NEW JOURNAL OF CHEMISTRY
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2019
·Vol. 43
·期 20
·7725-7732
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IF 3.069
Yun Hao,Ying-juan Hao,Jie Ren,Biao Wu,Xiao-jing Wang,Dishun Zhao,Fa-tang Li
In this work, N-methyl-2-pyrrolidonium (NMP) was acidized using hydrochloric acid to obtain [Hnmp]Cl first, which was then reacted with FeCl3 to prepare a series of inexpensive tunable [Hnmp]Cl·xFeCl3 (x = 0.2–2.0) ionic liquids (ILs) for the extractive and oxidative desulfurization of model oils. The Lewis acidities of these ILs were tested by the Fourier transform infrared (FT-IR) method, which indicated that when the x value of [Hnmp]Cl·xFeCl3 was above 1.0, the ILs exhibited Lewis acidity. The extraction results showed that the acidification of NMP reduced its dissolubility ability toward dibenzothiophene (DBT) and its Lewis acidity played a determining role in extractive desulfurization. In the catalytic oxidation removal process of the DBT model oil in the presence of H2O2, electron paramagnetic resonance (EPR) and scavenger experiments showed that the hydroxyl radical (˙OH) plays a key role and the superoxide anion radical (O2˙−) has a minor function. [Hnmp]Cl·1.5FeCl3 IL showed excellent recycling performance, which was due to its high dissolving capacity (23 700 ppm) for dibenzothiophene-sulfone (DBTO2).
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SEPARATION AND PURIFICATION TECHNOLOGY
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2019
·
IF 5.107
Xiaolong Han,Hexiang Sun,Liangliang Liu,Yuqi Wang,Gaohong He,Jiding Li
Incorporation of MOF particles into polymer matrix is an effective approach to prepare mixed matrix membranes (MMMs) with high selectivity and high permeability for pervaporation. In this article, regularly distributed CPO-Z7-Ni particles filled polydimethylsiloxane (PDMS) MMMs were prepared and used for pervaporation desulfurization. Benefiting from well-defined pore structures, high surface area, good compatibility with PDMS matrix and excellent thiophene adsorption capacity of the prepared CPO-27-Ni particles, both total flux and sulfur enrichment factor of the CPO-27-Ni/PDMS MMMs were remarkably increased. When the loading of CPO-27-Ni was 6 wt%, the optimal pervaporation performance was achieved with a flux of 5.92 kg/(m 2 ·h) and an enrichment factor of 4.05. These increased by 68.7% and 23.7% versus pristine PDMS membrane, respectively. It is proved that the incorporation of CPO-27-Ni particles into PDMS matrix can overcome the “trade-off” phenomenon between flux and sulfur enrichment factor, which is very important for pervaporation desulfurization.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
·
IF 3.375
Ye Zhang,Zhongyi Jiang,Jing Song,Jian Song,Fusheng Pan,Peng Zhang,Xingzhong Cao
Polymeric dense membranes for separating molecules with similar properties in liquid mixture according to solution-diffusion mechanisms are often constrained by trade-off effects. Integrating a facilitated transport mechanism and a sieving mechanism into membranes is a preferred approach to address this issue. Herein, amine-functionalized titanium-based metal–organic frameworks (NH2-MIL-125(Ti)) immobilized with Ag+, Ag+@NH2-MIL-125(Ti), was synthesized and hybrid membranes were fabricated for pervaporative desulfurization. The immobilized Ag+ can form reversible π-complexation toward thiophene and achieve thiophene-selectivity transport via a facilitated transport mechanism; meanwhile, Ag+ can decrease the effective pore size of the MOFs to elevate the diffusion selectivity of thiophene via a sieving mechanism. Accordingly, the resulting Pebax membranes with 1.0 wt % Ag+@NH2-MIL-125(Ti) exhibit a permeation flux of 22.11 kg/(m2 h) and an enrichment factor of 5.92. Furthermore, the hybrid membranes display increased thermostability and antiswelling properties by the incorporation of Ag+@NH2-MIL-125(Ti). This study proposes a strategy for the rational design of MOFs as nanofillers and endow the membranes with superior separation performance by integrating multiple transport mechanisms.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2019
·
IF 5.107
Yuhao Zhang,Hui Wang,Liang Zhao,Jinsen Gao,Chunming Xu
