(Zn, Ni, Cu)-BTC Functionalized with Phosphotungstic Acid for

Subscriber access provided by University of Groningen

Article

(Zn, Ni, Cu)-BTC Functionalized with Phosphotungstic Acid for Adsorptive Desulfurization in the Presence of Benzene and Ketone Wei Dai, Ning Tian, Congmin Liu, Le Yu, Qing Liu, Na Ma, and Yuexing Zhao Energy Fuels, Just Accepted Manuscript • DOI: 10.1021/acs.energyfuels.7b02851 • Publication Date (Web): 28 Nov 2017 Downloaded from http://pubs.acs.org on November 29, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

Energy & Fuels is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

(Zn, Ni, Cu)-BTC Functionalized with Phosphotungstic Acid for Adsorptive Desulfurization in the Presence of Benzene and Ketone Wei Dai,*,† Ning Tian,† Congmin Liu,‡ Le Yu,† Qing Liu,† Na Ma,§ and Yuexing Zhao† †

Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal

University, Jinhua 321004, People’s Republic of China ‡

National Institute of Clean-and-Low-Carbon Energy, Beijing 102211, People’s Republic of China

§

College of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004,

People’s Republic of China

ABSTRACT: A novel composite adsorbent, PTA@(Zn, Ni, Cu)-BTC, was prepared by (Zn, Ni, Cu)-BTC doped with different amount of phosphotungstic acid (PTA) using an impregnation method. Apparatus like nitrogen adsorption-desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), inductively coupled plasma optical emission spectroscopy (ICP-OES), and NH3-temperature programed desorption (NH3-TPD) are employed to characterize our obtained adsorbents. The adsorption properties of as-prepared adsorbents for the dibenzothiophene (DBT) were evaluated by means of fixed-bed breakthrough experiments. Unlike conventional MOFs (metal-organic frameworks), the PTA@(Zn, Ni, Cu)-BTC exhibited high DBT selectivity adsorption performs with a superior uptake capacity compared with those previously reported in the literatures. Additionally, PTA@(Zn, Ni, Cu)-BTC showed a remarkable stability in the presence of benzene and acetone, maintaining about 95 % initial uptake capacity after eight

ACS Paragon Plus Environment

Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

regeneration procedures. PTA@(Zn, Ni, Cu)-BTC is confirmed to be a hopeful material for DBT capture toward deep desulfurization. Key words: Dibenzothiophene; (Zn, Ni, Cu)-BTC; Adsorption, Phosphotungstic acid; Acetone 1. INTRODUCTION Given the current austere situations of air pollution caused by car exhaust and the pessimistic obstacles put by the deactivation of auto-catalysts, a demand to decline the hazards generated by the organosulfur compounds in fuels (gasoline and diesel oil) is rather urgent.1 Hydro-desulfurization (HDS), an existing industrialized method, is highly effective in removing simple sulfur compounds such as mercaptan and thioether, etc in fuels.1,2 Unfortunately, though efficient as HDS is, it’s unreliable to eliminate aromatics in thiophenic sulfides such as DBT because of higher hydrogenation activity of olefins and aromatics.2-4 At the same time, it’s interesting to note that as one of the non-HDS technologies, adsorption is so far regarded as a promising technology when considering its economical efficiency and easily available technical conditions.5 In addition, lots of oxygen-containing compounds (OCCs) are proved to be beneficial in decreasing the discharge of certain matters from fuel engines.6 Nevertheless, since oxygen and sulfur are listed as cognate elements in the periodic table of elements, sharing similar physical and chemical properties, there might be a competitive adsorption onto adsorbents between oxygen and sulfur compounds, which would lead to lower adsorption desulfurization efficiency.7,8 Thus, proper adsorbents with desirable performance even in the existence of aromatics (e.g.


Page 2 of 30

Page 3 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

benzene) and OCCs (e.g. acetone) need to be developed. Recently, MOFs with open metal sites, belonging to a developing class of materials with various exceptional potential interactions inside the pores, have been successfully applied to ultra deep desulfurization.9 Numerous investigations in this field have been done to analyze the performance of MOFs,9-13 for example, Khan et al. by means of three analogous MIL-53(Cr/Al/V) demonstrated that the removal of thiophenic compounds are greatly promoted by the central metal ion of MOFs.10 Based on analysis, they found that the sulfur uptake capacities are caused by the different metal sites of the MOFs. Meanwhile, they observed that Cu+-doped MIL-100-Fe is an enhanced adsorption for benzothiophene and further inquired into the advantageous effect of π-complex formation.11 Cychosz et al.12 found that due to its high selectivity and capacities, MOFs preceded other adsorbents like zeolites or activated carbons in the adsorption of DBT and 4,6-dimethyldibenzothiophene in oil models. In our previous works,13,14 a series of MOFs consisting of altered central metals (Cu2+, Ni2+and Zn2+) while the same H3BTC organic linker (BTC is benzoic acid radical) have been successfully synthesized. Attribute to synergistic ability and open metal sites, the three-metal (Zn, Ni, Cu)-BTC exhibited the highest sulfur capacity, which is advanced to Cu-BTC and bimetallic (Zn, Cu)-BTC. Still, those MOFs mentioned above are worthless in the existence of OCCs, which renders the desulfurization capacity seriously reduced. Hence, there is a calling for a modification technique to be developed to improve the desulfurization capacity and the durability of the MOFs materials.


