)/polyacrylonitrile (ABS/PAN) micrometer fibers loaded with ZnO nanoparticles (NpZnO) in order to evaluate their efficiency in the photoreduction of Cr VI ions in aqueous solutions. The morphological analysis of the fibers was carried out by means of scanning electron microscopy (SEM), the chemical composition of the materials was determined by Fourier transformed infrared spectroscopy (FTIR) with attenuated total reflectance (ATR), the crystallinity of the nanoparticles in the fibrous materials was analyzed by X-ray diffraction (XRD) and the residual Cr VI concentration was measured with the Nesslerizations method. It was demonstrated that by means of the electrospinning technique it is possible to manufacture coaxial fibers based on ABS/PAN with homogeneous morphology with mean diameters of 1.1 µm. Furthermore, through this technique it was possible to obtain ABS/PAN-NpZnO composite coaxial fibers with concentrations of 15, 25 and 30 wt.% of NpZnO, thus favoring the increase in the dose of the photocatalyst. The maximum efficiency of said membrane was obtained with 30 % wt.% of NpZnO with respect to the total solid, allowing the reduction of Cr VI to 81.59 % after 8 h with a substrate concentration of 50 mg/l. Therefore, ABS/PAN-NpZnO fibers are promising candidates for applications related to environmental remediation, such as water regeneration filters, thus partially contributing to the development of sustainable technologies.
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