The performance of dimethyl sulfoxide (DMSO) solvent in separating olefins from aromatics and thiophene sulfides was evaluated through a series of ternary liquid-liquid equilibrium (LLE) experiments at 101.325 kPa and 303.15 K. The influences of the structures of olefins, aromatics, and thiophene sulfides on the separation efficiency were analyzed. Normal 1-hexene and isomer 2,4,4-trimethyl-1-pentene were easily separated from aromatics or thiophene sulfides, which only contain aromatic ring structures, such as benzene and thiophene. The reason is that the induced dipole on the aromatic ring structure introduced by the DMSO solvent significantly improved the polarity of aromatics and thiophene sulfide molecules, thereby enhancing the interaction with the ring structure. In addition, olefins were easier to separate from thiophene sulfides than from aromatics. The olefin separation factor of separating 2,4,4-trimethyl-1-pentene from thiophene was three times greater than that of separating the same olefin from benzene. The binary parameters between DMSO and olefins, aromatics, and thiophene sulfides for NRTL and UNIQUAC models were obtained through ternary LLE experiments. The maximum value of the root-mean-square deviation of the simulated compositions of phases compared with experimental data was 0.0052 in the two adopted models. Hence, the regressed binary parameters could efficiently describe the experimental LLE process. On the basis of the obtained binary parameters, the NRTL and UNIQUAC models are suitable for predicting the performance of olefin separation from fluid catalytic cracking naphtha. However, the NRTL model is more precise than the UNIQUAC model.
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APPLIED CATALYSIS A-GENERAL
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2019
·
IF 4.63
Aili Liu,Mingyuan Zhu,Bin Dai
The catalyst SnO 2 was prepared by a precipitation method, and then aged and calcined at the optimal temperature of 673 K. The reaction conditions were optimized and the oxidation desulfurization efficiency of the obtained catalyst were evaluated. The sulfur removal rate was 99.8% at the optimum reaction conditions of 0.08 g catalyst, 333 K, O/S = 10, 2 h. The catalytic site in the ODS process of the SnO 2 catalyst may be Sn 4+ /Sn 2+ Lewis acids. Furthermore, no significant catalytic performance decrease was observed over 14 reuse cycles. The excellent activity and reusability of the catalyst was attributed to the beneficial effects upon specific surface area and acidic-site strength of the appropriate heat treatment temperature.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Fazle Subhan,Sobia Aslam,Zifeng Yan,Ayaz Ahmad,U.J. Etim,Muhammad Naeem,Liu Zhen,Muhammad Ikram,Muhammad Yaseen
Lanthanum based adsorbents are promising in adsorptive desulfurization due to high activity. The dispersion degree of La 2 O 3 impacts desulfurization performance directly, and the development of an efficient strategy for La 2 O 3 dispersion still remained challenge. Herein, for the first time confined spaces and silanols of as-synthesized SBA-15 were used for dispersion of La 2 O 3 over mesoporous silica. The La(NO 3 ) 3 precursor is directly introduced into the confined spaces between silica walls and template of as-synthesized SAB-15 by solid state dispersion (SSD) strategy. The SSD strategy assists the formation of small sized La 2 O 3 with excellent dispersion after La precursor decomposition by the combined action of confined spaces and silanols. We also demonstrated that up to 20 wt% La 2 O 3 can be highly dispersed over as-synthesized SBA-15 (LaAS-20). Our investigations show that well-dispersion of La 2 O 3 correspond to high desulfurization activity for fuels, and the amount of thiophene captured can reach 0.12 mmol of S/g over LaAS-20, which is better than that over LaCS-20 and other La-doped reported sorbents. Furthermore, LaAS-20 adsorbent showed good stability and regeneration ability, and has potential applications to be applied in adsorptive desulfurization technology.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2019
·
IF 2.298
Wenliang Cui,Jilong Wang,Yueyang Xu,Zijia Cao,Yongping Zeng
Faujasite (FAU) zeolites with low Si/Al ratios (e.g., X-type zeolites) have much more exchangeable cation sites than those with high Si/Al ratios (Y-type zeolites) for Cu(I), which could improve the adsorption performance via π-complexation. However, the structure of Cu-exchanged X-type zeolites was unstable during autoreduction at high temperatures as reported [Takahashi; et. al., Ind. Eng. Chem. Res., 2002, 41, 2487−2496]. Here, we proposed a scheme of Cu-exchanged X-type zeolites in copper–ammonia solution to improve the stability of the zeolite structure during autoreduction. Therefore, it makes us be able to study the adsorption properties of thiophenic compounds in Cu(I)-exchanged FAU zeolites from low to high Si/Al ratios. The modified zeolites were characterized by X-ray diffraction, high-resolution transmission electron microscopy, inductively coupled plasma spectroscopy, X-ray fluorescence, and Brunauer–Emmett–Teller analysis and tested by adsorption desulfurization experiments in model fuels. The results indicate that the modified zeolites with various Si/Al ratios show different adsorption properties for thiophene and benzothiophene. The adsorption capacity for thiophene decreased in the order Cu(I)Y-5.30 > Cu(I)X-1.23 > Cu(I)Y-2.30. For benzothiophene, the adsorption capacity decreased in the order Cu(I)Y-2.30 > Cu(I)Y-5.30 > Cu(I)X-1.23.