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Along with the central metal sites or surface functionalization, for creating a better performance, modification like introducing surface acidity into MOFs has been carried out and Heropolyacids (HPAs) play a vital role in this fields.15,16 These HPAs can be loaded inside the pores of the MOFs, which necessarily makes them immobilized inside the MOFs cages.17 Moreover, as acidic functional moieties, HPAs will not go out during the sorption process. Among all kinds of HPAs, the phosphotungstic acid (PTA) is one of the most outstanding heteropoly acids.18,19 When it comes to the classification of acids, its useful to consult soft acid-base and Pearson’s hard concept. From the perspective of Pearson, bases can be divided into two categories, the non-polarizable and the polarizable which are defined as “hard” and “soft”, respectively. That is, acids that interact strongly with soft bases and hard are correspondingly called hard and soft acids. Based on this concept, sulfur compounds bases (e.g. DBT) exhibiting the characteristic of Lewis base with lone pair electrons, are relatively verge on soft. Thus, soft Lewis acids, such as heteropolyacids might strongly attract soft DBT bases.1,13,18 On the basis of our previous works,13,14 we will try to explore whether higher adsorption performance could be obtained by immobilization of PTA in the pore structure of the three-metal MOFs ((Zn, Ni, Cu)-BTC) in this work. Apart from this, its’ apparent that scarce published works dealing with the study of MOFs durability in a fixed-bed column have been done. So in order to probing a new view in this field, we are aim to provide experimental evidence of this type of MOFs performance using different model fuels. To achieve the goal, PTA@(Zn, Ni, Cu)-BTC was prepared by


Page 4 of 30

Page 5 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

modification of (Zn, Ni, Cu)-BTC with diverse amounts of PTA by means of impregnation technique. Three commercial model fuels were used in this work. The adsorption desulfurization performance of the novel PTA@(Zn, Ni, Cu)-BTC material at 25 oC and atmospheric pressure was investigated by fixed-bed tests. 2.

EXPERIMENTAL SECTION

2.1. Chemicals. The chemicals include benzene tricarboxylic acid (H3BTC, 98%), zinc nitrate hexahydrate (Zn(NO3)2·6H2O,≥99%), nickel nitrate hydrate (Ni(NO3)2·6H2O, ≥ 99%), cupric nitrate hydrate (Cu(NO3)2·3H2O, ≥99% ) DBT (≥99%), benzene (≥ 99%), octane ( ≥ 99%), acetone (chromatographic purity, ≥ 99.9%) and phosphotungstic acid (≥99%), which were all supplied by Sigma-Aldrich Chemical Co, Ltd. All the chemicals admitted in these experiments were used without being further purified. 2.2. MOFs Synthesis The (Zn, Ni, Cu)-BTC material was conducted through the same method as in a literature procedure.13,14 Briefly, a mixture of H3BTC (2.0 mmol), (Zn(NO3)2·6H2O, Ni(NO3)2·6H2O and Cu(NO3)2·3H2O, with the molar ratio of 1:1:2; 3.65 mmol in total) was dissolved into a 24 mL mixture of 1:1 (wt./wt.) water and ethanol, followed by the magnetic agitation of 10 min. After that the precursor was obtained and in a preheated electric oven, it was loaded onto a Teflon autoclave and be treated at 140 oC for 1.5 h. The autoclave was cooled down to 25 oC and a water-ethanol mixture was next used to work off any unreacted H3BTC from the blue powder. The purified


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

product was obtained after filtration and dried at 150 oC for 5 h. Afterwards, PTA was loaded into Cu-BTC according to the previous work.20 PTA (H3PO412WO3·xH2O) and 0.1 g of (Zn, Ni, Cu)-BTC (The mass ratio of W and Cu is 1:1) were put in 10 mL water. Mechanically stirring the mixture solution for 5 h at room temperature (25 oC) and then filtrate the suspension to get the solids. The obtained solid powder was designated as PTA(1.0)@(Zn, Ni, Cu)-BTC. Another two samples, PTA(0.5)@(Zn, Ni, Cu)-BTC and PTA(0.2)@(Zn, Ni, Cu)-BTC the W/Cu weight ratio of 0.5/1.0 and 0.2/1.0), were synthesized by referring to the coincident procedures. 2.3. MOFs Characterization N2 adsorption/desorption measurements were analyzed on an ASAP 2020 (physical adsorption instrument) at −196 oC. The N2 adsorption data from this instrument is very reproducible and the error span is ±1%. The pore size distribution was determined by employing the desorption branch of the N2 isotherm using the NLDFT (Nonlocal Density Functional Theory) method. A Hitachi S4800 electron microscope was used to determine the SEM images. The XRD (D2 Phaser, Bruker, CuKα radiation) was employed to have a good look of the samples’ crystal phase. ICP-OES (Thermo ICP-OES 6500) was in charge of the elemental analysis of the metal. A Nicolet Nexus 470 spectrometer was applied to recorded the FT-IR spectra with KBr pellet samples and a Thermo Electron TPD/R/O 1100 analyzer was operated to acquire the NH3-TPD data. 2.4. Dynamic Breakthrough Tests We used benzene to stand for the aromatic fuel (ARF) and n-octane for the aliphatic


