Restricted Access: On the Nature of Adsorption/Desorption Hysteresis in Amorphous, Microporous Polymeric Materials

Jeromenok, Jekaterina; Weber, Jens

doi:10.1021/la402630s

Cited by 172 publications

(142 citation statements)

References 46 publications

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“…Such an abnormal dualmode isotherm has been reported for polymeric samples by Van der Vegt et al (2010) and associated to swelling effect (formation of new pores and dissolution of gas molecules in dense matrix). Jeromenok and Weber have associated this effect to the increased solvation pressure in the matrix, which acts as the driving force for filling the pores with restricted access (Jeromenok and Weber 2013). In the present case, the dual-mode isotherm of the sample can be associated to its typical morphology, formed by the interconnection or aggregation of small nanoparticles.…”

Section: Raman Spectroscopic Studymentioning

confidence: 67%

Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

et al. 2015

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CuS nanoparticles (NPs) of few nanometers in size were prepared by a wet chemical method. The structural, compositional, and optical properties of the NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, micro Raman and Fourier transform infrared spectroscopy, N 2 adsorption-desorption isotherms, and UV-Vis diffuse reflectance spectroscopy. The XRD pattern proved the presence of hexagonal phase of CuS particles which was further supported by Raman spectrum. The estimated band gap energy of 2.05 eV for the slightly sulfur-rich CuS NPs is relatively larger than that of bulk CuS (1.85 eV), indicating the small size effect. As-prepared NPs showed excellent photocatalytic activity for the degradation of methylene blue (MB) under visible light. The surface-bound OH -ions at the CuS nanostructures help adsorb MB molecules facilitating their degradation process under visible light illumination. The studies presented in this paper suggest that the synthesized CuS NPs are promising, efficient, stable, and visible-light-sensitive photocatalyst for the remediation of wastewater polluted by chemically stable azo dyes such as MB.

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Section: Raman Spectroscopic Studymentioning

confidence: 67%

Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

et al. 2015

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“…In these experiments Fig. 22,40,41 This experiment indicated that the degassing procedure (under vacuum at 80 C) may have resulted in kinetic pore closure assisted by the physical crosslinking of the pyrene. the equilibration intervals were increased in order to address the incomplete equilibration observed in our earlier N 2 isotherms (Fig.…”

Section: Resultsmentioning

confidence: 91%

Using intermolecular interactions to crosslink PIM-1 and modify its gas sorption properties

et al. 2015

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The intermolecular interactions between the "polymer of intrinsic microporosity" PIM-1 and polycyclic aromatic hydrocarbons (PAHs) have been investigated with the aim of modifying the gas sorption and physical properties. Mixing PIM-1 with selected PAHs resulted in rapid precipitation of polymer. Blending PIM-1 with pyrene had a significant effect of the gas sorption properties of the resulting films; dramatically reduced N 2 uptake (77 K), whilst CO 2 uptake at 298 K was only slightly reduced. A gateopening behaviour was also observed for the N 2 gas sorption (77 K), which was related to the pyrene content of the blend. Using an electron-donating PAH as the additive resulted in a stronger interaction.By exploiting a post-modification strategy after PIM-1 film formation, the absorption of either pyrene or 1-aminopyrene produced films with higher elastic moduli and greatly improved CO 2 /N 2 gas sorption selectivities (293 K). Single gas permeability measurements revealed that while the 1-aminopyrene modified film possessed reduced CO 2 permeability, it possessed enhanced CO 2 /N 2 selectivity. Importantly, the ageing of the permeability was halted over the 50 days tested, likely due to the physical crosslinking of the polymer chains by 1-aminopyrene. † Electronic supplementary information (ESI) available: The ESI contains further photographs investigating the precipitation of PIM-1 into solutions of pyrene. Dynamic light scattering analysis of PIM-1 precipitation with pyrene, gas sorption data comparing the effect of length of time used for the methanol soaking of PIM-1 lms, a photograph of PIM-1 and PAH blends dried to give lms, UV-Vis data for the relationship between pyrene concentration in solution and the amount of pyrene absorbed by the PIM-1 lm, visual and SEM comparison of post-modied PIM-1 lms, and transmission UV-Vis of PIM-1 lms post-modied with pyrene. See

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“…The reason for the differences might be a result of the different sterical demands of the monomers included in the networks. The hysteresis in the low pressure range of both networks is indicative of the presence of restricted-access pores 63 and to the swelling of the network during the gas uptake. The latter one is probably also responsible for the small hysteresis observable for all CO 2 isotherms (Fig.…”

Section: Gas Sorption Propertiesmentioning

confidence: 99%

Porous imine-based networks with protonated imine linkages for carbon dioxide separation from mixtures with nitrogen and methane

et al. 2015

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Porous imine-linked networks (PINs) have been prepared by catalyst-free Schiff base condensation of 2,4,6-(4-aminophenyl)1,3,5-triazine with 9,10-anthracene-dicarboxaldehyde (PIN1 and PIN1_2) and with 4,4 0 ,4 00 ,4 000 -methanetetrakis-benzaldehyde (PIN2). Even after synthesis optimisation, only with DMSO (PIN1 and PIN2) microporous frameworks were obtained, whereas DMF (PIN1_2) and other solvents led to nonporous systems, estimated by argon measurements. Furthermore, 15 N solid state NMR and IR spectroscopy reveal the influence of the decomposition products of DMSO leading to protonation of the imine linkage and resulting in an ionic structure with an incorporated sulfonic counterion. Until now, protonation of an imine function due to the usage of DMSO as solvent has not been discussed in the literature. In contrast, for PIN1_2 the imine linkage remains neutral. Argon sorption isotherms for PIN1 and PIN2 exhibit surface areas of 458 m 2 g À1 and 325 m 2 g À1 and the pore structure displays micro-and small mesopores with pore diameters from 0.6 to 5 nm. Additionally, CO 2 isotherms at 273 K demonstrate ultramicropores for all three polymers with similar pore size distributions. Despite their different network structures, similar CO 2 uptakes (1.8-1.06 mmol g À1 at 273 K at 1.0 bar) and heat of adsorption Q st values of 30 kJ mol À1 were obtained. In line with the polyionic character of PIN1 and PIN2, both compounds adsorb three times more water than the more hydrophobic, neutral PIN1_2 at room temperature indicating two different adsorption mechanisms. IAST selectivity calculations show good CO 2 /N 2 (30-31) and CO 2 /CH 4 (8-12) selectivity factors. Despite their moderate BET-surface areas, the PINs show good CO 2 uptakes and selectivity factors.

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Restricted Access: On the Nature of Adsorption/Desorption Hysteresis in Amorphous, Microporous Polymeric Materials

Cited by 172 publications

References 46 publications

Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

Using intermolecular interactions to crosslink PIM-1 and modify its gas sorption properties

Porous imine-based networks with protonated imine linkages for carbon dioxide separation from mixtures with nitrogen and methane

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