Mixture Of ZSM-5 Research Articles

Thermocatalytic degradation of common polymers: A microscale combustion calorimetry study

This paper presents the first application of the microscale combustion calorimetry (MCC) to study catalyzed pyrolysis of the practical polymers comprising most of currently produced plastic wastes. The polymers considered include olefines (HDPE, LDPE, and PP), PS, PMMA, PET, PC, and PVC. Each of the polymers is mixed with one of the two catalysts, ZSM-5 or MgO, and the measurements are undertaken for the catalyst mass fractions of 0.1, 0.2, and 0.3 at several heating rates ranging from 15 to 60 K/min. Strong catalytic effect of ZSM-5 has been demonstrated for the polyolefin polymers (HDPE, LDPE, and PP). Such effect manifests itself in a significant reduction of characteristic pyrolysis temperatures and apparent activation energy; the latter is shown to decrease greatly (by a factor of about two) when the catalyst is added. As the catalyst mass fraction increases up to 0.1 (0.2 for LDPE + ZSM-5 mixture), the saturation is attained, and further addition of the catalyst has no effect. The heat of combustion of pyrolysis volatiles does not reveal a definitive dependence on the catalyst mass fraction, while in some cases the width of pyrolysis temperature interval as well as the char yield are affected. Decomposition of the remaining polymers in presence of ZSM-5 or MgO is either catalyzed rather weakly or even inhibited such as that in PS + ZSM-5 mixture. Among the polymers examined, PC turns out to be the only polymer that is considerably catalyzed by MgO. For the mixtures in which significant catalytic effect was detected, the formal kinetic models have been derived from the microscale measurements and shown to replicate the MCC data at different heating rates. These polymers, both individually and mixed with the catalyst, are often characterized by the non-monotonic conversion function which cannot be approximated by the n-th order reaction model.

Solvent-free carbon self-deposition of non-polymeric resin-based precursor toward N-doped porous carbon

Design and engineering of low-cost and high-efficiency functional carbonaceous electrode materials for supercapacitor has attracted increasing interest in energy storage. Herein, N-doped porous carbon block (N-PCB) was prepared via self-deposition of pyrolysis gas derived from directly degradation of typical resin monomer 3-aminophenol (AP) under the assistance of ZSM-5. In this monomer self-deposition approach, the rich pore channels of ZSM-5 promote the capture and deposition of pyrolysis gas from AP on ZSM-5 and the acidic surface of ZSM-5 catalyzes the pyrolysis gas conversion to carbon. This method realizes conversion of AP to porous carbonaceous material simply by grinding of AP and ZSM-5 mixture followed by routine pyrolysis treatment, without utilization of solvent and polymerization of resin, which simplifies the operation process and enhances the environmental friendliness. The prepared N-PCB replicates the bulk morphology of ZSM-5 and has a high specific surface area and a certain of nitrogen content, which provides favorable conditions for improving electrochemical performance.

RETRACTED ARTICLE: Study on Methylation of Naphthalene with Methanol over ZSM-5 (core)/SAPO-11(shell) Composite Molecular Sieve

ZSM-5 (core)/SAPO-11 (shell) composite molecular sieve was synthesized by the hydrothermal method in order to combine the advantages of ZSM-5 and SAPO-11 materials for the methylation of naphthalene with methanol. For comparison, the catalytic performance of mechanical mixture of ZSM-5 and SAPO-11 was also evaluated. The characterization results proved that ZSM-5/SAPO-11 composite has a core-shell structure. The pore size of the composite was between that of ZSM-5 and SAPO-11. The composite had fewer acid sites than ZSM-5 and mechanical mixture, but more acid sites than SAPO-11. The experimental results indicated that the composite exhibited good catalytic performance in the methylation of naphthalene with methanol.

Facile synthesis and catalytic applications of micro-mesoporous molecular sieve ZK-1

A micro-mesoporous molecular sieve ZK-1 was synthesized at 170 °C by a facile one-step hydrothermal method. The structure of ZK-1 can be controlled by the crystallization time. ZK-1(I), the KIT-1 containing ZSM-5 building units in the pore walls, is formed during 2–6 h. ZK-1(II), A mixture of ZSM-5 and KIT-1, is formed after 8 h. The framework structure, porosity, morphology and acidity of the obtained materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Transmission electron microscopy, N2 adsorption, X-ray fluorescence, NH3-temperature programmed desorption and 27Al Magic angle spinning NMR spectroscopy. The samples exhibit good steam stability and better catalytic performances in the isomerization of o-ethyltoluene than KIT-1, suggesting their promising applications in the conversion of large molecules.