Page 6 of 30

Page 7 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

fuel (ALF) to prepare three typical model fuels. The 80 wt% n-octane and 20 wt% benzene stands for the mixed fuel (MIF). DBT was dissolved in three types of fuels as the representatives of sulfur contaminants. The initial S-concentrations are 800 ppmw S for ALF, ARF and MIF, individually. The sulfur content was concluded by a GC-2100 (Shanghai Shengyu Hengping Co., Ltd.) gas chromatograph (GC) equipped with a flame photometric detector (FPD). The breakthrough curves of DBT onto the MOFs on the basis of effluent to influent concentrations ratio, C/Co, versus residence time were obtained by a down flow fixed column system. This system included a glass column column (8 mm internal diameter and 300 mm length), a constant flow pump (Hangzhou Nade Co., Ltd.), and custom sample collection system. The dynamic breakthrough tests were operated at 25 ◦C and atmospheric pressure. First of all, at the bottom of the column, the as-prepared MOFs was packed on a plastic sieve. Then after ALF, ARF and MIF model fuels (the density values of ALF, ARF and MIF are 0.6755, 0.8657 and 0.7112 g/mL, respectively) were mixed in a glass beaker, pumping the mixture into the column at a constant at volumetric flow rate of 1 cm3/min. Usually, it has different breakthrough and saturation point, which depends on several factors such as types of adsorbents, particle size, columns, etc.13,14 The breakthrough and saturation points are Ci/Co=0.01 and 0.99 in this work. The effluent samples were gotten at regular time intervals until Ci/Co reached unity or the concentration remained constant. All the sulfur uptake capacities were calculated by using equations21,22 (1) and (2): qb = (

vρxi ) × tb × 100% m

(1)


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

qs = (

vρxi ts c ) ∫ [1 − t ]dt × 100% 0 m ci

Page 8 of 30

(2)

Hereby, qs is the saturation adsorption capacity, %; qb is the breakthrough capacity, %; v is the flowrate of oil, cm3/min; ρ is the simulated fuel density, g/cm3; ci is the initial sulfur concentration, ppm; ct is the sulfur concentration of the simulated fuel flowing through the column at time t, ppm; tb is the breakthrough time, min; ts is the saturation time when ct/ci =1, min; m is the mass of adsorbent, g; xi is the sulfur concentration in the simulated fuels, %. Especially, the Veff (in the Fig. 7-12) is the effluent volume of ALF, ARF or MIF passing through a unit mass adsorbent in the column. The eff is the abbreviation of effluent.

3. RESULTS AND DISCUSSION 3.1. MOFs Characterization Being

presented

in

Table

S.I.1

and

Figure

1(A),

(B)

are

the

N2

adsorption-desorption curves, pore size distributions and aggregated textural data of all the MOFs, correspondingly. As you may expect from the graph, the isotherms of the (Zn, Ni, Cu)-BTC and its composites (PTA@(Zn, Ni, Cu)-BTC) samples are a combination of type I and IV13,14 (IUPAC classification) with a hysteresis loop at high relative pressure indicating both microporous and mesoporous domains. The existence of a high proportion of micropores in these adsorbents was implied by the sharp rise at the low pressure and the arise of mesoporous pores was positively conjectured from the H4 hysteresis loop emerges at P/Po of ∼0.4 which is ascribed to the crystallization process. Relative larger cavities can only be accessed via much smaller cavities that limit the diffusion of molecules with large sizes.13,23 Existence of mesopores in MOFs


Page 9 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

allows access of bulkier DBT to active adsorption sites and encourage mass transport which makes mesoporous favorable to the capture of adsorbates. According to the Fig.1(B), the pore sizes concentrated at two regimes with 0.5–1.4 nm (I) and 1.6–3.0 nm (II). In regime I, the pore volumes of MOFs decreased with an increasing in the amount of PTA. The same presentation also shown in regime II. From the Table S.I.1, it can be observed that the BET surface area of the (Zn, Ni, Cu)-BTC decreases with increasing of the PTA doping. All the materials prepared from PTA-loaded MOFs (PTA@(Zn, Ni, Cu)-BTCs) show lesser porosity than (Zn, Ni, Cu)-BTC even though the quantity of PTA loading inside the (Zn, Ni, Cu)-BTC did not have a significant influence on the porosities. The micropore and the total pore volumes also indicate a similar trend as that of the surface area. As shown in Figure 2, the XRD diffraction peaks of the as-synthesized (Zn, Ni, Cu)-BTC is coincide with the earlier works,13,14,23 indicating that hardly any difference exists among the bare (Zn, Ni, Cu)-BTC and the samples with the PTA doping. The similarity of the peak positions of the PTA@(Zn, Ni, Cu)-BTCs composites with that of the parent (Zn, Ni, Cu)-BTC illustrates that the formation of the composites’ crystal structure was not prevented by the incorporation of PTA. In addition, the chemical composition of (Zn, Ni, Cu)-BTC by ICP-OES was listed in Table S.I.2. ICP-OES analysis detected concentration of W in the PTA@(Zn, Ni, Cu)-BTC framework. Metal content of the composite adsorbent slightly decreases after doped PTA by impregnation technology. The SEM images in Figure 3 revealed that PTA@(Zn, Ni, Cu)-BTC material does


