DOI: 10.1002/ ((please add manuscript number)) Full Paper

Novel Organics-Dehydration Membranes Prepared from Zirconium Metal-Organic Frameworks

Xinlei Liu, Chenghong Wang, Bo Wang, and Kang Li*

Dr. X. Liu, C. Wang, Dr. B. Wang, Prof. Dr. K. LiDepartment of Chemical EngineeringImperial College LondonLondon, SW7 2AZ, United KingdomE-mail: kang.li@imperial.ac.ukC. WangGraduate School for Integrative Sciences & EngineeringDepartment of Civil and Environmental EngineeringNational University of Singapore117576, Singapore

Keywords: metal-organic framework, membrane, UiO-66, hollow fiber, pervaporation

Abstract: Membranes with outstanding performance that are applicable in harsh

environments are needed to broaden the current range of organics dehydration applications

using pervaporation. Here, well-intergrown UiO-66 metal-organic framework membranes

fabricated on pre-structured yttria-stabilized zirconia hollow fibers is reported via controlled

solvothermal synthesis. On the basis of adsorption-diffusion mechanism, the membranes

provides a very high flux of up to ca. 6.0 kg m-2 h-1 and excellent separation factor (> 45000)

for separating water from i-butanol (next-generation biofuel), furfural (promising

biochemical) and tetrahydrofuran (typical organic). This performance, in terms of separation

factor, is one to two orders of magnitude higher than that of commercially available polymeric

and silica membranes with equivalent flux. It is comparable to the performance of commercial

zeolite NaA membranes. Additionally, the membrane remains robust during a pervaporation

stability test (~300 hours), including exposure to harsh environments (e.g., boiling benzene,

boiling water and sulfuric acid) where some commercial membranes (e.g., zeolite NaA

membranes) cannot survive.

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1. Introduction

Pervaporation, a membrane separation process based on adsorption-diffusion mechanism, [1]

has been considered as a promising energy efficient technology for molecular-scale liquid /

liquid separations. [2] Quite a few pervaporation membranes have been made commercially

available for organics dehydration. [2a] However, new membrane materials that are able to

provide enhanced performance and hold robustness in harsher conditions are still on demand

to extend the current range of pervaporation applications. [2a]

Metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) have emerged as

a family of porous crystalline materials composed of metal containing units stitched together

by organic ligands. [3] Their wide topological varieties and customizable chemistry render

MOFs to be superior membrane materials for diverse potential applications. [4] Recently, a

number of promising results have been reported in fabricating polycrystalline MOF

membranes for gas separation. [5, 6] Nevertheless, the investigation of these membranes for

pervaporation is still in its infancy, particularly in systems involving water. [4, 7] Expediting the

development of MOF membranes in pervaporation is extremely challenging as it may require

novel qualified MOF materials, and defect-free membranes need to be fabricated on porous

substrates.

As a subfamily of MOFs, a series of chemical and thermal stable zirconium (IV) MOFs (Zr-

MOFs) have been unveiled since 2008. [8] UiO-66 (UiO stands for University of Oslo) is a

prototypical Zr-MOF, with a formula of Zr6O4(OH)4(BDC)6 (BDC = 1,4-benzene-

dicarboxylate) and fcu topology (Figure 1a).[8a] Its aperture size is around 0.6 nm as estimated

from crystallographic data.[8a] This material possesses hydrophilic adsorption sites since plenty

hydroxyl groups are involved in its framework. [8b] Very recently, we developed UiO-66

membranes for water desalination. [9] The membranes exhibited high rejection for multivalent

ions. However, its water flux is moderate. In this study, UiO-66 polycrystalline membranes

with outstanding pervaporation performance were developed on pre-structured substrates

2

using controlled solvothermal synthesis. The membranes can effectively dehydrate biofuels

(e.g., butanol), biochemicals (e.g., furfural) and other organics (e.g., tetrahydrofuran, THF)

with excellent stability (Figure 1a).

2. Results and Discussion

2.1. YSZ Hollow Fiber Substrates

Porous ceramic yttria-stabilized zirconia (YSZ) hollow fibers (HF) were specially designed

and used as substrates in virtue of their merits, which include high packing density, low

transport resistance, easy scale-up, good mechanical strength and outstanding chemical and

thermal stability. [10] Since UiO-66 is constructed by zirconium clusters and BDC ligands, [8a]

another reason to employ this type of substrate is that they could possibly provide zirconium

to chemically bond with BDC ligands (discussed below), and thus promoting the

heterogeneous nucleation of UiO-66. The HF geometry was carefully created via a combined

phase inversion / sintering approach. As shown in Figure 1 b-e, the as-synthesized HF is

approximately 1.1 mm in OD (outer diameter). The wall with a thickness of around 200 µm

contains three sponge-like layers sandwiching two layers of micro-channels. The sponge

layers contribute to mechanical strength enhancement and also provide relatively smooth

surfaces (outer layer, pore size is around 80 nm) for depositing additional thin membrane

layers, while the micro-channel layers would reduce resistance for molecule permeation.

