Research Article Cite This: ACS Sustainable Chem. Eng. 2018, 6, 15858−15866
pubs.acs.org/journal/ascecg
Deep Oxidative Desulfurization of Fuel Catalyzed by Modified Heteropolyacid: The Comparison Performance of Three Kinds of Ionic Liquids Si-Wen Li,† Rui-Min Gao,‡ and Jian-she Zhao*,† †
Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Material Science, Northwest University, Xi’an, Shaanxi 710127, China ‡ Research Institute of Shaanxi Yanchang Petroleum Group Corp., Ltd., Xi’an 710075, China ACS Sustainable Chem. Eng. 2018.6:15858-15866. Downloaded from pubs.acs.org by UNIV OF WINNIPEG on 12/21/18. For personal use only.
S Supporting Information *
ABSTRACT: Three kinds of ionic-liquid (IL)-modified heteropolyacids, with one N atom, two N atoms, and cyclic N type of quaternary ammonium salt, were synthesized successfully (S-POM, D-POM, and C-POM), and the relative heterogeneous catalysts system for oxidative desulfurization was obtained from simple one-pot hydrothermal reaction and modified heteropolyacids in the pores of MCM-41 after MOF-199 template self-assembly (S/D/C-POM@MOF@ MCM-41). These as-designed samples were characterized via XRD, XPS, TEM, BET analysis, and so on. Results showed that the S/D/C-POM active species could be successfully immobilized into the mesoporous materials and all retained their Keggin structure. C-PMM carried out excellent performance for oxidesulfurization. Under optimal conditions, the rate of DBT removal could reach up to 100% in 90 min, and the catalyst was reused more than 10 times with nearly no significant reduction on catalytic activity. The various sulfur compounds also had an important effect on catalytic performance, which was also investigated and showed the competitive adsorption oxidation with the BT and 4,6-DMDBT in real oils from the DFT calculation. According to the real diesel oxidative desulfurization, it was found that nearly all the sulfur compounds could be completely removed. Meanwhile, a possible mechanism is also studied under the calculation evaluation. KEYWORDS: Ionic-liquid-modified heteropolyacid, Metal−organic framework, MCM-41 molecular sieve, Real diesel, Oxidative desulfurization
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INTRODUCTION Energy production has been increasingly related with environmental issues regarding pollution. Fossil fuels are the majority, more than 82%, of the world’s energy supply.1−3 Petroleum, containing plenty of hydrocarbons with varying small molecular weights and large organic compounds, provides half of fossil oil.4 It is unfortunate that petroleum-based liquid fuel contains various sulfur molecules, having large negative effects on industry and environment development. Alternatively, upon combustion, the formed SOx contributed to air pollution, causing acid rain as well as destroying aftertreatment devices.5−7 These hazards lead to the increasingly stringent limits for fuels including the lowest sulfur level. Thus, desulfurized means on refractory S-containing compounds, mainly for dibenzothiophene (DBT) and its derivatives, must be updated.8−10 However, it is hard to remove them by the conventional process, hydrodesulfurization (HDS), because of the severe temperature and pressure conditions, as well as the high hydrogen consumption or longer using time.11,12 Hence, there is an urgent need for supplementary or alternative © 2018 American Chemical Society
energy-efficient and cost-effective technologies for desulfurization.13,14 Oxidative desulfurization (ODS) may be a good choose, showing great promises for the mild operation conditions (
