Browsing by Subject "Polymers of intrinsic microporosity (PIM-1)"

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Open Access
Removal of aniline from air and water by polymers of intrinsic microporosity (PIM-1) electrospun ultrafine fibers
(Academic Press, 2018) Satılmış, Bekir; Uyar, Tamer
This research aims to investigate the possibility of electrospun fibers from Polymers of Intrinsic Microporosity (PIM-1) as an alternative adsorbent for aniline removal from both air and aqueous solution. Adsorption properties of electrospun PIM-1 fibers were compared with powder and film form of PIM-1. While electrospun PIM-1 nanofibrous mat can adsorb 871 mg g−1 aniline from air, it can also adsorb 78 ± 5.4 mg g−1 aniline from aqueous environment when 50 mg L−1 aniline solution is used. The experimental maximum adsorption capacity of electrospun PIM-1 fibers was found as (qe) 138 mg g−1. Langmuir and Freundlich isotherm models have been studied and Langmuir model found more appropriate for aniline adsorption on electrospun PIM-1 fibers. The study reveals that self-standing electrospun fibrous mat of PIM-1 has shown potential to be used as an efficient adsorbent material for the adsorption of VOCs from air and aqueous system thanks to its fast kinetic and high adsorption capacity.
Open Access
Superhydrophobic hexamethylene diisocyanate modified hydrolyzed polymers of ıntrinsic microporosity electrospun ultrafine fibrous membrane for the adsorption of organic compounds and oil/water separation
(American Chemical Society, 2018) Satılmış, Bekir; Uyar, Tamer
Polymers of intrinsic microporosity (PIMs) have gained significant research interest because of their successful applications in adsorption and separation. PIM-1 is the first and most studied member of this class because it shows specific interactions with some certain organic species. Chemical modification of PIM-1, which can be achieved by simply hydrolyzing the nitrile groups in the backbone, provides an advantage of tailoring its adsorption and separation performances. In this study, electrospinning of ultrafine fibers from hydrolyzed polymer of intrinsic microporosity (HPIM) and blends of hexamethylene diisocyanate (HMDI)/HPIM was achieved in several different ratios of HMDI/HPIM ranging from 1:9 to 1:1 (w/w). Bead-free and uniform fibers were obtained in the form of self-standing ultrafine fibrous membranes, which were then thermally treated at 150 °C to introduce chemical cross-linking between HMDI units and carbonyl groups of HPIM, resulting in HMDI-modified HPIM fibrous membranes (HMDI/HPIM-FMs). The solubility behavior has been altered by an introduced modification that makes membranes insoluble in all common organic solvents. Chemical cross-linking has been confirmed by using a Fourier transform infrared technique showing urethane linkage between HMDI and HPIM, and it was further supported by X-ray photoelectron microscopy and elemental analysis techniques that show a significant increase in the relative ratio of nitrogen in HMDI/HPIM-FMs compared to HPIM-FM. The average fiber diameters of fibrous membranes were found between 1.38 ± 0.29 and 0.96 ± 0.22 μm depending on the blend compositions and applied electrospinning parameters. Moreover, the water contact-angle value for HPIM-FM increased with the introduced HMDI modification from 140 ± 4° to 159 ± 7°, changing the nature of the membrane from hydrophobic to superhydrophobic. Consequently, HMDI/HPIM-FMs were successfully employed in oil/water separation due to the superhydrophobicity. In addition, the adsorption properties of HPIMFM and HMDI/HPIM-FMs were explored for common organic solvents. While both HPIM-FM and HMDI/HPIM-FMs show promising results, the structural stability of HMDI/HPIM-FMs in liquids was found to be more stable and reusable with respect to HPIM-FM. Hence, HMDI/HPIM-FMs are more favorable for organic adsorption and separation purposes from an aqueous system.