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JOURNAL OF HAZARDOUS MATERIALS
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2019
·
IF 7.65
Xiao-Lu Sun,Zan Liu,Zhi-Lin Cheng
The novel nitrogen-doped porous carbon nanofibers film (PAN-CNFs) had been successfully prepared by electrospinning with polyacrylonitrile as carbon precursor after calcination under N 2 atmosphere. The structure and physical properties of PAN-CNFs were determined by a series of characterizations. The results showed that the PAN-CNFs-800 have the higher N content (10.02 wt.%), larger surface area (354.327 m 2 /g) and optional V mic /V Total (28.14 %). The adsorption desulphurization was examined by thiophene (TH) simulated oil. The experimental results demonstrated that the PAN-CNFs were the desirable adsorption materials as alternative candidate in present adsorption technique. Furthermore, the pseudo order kinetics and adsorption isotherm of the PAN-CNFs-800 was intensive studied, which exhibited good adsorptive capacity for thiophene (TH) reached 113.33 mg/L according to the Langmuir isotherm model and maintained promising recycling reusing performance. The adsorption mechanism was proposed by these models, which should be attributed to the cooperating effect of the proper pore structure and the π-π complexation interactions.
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PubMed
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CLAYS AND CLAY MINERALS
·
2019
·Vol. 67
·期 4
·325-333
·
IF 1.835
Guo Yu-Hua,Pan Guo-Xiang,Xu Min-Hong,Wu Tao,Wang Yong-Ya
Adsorption desulfurization is a potential new method for deep desulfurization of fuel oil. The development of adsorbents with high adsorption capacity and selectivity is the core of deep adsorption desulfurization. The adsorption behavior of thiophene in MCM-41 mesoporous materials modified by various metal ions was studied in order to understand the adsorption desulfurization process of molecular sieves. The Fe-, Co-, and Zn-modified MCM-41 materials were prepared using a one-step in situ hydrothermal synthesis method. The modified MCM-41 molecular sieves maintained the mesoporous structure, and the metal ions had specific dispersion on the surface of the molecular sieves. Adsorption of thiophene on the surfaces of molecular sieves had both physical and chemical characteristics. The adsorption desulfurization performance of the modified molecular sieve was superior to that of the pure silica molecular sieve. In the simulated gasoline with sulfur content of 220 μg/g, when the amount of adsorbent used was 100 mg, the adsorptive desulfurization performance tended to be in equilibrium, and the optimum adsorption temperature was 30°C. Fe-MCM-41 and MCM-41 molecular sieves reached adsorption equilibrium after ~60 min, but the desulfurization rate of Co-MCM-41 and Zn-MCM-41 still increased slightly. The kinetic simulation results indicated that the pseudo-second-order kinetics adsorption model described well the adsorption process of thiophene on molecular sieves. The molecular sieve Fe-MCM-41 had the best desulfurization performance with an equilibrium adsorption capacity of 14.02 mg/g and the desulfurization rate was ~90%.