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

not have much different physical appearance from the virgin (Zn, Ni, Cu)-BTC. It demonstrated that the morpholgy of crystal structure, which has a regular octahedron with about 10~20 µm in width was not changed by the doping of PTA. Further information on the (Zn, Ni, Cu)-BTC and PTA(0.5)(Zn, Ni, Cu)-BTC is presented by FT-IR spectra in Figure 4. The characteristic vibration at 730 cm−1 might result from Cu–O stretching vibration, in which the oxygen atom was synchronized with Cu. Besides, a rather broad peak at 3400 cm−1 in the complex suggested that water molecules are loosely bound with Cu-BTC. The most notable indications of these peaks are the stretching VC=O, VC–O and bending O–H vibrational frequencies seen at 1645, 1374 and 1444 cm−1, respectively, specifying the presence of a carboxylic acid group. The spectrum of (Zn, Ni, Cu)-BTC matches well with Cu-BTC in the literatures.23,24 The bands at 827 and 985 cm−1 corresponded to the W-O-W vibrations and W-O stretching, in turn. Besides those bands, the bands at 1081 cm−1 clearly presented in both two samples are correlated with the P-O stretching in unsubstituted PTA and O-P-O vibration. Previous related studies proved the similar finding.19, 25-28 Figure 5 displays the TGA curves of (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples. Two types of MOFs have a similar curve shape, whose weight loss around 30 to 120 oC could be ascribed to the release of the moisture or other volatile solvent inside the cavities, respectively. And no obvious mass loss was observed from 120 to 300 oC, which indicated the as-prepared adsorbents could be heated under a stream of nitrogen below 300 oC. The sharp weight of PTA(0.5)@(Zn, Ni, Cu)-BTC


Page 10 of 30

Page 11 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

and (Zn, Ni, Cu)-BTC decreased about 50 and 60 % around 350 oC suggests the structure collapse of the MOFs. (Zn, Ni, Cu)-BTC sample might degrade to ZnO, NiO or CuO at temperatures higher than 600 oC. While PTA@/(Zn, Ni, Cu)-BTC might partially degrade to phosphorus-tungsten composite oxides except ZnO, NiO, or CuO. Thus, PTA@/(Zn, Ni, Cu)-BTC is more thermally stable than (Zn, Ni, Cu)-BTC, possibly due to alloy oxide effect in the structure. Similar results in the literatures can be found.13,14 NH3-TPD technology was conducted over the (Zn, Ni, Cu)-BTC and PTA@(Zn, Ni, Cu)-BTC. NH3-TPD profiles of the adsorbents are presented in Figure 6. The data of acid strengths are listed in Table S.I.3. On the basis of NH3 desorption temperature, the acid sites can be classified into weak (150–300 ◦C), medium (300–500 ◦C), and strong (500–650 ◦C) strength. We have detected the broad NH3-TPD peaks at the temperatures of 270 and 625 ◦C, signifying (Zn, Ni, Cu)-BTC and PTA@(Zn, Ni, Cu)-BTC have relatively weak and medium-strength acid sites, respectively. Apart from that, the total acidity of as-synthesized samples of PTA(0.2)@(Zn, Ni, Cu)-BTC, PTA(0.5)@(Zn, Ni, Cu)-BTC and PTA(1.0)@(Zn, Ni, Cu)-BTC was about 0.55, 0.61, and 0.82 mmol/g, respectively. It pointed out that, with the increase of PTA contents in the PTA@(Zn, Ni, Cu)-BTC sample, the total acidity of as-synthesized material was increased.

3.2. Breakthrough Curves Firstly, as seen in Figure 7, 8 and 9, the DBT adsorption curves of virgin (Zn, Ni, Cu)-BTC before and after doping with different amount PTA for ALF, ARF and MIF


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

were examined, separately. For all three simulated fuels, the adsorbed quantities of DBT by PTA@ (Zn, Ni, Cu)-BTCs are higher than the adsorbed quality by (Zn, Ni, Cu)-BTC sample. Unfortunately, the uptake capacities don’t proportionate to the doping number of PTA. The non-linear result may stem from the change in the composition and structure of domains on (Zn, Ni, Cu)-BTC, or the inaccessibility to the acid adsorption sites for partial domains. Secondly, PWA(0.5)@(Zn, Ni, Cu)-BTC exhibits better property than PWA(0.2)@(Zn, Ni, Cu)-BTC, which implies that the desulfurization function improves with the number of PTA doping. From these results, a distinctive advantageous interaction between PTA in (Zn, Ni, Cu)-BTC and DBT can be asserted. Yet, the doping of PTA on (Zn, Ni, Cu)-BTC will not be increased further due to the possibility for it to block the pore as well as fortifying the diffusion resistance during the mass transfer process. This, in reality, can reduce the number of accessible acid adsorption sites to unify the acid (PTA)-base (DBT) interaction, and in turn causing he base sorbent with higher PTA loading PTA(1.0)@(Zn, Ni, Cu)-BTC possesses a smaller DBT uptake capacity than PWA(0.5)@(Zn, Ni, Cu)-BTC. PTAs in (Zn, Ni, Cu)-BTC act as acidic centers toward the slightly basic DBT, resulting in a satisfactory interaction between PTA@(Zn, Ni, Cu)-BTC and DBT.25,26 The rising in uptake capacity with increasing content of PTA (Fig. 6-8) approves once again that PTAs can be favorable as active sites for DBT due to the acid (PTA)-base (DBT) interaction. Another point that should be noted is that, as the DBT capacity of Zn/Cu-BTC decreased, it has better adsorption performance for ALF than for ARF and the as-prepared MOFs still show better desulfurization performance than those


