abstract
An effective and sustainable oxidative desulfurization process for treating a multicomponent model fuel was successfully developed using as a heterogeneous catalyst a composite material containing as an active center the europium Lindqvist [Eu(W5O18)(2)](9-) (abbreviated as EuW10) encapsulated into the nanoporous ZIF-8 (zeolitic imidazolate framework) support. The EuW10@ZIF-8 composite was obtained through an impregnation procedure, and its successful preparation was confirmed by various characterization techniques (FT-IR, XRD, SEM/EDS, ICP-OES). The catalytic activity of the composite and the isolated EuW10 was evaluated in the desulfurization of a multicomponent model fuel containing dibenzothiophene derivatives (DBT, 4-MDBT and 4,6-DMDBT) with a total sulfur concentration of 1500 ppm. Oxidative desulfurization was performed using an ionic liquid as extraction solvent and aqueous hydrogen peroxide as oxidant. The catalytic results showed a remarkable desulfurization performance, with 99.5 and 94.7% sulfur removal in the first 180 min, for the homogeneous active center EuW10 and the heterogeneous EuW10@ZIF-8 catalysts, respectively. Furthermore, the stability of the nanocomposite catalyst was investigated by reusing and recycling processes. A superior retention of catalyst activity in consecutive desulfurization cycles was observed in the recycling studies when compared with the reusing experiments. Nevertheless, the nanostructure of ZIF-8 incorporating the active POM (polyoxometalate) was shown to be highly suitable for guaranteeing the absence of POM leaching, although structural modification was found for ZIF-8 after catalytic use that did not influenced catalytic performance.
keywords
EFFICIENT HETEROGENEOUS CATALYST; DEEP OXIDATIVE DESULFURIZATION; IONIC-LIQUIDS; POLYOXOMETALATE; MODEL; DIESEL; ZIF-8; POLYOXOMOLYBDATE; EXTRACTION; OIL
subject category
Chemistry; Science & Technology - Other Topics; Materials Science; Physics
authors
Fernandes, S; Flores, D; Silva, D; Santos-Vieira, I; Mirante, F; Granadeiro, CM; Balula, SS
our authors
Carlos Miguel Cardeal Enes Granadeiro
Post-Doc Fellowship
Isabel Cristina Maia da Silva Santos Vieira
Junior Researcheracknowledgements
This research work received financial support from Portuguese national funds (FCT/MCTES, Fundacao para a Ciencia e a Tecnologia and Ministerio da Ciencia, Tecnologia e Ensino Superior) through the strategic project REQUIMTE-LAQV (FCT, Ref. LAQV, REQUIMTE (POCI-01-0145FEDER-007265, UID/QUI/50006/2013)], and UIDB/50011/2020 and UIDP/50011/2020 (for CICECO). Parts of this work were performed with funds from the European Union (FEDER funds through COM-PETE POCI-01-0145-FEDER-031983.