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FUEL
·
2018
·
IF 4.908
Honghua Zhang,Hongguo Tang,Jiakuo Xu,Yajing Li,Zhiqiang Yang,Ruixia Liu,Suojiang Zhang,Yanji Wang
The aromatic-compound additive in sulfuric acid (H 2 SO 4 ) was found to promote isobutane/butene alkylation significantly. The selectivity of isooctane (C 8 ) and the alkylate research octane number increased by 23.46% and 5.09, respectively, when thiophene was added to H 2 SO 4 , especially. The proportion of trimethylpentanes can be improved from 58.57% to 84.58%, and the ratio of trimethylpentanes to dimethylhexanes was doubled, compared with that in the presence of H 2 SO 4 alone. The improved performance in the presence of thiophene additive in H 2 SO 4 is attributed to the improvement in carbenium-ion stability and the acceleration of hydrogen proton release, because of the existence of electron-rich π-bond compounds, and the substitution of thiophene in the alpha site by the sulfonic group and isobutane/butene. Reaction parameters such as reaction temperature, reaction time, stirring speed, feed rate, and acid/hydrocarbon volumetric ratio were also investigated in detail. The synergetic mechanism of thiophene-H 2 SO 4 on isobutane/butene alkylation was also speculated.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2018
·
IF 3.927
Yimeng Song,Donghui Yang,Shengnan Yu,Xinsheng Teng,Ze Chang,Fusheng Pan,Xianhe Bu,Zhongyi Jiang,Baoyi Wang,Sheng Wang,Xingzhong Cao
Tailoring the interface between the polymer matrix and filler to probe the structure-performance relationship is one of the critical research issues in hybrid membranes. In this study, metal organic framework (MOF) incorporated hybrid membranes are fabricated with polydimethylsiloxane (PDMS) as the matrix and Cu(II) loaded UiO-67-bpydc (bpydc refers to 2,2′-bipyridine-5,5′-dicarboxylic acid) as the filler, which are utilized for removing thiophene from model gasoline. The structure-performance relationship of the resultant membranes was investigated. The flux of the hybrid membrane shows a remarkable increase while avoiding obvious loss of selectivity. The loading of Cu(II) onto UiO-67-bpydc effectively tailors the interface between the polymer matrix and filler, which enhances the membrane separation performance. This study may offer a new example for designing MOF-based hybrid membranes towards efficient molecular separation.
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RSC Advances
·
2018
·Vol. 8
·期 69
·39641-39649
·
IF 2.936
Hui Li,Zhen Cao,Xiaolin Cao,Zejun Jiang,A. M. Abd El-Aty,Yan Qi,Hua Shao,Fen Jin,Lufei Zheng,Jing Wang
Two types of magnetic microspheres (Fe3O4@MIL-100 and Fe3O4@SiO2@polythiophene) were prepared and characterized as mixed sorbents for magnetic solid-phase extraction (MSPE) of six phthalic acid esters (PAEs), including dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di-2-ethylhexyl phthalate (DEHP), and di-n-octyl phthalate (DnOP) from water samples prior to gas chromatography-mass spectrometry (GC-MS) analysis. The synthetic magnetic nanocomposites exhibited good repeatability and chemical stability, and improved extraction efficiency for the tested PAEs. The mixture of the two types of nanoparticles substantially improved the extraction efficiency of both DMP and DEP. The key parameters affecting the extraction efficiency, such as the type and the amount of sorbent, eluent (desorption solvent), adsorption and desorption time, pH of sample solution, and sample volume, were investigated and optimized, respectively. Under optimized conditions, the developed method showed satisfactory linearity in the range of 5–5000 μg L−1 with coefficients of determination (R2) > 0.9935. The method detection limits (MDLs) and limits of quantitation (LOQs) were between 0.35–0.91 μg L−1 and 1.1–2.9 μg L−1, respectively. At three fortification levels (1.0, 10.0, and 50.0 μg L−1), the mean recoveries ranged from 76.9–109.1% with favorable relative standard deviations (RSDs) < 9%. The feasibility of the method was evaluated by analysis of water samples from various sources (tap, drinking, and mineral water). The results show that the developed method is suitable for determination of trace level PAEs in water samples.
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