Page 12 of 30

Page 13 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

mentioned in existing work.14,21 The DBT uptake capacities of the as-prepared MOFs in this work are summarized in Table S.I.4, together with some other MOFs reported previously.14,21,27-29 Both breakthrough and saturation uptake capacities of the PTA(0.5)@(Zn, Ni, Cu)-BTC are comparatively higher than most of MOFs and the other adsorbents.14,21,27-29 Additionally, the PTA@(Zn, Ni, Cu)-BTC material present much stronger durability in desulfurization processes with the accompany of the OCCs such as acetone. The positive effect of OCCs on the adsorption of DBT over (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC were further investigated in ALF, ARF and MIF containing no acetone and 5% acetone, respectively (Figure 10-12). Owing to competitive adsorption between acetone and DBT, the breakthrough and saturation capacities for DBT adsorption from the ALF, ARF and MIF containing no acetone over (Zn, Ni, Cu)-BTC were (10.92%, 13.08%), (5.48%,7.11%) and (7.93%, 9.61%), correspondingly, showing an approximately 16%-ALF, 50%ARF and 13%-MIF surges compared with adding 5% acetone in the model fuels. The DBT breakthrough and saturation uptake capacities of PTA(0.5)@(Zn, Ni, Cu)-BTC in ALF, ARF and MIF containing 5% acetone were calculated to be (15.62%,18.71%), (10.41%,13.51%) and (10.31%,12.49%), which are quite close to the uptake capacities of the material in the origin fuel containing no acetone. This reveals that the virgin (Zn, Ni, Cu)-BTC poorly performed with the existence of oxygenates even though the sorbent exhibited positive result when deprived of acetone. In contrast, PTA(0.5)@(Zn, Ni, Cu)-BTC shown undistinguished performances in the absence of oxygenates but also


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

significantly resistance to acetone. Thus, by modifying with PTA, the influence of acetone on the sulfur uptake capacity of the (Zn, Ni, Cu)-BTC can be effectively eliminated. This might be majorly influenced by the increased density of acidic groups in the MOF surface as the porosities of the MOFs are not much altered from Table S.I.1. The phenomenon might be explained by polarity interactions and hydrogen bonding, since polar groups may experience attractive interactions with slightly polar adsorbates such as DBT and acidic functional groups of PTA, with the possibility of hydrogen bonding are positive to the resistance to oxygenates with polar acetone. Such finding is consistent with that those reported previously.28,29

3.3. Reusability of PTA@(Zn, Ni, Cu)-BTC After adsorption saturation, the PTA@(Zn, Ni, Cu)-BTC was submerged in methanol with magnetic stirring for 3 h, and then at 300 oC for 4 h with nitrogen sweeping in a quartz tube furnace. After five cycles regeneration, the DBT breakthrough curves of regenerated PTA(0.5)@(Zn, Ni, Cu)-BTC were then collected again with the simulated fuels. The results shown that the sulfur uptake capacities of the regenerated MOFs (recycled eight times) are ~95 % of the initial values (Figure 13), which is resulted from the not only the stability of the adsorbent in adsorption but also the regeneration conditions revealed from the saturation capacities of the regenerated PTA@(Zn, Ni, Cu)-BTC for DBT. The very minor loss of desulfurization efficiency of DBT is probably due to the leaching loss of the adsorbent. From the perspective of practical application, the nitrogen adsorption isotherms and XRD patterns were measured and compared. And the results tell that the pore volume and


Page 14 of 30

Page 15 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

surface area were well tallied and analogous with each other before and after dynamic adsorption experiment, which proves that material can be recycled several times through solvent washing without any significant reduction in its performance.

4. CONCLUSIONS Functionalized (Zn, Ni, Cu)-BTC sorbents with PTA loadings was synthesized to systematically study its adsorption performance for DBT from three sorts of model fuels in terms of breakthrough curves. These composite adsorbents are more effective for the preferential adsorption of DBT from solutions containing octane, benzene, and ketone than virgin (Zn, Ni, Cu)-BTC, and sulfur uptake capacities comparable to or preferable to those mentioned for other adsorbents have been achieved. The saturated MOFs can be regenerated with ethanol clean and nitrogen purging method. About 95 % of the sulfur uptake capacity was recovered after regeneration. The high sulfur capacity and good regeneration behavior indicate that PTA@(Zn, Ni, Cu)-BTC is an encouraging sorbent for deep desulfurization.

ASSOCIATED CONTENT

Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: Textural properties of (Zn, Ni, Cu)-BTC before and after loading PTA (Table S.I.1), chemical composition of (Zn, Ni, Cu)-BTC and PTA@(Zn, Ni, Cu)-BTC by ICP -OES (Table S.I.2), acidity of the (Zn, Ni, Cu)-BTC and PTA@(Zn, Ni, Cu)-BTC samples (Table S.I.3), and sulfur uptake capacity of different adsorbents at ambient


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

temperature and pressure (Table S.I.4).

AUTHOR INFORMATION

*,†E-mail: [email protected]. Fax: +86-579-82282325.Tel:+86-579-82282269.

ACKNOWLEDGMENTS We thank to the Zhejiang Provincial Natural Science Foundation of China under

Grant No. LY16B060002 and Open Research Fund of Key Laboratory of the Ministry of Education for Advanced Catalysis Materials and Zhejiang Key Laboratory for Reactive Chemistry on Solid Surfaces, Zhejiang Normal University

REFERENCES

(1) Khan, N. A.; Hasan, Z.; Jhung, S. H. Adsorptive Removal of Hazardous Materials Using Metal-Organic Frameworks (MOFs): A review. J. Hazard. Mater. 2013, 244–245, 444–456. (2) Khan, N. A.; Jhung, S. H. Remarkable Adsorption Capacity of CuCl2-Loaded Porous Vanadium Benzenedicarboxylate for Benzothiophene. Angew. Chem. Int. Ed. 2012, 51, 1198–1201. (3) Shi, Y.; Zhang, X.; Wang, L.; Liu, G. MOF-derived Porous Carbon for Adsorptive Desulfurization. AIChE J. 2014, 60, 2747–2751. (4) Ahmed, I.; Jhung, S. H. Adsorptive Desulfurization and Denitrogenation Using Metal-Organic Frameworks. J. Hazard. Mater. 2016, 301, 259–276. (5) Seredych, M.; Lison, J.; Jans, U.; Bandosz, T. J. Textural and Chemical Factors Affecting Adsorption Capacity of Activated Carbon in Highly Efficient Desulfurization of Diesel Fuel. Carbon 2009, 47, 2491–2500.


