0000000000283334
AUTHOR
Freek Kapteijn
showing 10 related works from this author
PBI mixed matrix hollow fiber membrane: Influence of ZIF-8 filler over H2/CO2 separation performance at high temperature and pressure
2020
High performance and commercially attractive mixed-matrix membranes were developed for H2/CO2 separation via a scalable hollow fiber spinning process. Thin (~300 nm) and defect-free selective layers were successfully created with a uniform distribution of the nanosized (~60 nm) zeolitic-imidazole framework (ZIF-8) filler within the polymer (polybenzimidazole, PBI) matrix. These membranes were able to operate at high temperature (150 °C) and pressure (up to 30 bar) process conditions required in treatment of pre-combustion and syngas process gas streams. Compared with neat PBI hollow fibers, filler incorporation into the polymer matrix leads to a strong increase in H2 permeance from 65 GPU t…
Cation influence in adsorptive propane/propylene separation in ZIF-8 (SOD) topology
2019
Separation of propylene/propane is one of the most challenging and energy consuming processes in the chemical industry. Propylene demand is increasing and a 99.5% purity is required for industrial purposes. Adsorption based solutions are the most promising alternatives to improve the economical/energetic efficiency of the process. Zeolitic Imidazolate Frameworks (ZIFs) combine the desired characteristics from both MOFs and zeolites: tunability and flexibility from metal organic frameworks, and exceptional thermal and chemical stability from zeolites. In order to enlighten the role of the cation in the sodalite ZIF-8 framework for propane/propylene separation, dynamic breakthrough measuremen…
The oxamate route, a versatile post-functionalization for metal incorporation in MIL-101(Cr): Catalytic applications of Cu, Pd, and Au
2013
Abstract A new consecutive post-functionalization method has been developed for the inclusion of additional metal functionalities in Metal Organic Frameworks (MOFs) through oxamate as chelating agent. This may result in catalytic centers of metal–organic complexes or in controlled formation of metal nanoparticles, demonstrated for Cu, Pd and Au, in the highly stable MIL-101(Cr) framework. In a first post-synthesis step, reduction of the NO 2 -MIL-101(Cr) leads to the formation of NH 2 -MIL-101(Cr). The second functionalization consists of a straightforward condensation of the amino groups of the ligand with ethyl chloro-oxoacetate resulting in the formation of free oxamates attached to the …
Magnetic properties of Co–Al, Ni–Al, and Mg–Al hydrotalcites and the oxides formed upon their thermal decomposition
2002
The magnetic behaviour of Co–Al, Ni–Al, and Mg–Al hydrotalcites (HTlc) with a M2+/Al3+ molar ratio of 3 and carbonates in the interlayer, as well as the mixed oxides obtained after calcination at 823 K for 5 h, has been investigated by DC and AC magnetic susceptibility measurements and isothermal magnetisation. The samples were also characterised by ICP-OES and XRD. The magnetic measurements show that Co–Al and Ni–Al HTlcs behave as ferromagnets, with ordering temperatures of approximately 6–7 K in both cases, and displaying hysteresis loops at 2 K with coercive fields of 4.2 and 5.5 mT, respectively, whereas the Mg–Al-HTlc shows the expected diamagnetic behaviour. A solid solution of cobal…
Steam-activated FeMFI zeolites. Evolution of iron species and activity in direct N2O decomposition
2003
Abstract In this paper the effect of the composition and steaming conditions of FeMFI catalysts on activity in direct N2O decomposition is investigated. MFI zeolites with different framework compositions (FeAlSi, FeGaSi, and FeSi) and without iron ( 100 mbar H2O in N2) favor the extraction of framework iron, enabling the application of lower activation temperatures. The optimum temperature during steam activation is that at which extraction of framework iron is complete without extensive clustering of extra-framework iron species into oxide particles, as was demonstrated by transmission electron microscopy and electrochemical characterization of the samples. Additional experiments show…
Highly selective chemical sensing in a luminescent nanoporous magnet.
2012
Among the wide variety of properties of interest that a given material can exhibit, luminescence is attracting an increasing attention due to its potential application in optical devices for lighting equipment and optical storage, [ 1a − c] optical switching, [ 1d ,e] and sensing. [ 1f − i ] At this respect, many scientists, working in the multidisciplinary fi eld of the materials science, have directed their efforts to the obtention of luminescent materials with potential sensing applications. For instance, sensitive and selective detection of gas and vapor phase analytes can result specially interesting because of the variety of applications that can be found in many different fi elds. A …
Selective Gas and Vapor Sorption and Magnetic Sensing by an Isoreticular Mixed-Metal–Organic Framework
2012
A novel isoreticular oxamato-based manganese(II)-copper(II) open metal-organic framework H(2)O@iso1 featuring a pillared square/octagonal layer structure with alternating open and closed octagonal pores has been rationally prepared. The open-framework topology is responsible for a large selectivity in the separation of small gas (CO(2) over CH(4)) and vapor molecules (CH(3)OH over CH(3)CN and CH(3)CH(2)OH). H(2)O@iso1 displays a long-range three-dimensional ferromagnetic ordering with a drastic variation of the critical temperature as a function of the guest molecule [T(C)2.0 K (CO(2)@iso1 and CH(4)@iso1) and T(C) = 6.5 (CH(3)OH@iso1) and 21.0 K (H(2)O@iso1)].
Xenon Recovery by DD3R Zeolite Membranes: Application in Anaesthetics.
2019
Xe is only produced by cryogenic distillation of air, and its availability is limited by the extremely low abundance. Therefore, Xe recovery after usage is the only way to guarantee sufficient supply and broad application. Herein we demonstrate DD3R zeolite as a benchmark membrane material for CO2 /Xe separation. The CO2 permeance after an optimized membrane synthesis is one order magnitude higher than for conventional membranes and is less susceptible to water vapour. The overall membrane performance is dominated by diffusivity selectivity of CO2 over Xe in DD3R zeolite membranes, whereby rigidity of the zeolite structure plays a key role. For relevant anaesthetic composition ( 320 h). Thi…
Physicochemical Characterization of Isomorphously Substituted FeZSM-5 during Activation
2002
Physicochemical characteristics of isomorphously substituted FeZSM-5 both after preparation and after activation have been determined by gas (Ar and N2) physisorption, 27Al and 29Si magic-angle spinning–nuclear magnetic resonance, NH3 temperature-programmed desorption, transmission electron microscopy, H2 temperature-programmed reduction (TPR), 57Fe Mossbauer spectroscopy, and voltammetric response techniques. The activation of as-synthesized FeZSM-5 comprises calcination at 823 K and a subsequent steam treatment (300 mbar of H2O in N2) at 873 K. Calcination leads to complete removal of the template. During this process a significant fraction of iron is dislodged to extraframework positions…
Electrochemical characterization of iron sites in ex-framework FeZSM-5
2002
Abstract The electrochemical response of FeZSM-5 prepared by an ex-framework method has been studied using Paraloid B72 polymer film electrodes immersed in aqueous media using H2SO4, HCl, Na2EDTA and NaCl electrolytes. The ex-framework method comprises the hydrothermal synthesis of isomorphously substituted FeZSM-5, followed by calcination at 823 K and subsequent steam treatment (300 mbar H2O in N2) at 873 K. During this process iron is extracted to extra-framework positions. Also partial dealumination of the zeolite framework takes place. Characteristic voltammetric responses in the +1.0 to −0.6 V versus SCE potential range have been recorded and were used to characterize the iron species …