2.2. Formation and Characterization of UiO-66 Membranes

UiO-66 polycrystalline membranes were fabricated on the pre-structured YSZ HF by in-situ

solvothermal approach via a careful control of the heating duration, composition and

temperature of the synthetic mother solutions. A standard preparation recipe is given in the

Experimental Section. To understand the membrane formation mechanism, SEM (Scanning

3

Electron Microscope), XRD (X-ray Diffraction) and FTIR-ATR (Fourier Transform Infrared-

Attenuated Total Reflection) characterizations were conducted as shown in Figure 2. A

schematic diagram is given in Figure S1. First, after 2 hours of heating, a very thin amorphous

gel layer was formed on the surface of the substrate as confirmed by the SEM images (Figure

2a and 2b) and XRD patterns (Figure 2l and Figure S2). This is possibly caused by the

aggregation of gel particles formed in the mother solution, which were transported to the

substrate due to Brownian motion and chemical interaction between the ligands and substrate

(discussed below). During the consequent synthesis, heterogeneous nucleation occurred

probably at the interface of the gel and the solution (Figure 2c and 2d), the only place where

both the ligand and metal source were present in abundance. The diffraction peaks of UiO-66

crystals started to rise in the XRD pattern (Figure 2l and Figure S3). Meanwhile, further gel

settlement could still be proceeding, which buried and disturbed some of the UiO-66 nuclei

(Figures 2c and 2d). After this nucleation period, crystals propagated through the gel network

and then sank to the substrate (Figures 2e and 2f) by consuming the gel around them. The

particle size of UiO-66 crystal is around 100 nm at this stage. This propagation process was

followed by or parallel with the aggregation and densification of nanocrystals. With

prolonged heating, crystal growth took place (Figures 2g-2l) by acquisition of nutrients from

bulk solution, from nearby unreacted amorphous gel and small UiO-66 crystals (Ostwald

ripening). A well-intergrown membrane layer (Figures 2i-2k) was finally formed after 48

hours’ continuous heating after narrowing intercrytalline gaps (Figure 2g).

Since this membrane was prepared with simultaneous growth and nucleation, UiO-66 crystals

emerged on the surface of membrane layer was identified in the SEM image (Figure 2k). As

demonstrated by the XRD pattern (Figure 2l), a pure phase polycrystalline UiO-66 membrane

with random orientation was fabricated. The UiO-66 grains are approximately 0.3-0.8 μm in

size with sharp edges (Figure 2i). The membrane thickness is ca. 1.0 μm (Figures 2j and 2k),

which is only half of what was previously reported for a UiO-66 membrane, [9] because the 4

designed YSZ hollow fibers not only can provide relatively smooth surface but also promote

the heterogeneous nucleation.

To verify whether chemical interactions between the ligands and substrate exist or not, FTIR-

ATR characterization was carried out. Bare YSZ powders were prepared by grinding the

sintered YSZ HF, and then dispersed in the same solution that was used for membrane

fabrication without adding the zirconium source. After heating for 48 hours at 120 oC, the

powders were isolated and thoroughly rinsed and dried. As indicated in Figure 2m, the bare

YSZ powders did not exhibit relevant absorption in the frequency range between 1350 and

1710 cm-1, whereas in the case of BDC ligands, strong peaks presented in virtue of the

stretching vibration of carboxyl groups (1423 and 1674 cm-1) and phenyl rings (1574 cm-1).

After the above treatment with BDC ligands, clear peaks appeared in the IR spectra of YSZ

powders (Figure 2m, middle). Considerable blue / red shifts were observed corresponding to

the stretching vibration of carboxyl groups (1440 and 1658 cm-1) and phenyl rings (1593 cm-

1). [11] This data signifies that chemical bonds were established between the ligands and

substrate, probably between the carboxyl and zirconium. This chemical interaction provides

an evidence to disclose the EDXS (Energy-Dispersive X-ray Spectroscopy) mapping (Figure

2k). Although no visible UiO-66 crystals were recognized in the bulk substrate (Figure 2j),

slight intrusion of C signal (orange) into the substrate (Y signal, green) was detected. This

might be due to the fact that the substrate was chemically modified by the BDC ligands

during membrane preparation. The chemical interaction can enhance the adhesion of the

membrane layer to the substrate to a large extent, and consequently the membrane stability is

improved.