Page 16 of 30

Page 17 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

(6) Wang, Y.; Zhou, L. B.; Wang, H. W. Diesel Emission Improvements by the Use of Oxygenated DME/Diesel Blend Fuels. Atmos. Environ. 2006, 40, 2313–2320. (7) Xiao, J.; Song, C.; Ma, X.; Lit, Z. Effects of Aromatics, Diesel Additives, Nitrogen Compounds, and Moisture on Adsorptive Desulfurization of Diesel Fuel over Activated Carbon. Ind. Eng. Chem. Res. 2012, 51, 3436–3443. (8) Li, Y.; Yang, F. H.; Qi, G.; Yang, R. T. Effects of Oxygenates and Moisture on Adsorptive Desulfurization of Liquid Fuels with Cu(I)Y Zeolite. Catal. Today

2006, 116, 512–518. (9) Furukawa, H.; Cordova, K. E.; O’Keeffe, M.; Yaghi, O. M. The Chemistry and Applications of Metal-Organic Frameworks. Science 2013, 341, 974. (10) Khan, N. A.; Jun, J. W.; Jeong, J. H.; Jhung, S. H. Remarkable Adsorptive Performance of a Metal-Organic Framework, Vanadium-Benzenedicarboxylate (MIL-47), for Benzothiophene. Chem. Commun. 2011, 47, 1306–1308. (11) Khan, N. A.; Jhung, S. H. Low-Temperature Loading of Cu+ Species over Porous Metal-Organic Frameworks (MOFs) and Adsorptive Desulfurization with Cu+-Loaded MOFs. J. Hazard. Mater. 2012, 237–238, 180–185. (12) Cychosz, K. A.; Wong-Foy, A. G.; Matzger, A. J. Enabling Cleaner Fuels: Desulfurization by Adsorption to Microporous Coordination Polymers. J. Am. Chem. Soc. 2009, 131, 14538–14543. (13) Wang, T. T.; Fang, Y. Y.; Dai, W.; Hu, L. F.; Ma, N.; Yu, L. The Remarkable Adsorption Capacity of Zinc/Nickel/Copper-Based Metal–Organic Frameworks for Thiophenic Sulfurs. RSC. Adv. 2016, 6, 105827–105832.


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(14) Wang, T. T.; Li, X. X.; Dai, W.; Fang, Y. Y.; Huang, H. Enhanced Adsorption of Dibenzothiophene with Zinc/Copper-Based Metal-Organic Porous Material. J. Mater Chem. A 2015, 3, 21044–21050. (15) Zheng, S. T.; Zhang, J.; Yang, G. Y. Designed Synthesis of POM–Organic Frameworks from Ni6PW9 Building Blocks under Hydrothermal Conditions. Angew. Chem. Int. Edit. 2008, 47, 3909–3913. (16) Sun, C. Y.; Liu, S. X.; Liang, D. D.; Shao, K. Z.; Ren, Y. H.; Su, Z. M. Highly Stable Crystalline Catalysts Based on a Microporous Metal-Organic Framework and Polyoxo Metalates. J. Am. Chem. Soc. 2009, 131, 1883–1888. (17) Ahmed, I.; Jhung, S. H. Adsorptive Desulfurization and Denitrogenation Using Metal-Organic Frameworks. J. Hazard. Mater. 2016, 301, 259–276. (18) Khan, N. A.; Jhung, S. H. Adsorptive Removal and Separation of Chemicals with Metal-Organic Frameworks: Contribution of π-Complexation. J. Hazard. Mater. 2017, 325, 198–213. (19) Khan, N. A.; Jhung, S. H. Adsorptive Removal of Benzothiophene Using Porous Copper-Benzenetricarboxylate Loaded with Phosphotungstic Acid. Fuel Process. Technol. 2012, 100, 49–54. (20) Canioni, R.; Roch-Marchal, C.; Sécheresse, F.; Horcajada, P.; Serre, C.; Hardi-Dan, M.; Férey, G.; Grenéche, J. M.; Lefebvre, F.; Chang, J. S.; Hwang, Y. K.; Lebedev, O.; Turner, S.; Tendeloo, G. V. Stable Polyoxometalate Insertion within the Mesoporous Metal Organic Framework MIL-100(Fe). J. Mater. Chem.

2011, 21, 1226–1233.


Page 18 of 30

Page 19 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

(21) Dai, W.; Hu, J.; Zhou, L. M.; Li, S.; Hu, X.; Huang, H. Removal of Dibenzothiophene with Composite Adsorbent MOF-5/Cu(I). Energy Fuels 2013, 27, 816–821. (22) Dai, W.; Zhou, Y. P.; Li, S. G.; Li, W.; Su, W.; Sun, Y.; Zhou, L. Thiophene Capture with Complex Adsorbent SBA-15/Cu(I). Ind. Eng. Chem. Res. 2006, 45, 7892–7896. (23) Tan, P.; Xie, X. Y.; Liu, X. Q.; Pan, T.; Gu, C.; Chen, P. F.; Zhou, J. Y.; Pan, Y. C.; Sun, L. B. Fabrication of Magnetically Responsive HKUST-1/Fe3O4 Composites

by

Dry

Gel

Conversion

for

Deep

Desulfurization

and

Denitrogenation. J. Hazard. Mater. 2017, 321, 344–352. (24) Shi, R.; Zhang, Z. R.; Fan, H. L.; Zhen, T.; Shangguan, J.; Mi, J. Cu-Based Metal–Organic Framework/Activated Carbon Composites for Sulfur Compounds Removal. App. Sur. Sci. 2017, 394, 394–402 (25) Khan, N. A.; Yoon, J. W.; Chang, J. S.; Jhung, S. H. Enhanced Adsorptive Desulfurization with Flexible Metal–Organic Frameworks in the Presence of Diethyl Ether and Water. Chem. Commun. 2016, 52, 8667–8670. (26) Jung, B. K.; Jhung, S. H. Adsorptive Removal of Benzothiophene from Model Fuel, Using Modified Activated Carbons, in Presence of Diethylether. Fuel 2015, 145, 249–255. (27) Cychosz, K. A.; Wong-Foy, A. G.; Matzger, A. J. Liquid Phase Adsorption by Microporous Coordination Polymers: Removal of Organosulfur Compounds. J. Am. Chem. Soc. 2008, 130, 6938–6939.


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 20 of 30

(28) Jia, S. Y.; Zhang, Y. F.; Liu, Y.; Qin, F. X.; Ren, H. T.; Wu, S. H. Adsorptive Removal of Dibenzothiophene from Model Fuels over One-Pot Synthesized PTA@MIL-101(Cr) Hybrid Material. J. Hazard. Mater. 2013, 262, 589–597. (29) Wu, L.; Xiao, J.; Wu, Y.; Xian, S.; Miao, G.; Wang, H.; Li, Z. A Combined Experimental/Computational

Study

on

the

Adsorption

of

Organosulfur

Compounds over Metal-Organic Frameworks from Fuels. Langmuir 2014, 30, 1080–1088.


Page 21 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

Figure captions: Figure 1. N2 adsorption/desorption isotherms and pore size distributions for (Zn, Ni, Cu)-BTC

and

PTA@(Zn,

Ni,

Cu)-BTC

samples

at

-196

o

C.

(A):

N2

adsorption/desorption isotherms; (B): Pore distribution.

Figure 2. XRD analysis for (Zn, Ni, Cu)-BTC sample before and after loading PTA Figure 3. SEM images of (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples. (A): (Zn, Ni, Cu)-BTC; (B): PTA(0.5)@(Zn, Ni, Cu)-BTC

Figure 4. IR spectra of (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC. Figure 5. TGA of (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC under nitrogen atmosphere.

Figure 6. NH3-TPD profiles of (Zn, Ni, Cu)-BTC and PTA@(Zn, Ni, Cu)-BTC adsorbents.

Figure 7. Breakthrough curves of DBT in the ALF over (Zn, Ni, Cu)-BTC before and after loading PTA at room temperature (25 oC).

Figure 8. Breakthrough curves of DBT in the ARF over (Zn, Ni, Cu)-BTC before and after loading PTA at room temperature (25 oC).

Figure 9. Breakthrough curves of DBT in the MIF over (Zn, Ni, Cu)-BTC before and after loading PTA at room temperature (25 oC).

Figure 10. Breakthrough curves of DBT in the acetone-ALF over the (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples at room temperature (25 oC).

Figure 11. Breakthrough curves of DBT in the acetone-ARF over the (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples at room temperature (25 oC).


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 12. Breakthrough curves of DBT in the acetone-MIF over the (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples at room temperature (25 oC).

Figure 13. Breakthrough curves of DBT in the ALF, ARF and MIF over the PTA(0.5)@(Zn, Ni, Cu)-BTC after five regeneration times.


Page 22 of 30

Page 23 of 30

400

(Zn, Ni, Cu)-BTC

(A)

300

3

Volume adsorbed (cm /g, STP)

350

PTA(0.2)@(Zn, Ni, Cu)-BTC

250 200

PTA(0.5)@(Zn, Ni, Cu)-BTC 150

PTA(1.0)@(Zn, Ni, Cu)-BTC 100 50 0 0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Relative pressure(P/P0)

0.8

(B)

(Zn, Ni, Cu)-BTC PTA(0.2)@(Zn, Ni, Cu)-BTC PTA(0.5)@(Zn, Ni, Cu)-BTC PTA(1.0)@(Zn, Ni, Cu)-BTC

0.7

3

Incremental pore volume (cm /g)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

0.6 0.5 0.4 0.3 0.2 0.1 0.0 0

1

2

3

4

5

Pore diameter (nm)

Figure 1. N2 adsorption/desorption isotherms and pore distribution for (Zn, Ni, Cu)-BTC

and

PTA@(Zn,

Ni,

Cu)-BTC

samples

adsorption/desorption isotherms; (B): Pore distribution.


at

-196

o

C.

(A):

N2

Energy & Fuels

28000

o

11.58

o

o

o

9.44 13.36

25.94

o

19

24000

Intensity (au.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 24 of 30

PTA(0.2)@(Zn, Ni, Cu)-BTC o 35.12


20000

16000


12000

(Zn, Ni, Cu)-BTC 8000

PTA 4000 0

10

20

30

40

50

Two-theta (deg.)

Figure 2. XRD analysis for (Zn, Ni, Cu)-BTC sample before and after loading PTA (A)

(B)

Figure 3. SEM images of (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples. (A): (Zn, Ni, Cu)-BTC; (B): PTA(0.5)@(Zn, Ni, Cu)-BTC


Page 25 of 30

400 350 (Zn, Ni, Cu)-BTC

Transmission (%)

300 250

PTA(0.5)@(Zn, Ni, Cu)-BTC 200 150

PTA

100 50 1565 1374 1645 1444 1081

0 3400

730

985 827

-50 -100 4000

3500

3000

2500

2000

1500

1000

500

-1

Wavenumbers (cm )

Figure 4. IR spectra of PTA, (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC.

100 90

Weight percent (wt %)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

80 70


60 50 40 30

(Zn, Ni, Cu)-BTC

20 10 0 0

50

100 150 200 250 300 350 400 450 500 550 600 650 o

Temperature ( C)

Figure 5. TGA of (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC under nitrogen atmosphere.


Energy & Fuels

Intensity (a.u.)


PTA(0.5)@(Zn, Ni, Cu)-BTC PTA(0.2)@(Zn, Ni, Cu)-BTC (Zn, Ni, Cu)-BTC

250

300

350

400

450

o

Temperature ( C)

Figure 6. NH3-TPD profiles of (Zn, Ni, Cu)-BTC and PTA@(Zn, Ni, Cu)-BTC adsorbents.

1.0


0.8

0.6

Ct /Co

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 26 of 30

0.4

0.2

0.0 0

50

100

150

200

250

300

3

Veff (cm /g)

Figure 7. Breakthrough curves of DBT in the ALF over (Zn, Ni, Cu)-BTC before and after loading PTA at room temperature (25 oC).


Page 27 of 30

1.0


Ct /Co

0.8

0.6

0.4

0.2

0.0 0

50

100

150

200

250

300

3

Veff (cm /g)

Figure 8. Breakthrough curves of DBT in the ARF over (Zn, Ni, Cu)-BTC before and after loading PTA at room temperature (25 oC).

1.0


0.8

Ct /Co

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

0.6

0.4

0.2

0.0 0

50

100

150

200

250

300

3

Veff (cm /g)

Figure 9. Breakthrough curves of DBT in the MIF over (Zn, Ni, Cu)-BTC before and after loading PTA at room temperature (25 oC).


Energy & Fuels

1.0

0.8

ALF+Acetone (Zn, Ni, Cu)-BTC

Ct /Co

0.6

ALF (Zn, Ni, Cu)-BTC 0.4

ALF+Acetone PTA(0.5)@(Zn, Ni, Cu)-BTC

0.2

ALF PTA(0.5)@(Zn, Ni, Cu)-BTC

0.0 0

50

100

150

200

250

300

3

Veff (cm /g)

Figure 10. Breakthrough curves of DBT in the acetone-ALF over the (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples at room temperature (25 oC).

1.0

ARF+Acetone (Zn, Ni, Cu)-BTC 0.8

Ct /Co

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 28 of 30

ALF (Zn, Ni, Cu)-BTC

0.6

0.4

ARF+Acetone PTA(0.5)@(Zn, Ni, Cu)-BTC

0.2

ARF PTA(0.5)@(Zn, Ni, Cu)-BTC 0.0 0

50

100

150

200

250

300

3

Veff (cm /g)

Figure 11. Breakthrough curves of DBT in the acetone-ARF over the (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples at room temperature (25 oC).


Page 29 of 30

1.0

Ct /Co

0.8

MIF+Acetone (Zn, Ni, Cu)-BTC

0.6

MIF (Zn, Ni, Cu)-BTC 0.4

MIF+Acetone PTA(0.5)@(Zn, Ni, Cu)-BTC

0.2

MIF PTA(0.5)@(Zn, Ni, Cu)-BTC

0.0 0

50

100

150

200

250

300

3

Veff (cm /g)

Figure 12. Breakthrough curves of DBT in the acetone-MIF over the (Zn, Ni, Cu)-BTC and PTA(0.5)@(Zn, Ni, Cu)-BTC samples at room temperature (25 oC). 1.0

0.8

Ct /Co

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Energy & Fuels

ARF

0.6

ALF

MIF

0.4

0.2

0.0 0

50

100

150

200

250

300

3

Veff (cm /g)

Figure 13. Breakthrough curves of DBT in the ALF, ARF and MIF over the PTA(0.5)@(Zn, Ni, Cu)-BTC after eight regeneration times.


Energy & Fuels 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 30 of 30

(Zn, Ni, Cu)-BTC Functionalized with Phosphotungstic Acid for Adsorptive Desulfurization in the Presence of Benzene and Ketone Wei Dai,*,† Ning Tian,† Congmin Liu,‡ Le Yu,† Qing Liu,† Na Ma,§ and Yuexing Zhao† †

Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Zhejiang Normal

University, Jinhua 321004, People’s Republic of China ‡

National Institute of Clean-and-Low-Carbon Energy, Beijing 102211, People’s Republic of China

§College

of Geography and Environmental Sciences, Zhejiang Normal University, Jinhua 321004,

People’s Republic of China

PTA (Zn, Ni, Cu)-BTC

PTA@(Zn, Ni, Cu)-BTC

A new type of metal–organic framework, PTA@(Zn, Ni, Cu)-BTC, has been successfully developed, which shows a promising potential for practical deep desulfurization.


(Zn, Ni, Cu)-BTC Functionalized with Phosphotungstic Acid for

Recommend Documents