2.3. Separation Performance and Stability of UiO-66 Membranes

The synthesized membrane contained guest molecules within its cavities before activation. An

on-stream pervaporation test (see Experimental Section and Figure S4) was conducted to 5

empty the cavities and to monitor the activation process simultaneously. An n-butanol

aqueous solution was applied (5.00 wt. % water, 30 oC) as feed. At the early stage of

activation, considerable n-butanol molecules could pass through the membrane together with

water (Figure 3). This is understandable since the kinetic diameters of water (ca. 0.3 nm) and

n-butanol (ca. 0.5 nm) molecules are smaller than the aperture of UiO-66 (around 0.6 nm).

Following the activation, water concentration increased gradually in permeate because of the

increase of water flux, although the total flux did not change obviously (Figure 3). After

around 24 hours’ continuous pervaporation test, water concentration in the permeate reached a

plateau value of approximately 99.60 wt. % with a total flux around 1.20 kg m-2 h-1. It is

suspected that the hydrophilic adsorption sites, i.e. hydroxyl groups, in the cavities were

partly hindered by some guest molecules before activation. These guest molecules could be

removed by the passing through water and n-butanol molecules during activation process.

Therefore, more hydrophilic adsorption sites were open and available to preferentially adsorb

water against n-butanol molecules. This is why an enhancement of water flux and water / n-

butanol selectivity was accomplished after activation.

After activation, a stability test of the membrane was carried out towards water / n-butanol

and water / furfural solutions (5.00 wt. % water in each solution, 30oC). Butanol is a

representative next-generation biofuel [12a] and furfural (furan-2-carbaldehyde) is a promising

platform biochemical. [12b, c] Both of them can be commercially produced in water medium

from biomass. [12] As shown in Figure 3, benefiting from the excellent chemical stability of

UiO-66 materials [8a, 9, 13] and good attachment of membrane layer to substrate, the membrane

remained robust even after a treatment with boiling benzene and water. No discernible

degradation of membrane performance was observed during the following test of more than

200 hours. In both cases of water / n-butanol and water / furfural separations, the water

concentration in permeate was equal or higher than 99.60 wt. %. When the feed was switched

from n-butanol to furfural aqueous solution, the total flux was increased to around 1.80 kg m-2

6

h-1. This is attributed to the enhanced chemical potential of water in the feed side (see

Experimental Section). In order to further check the membrane stability, H2SO4 was

introduced to the feed (pH ~ 2), which is a benchmark acid catalyst for producing biofurfural.

[12b, c] The membrane kept robust even in this acid solution (Figure 3). As reported,

applications of commercially available pervaporation membranes towards harsh conditions

are restricted. [2a] Polymeric membranes (e.g., Poly(vinyl alcohol)) have poor solvent stability

[2a] and inorganic membranes (e.g., zeolite NaA) are unstable in present of acid or high water

content feed. [14] The above mentioned stability test data reveal that the newly developed UiO-

66 membrane is capable of being used in harsh conditions, which may broaden the industrial

applications of pervaporation.

Apart from purifying n-butanol and furfural, the membrane performance was evaluated for

separating water from other typical biofuels (e.g. i-butanol and ethanol) and organics (e.g.

propanol, THF and acetone) at elevated temperatures. As illustrated in Table 1, Table S1 and

S2, the selectivity of water over organic molecules increased with the increase of organic

kinetic diameters in virtue of the lower permeance of bigger molecules (Figure 4a),

demonstrating a size selective diffusion in the pervaporation process. The selectivity and

water permeance changed with feed concentration and temperature (Table 1 and Table S1);

this indicates that water adsorption has influence on the membrane performance to some

extent, which verified the hypothesis proposed in the above activation process.

The membranes developed in this work exhibit a very high performance for separating water

from i-butanol, furfural and THF, in terms of an ultrahigh separation factor (> 45000) and

appealing flux of up to ca. 6.0 kg m-2 h-1 based on duplicate experiments (Table 1). These

results prove that the as-synthesized polycrystalline membranes were well-intergrown and the

membrane fabrication method is reproducible. The membrane performance, in terms of

separation factor, is one to two orders of magnitude higher than that of commercially

available polymeric and silica membranes with equivalent flux (Table S3). [15a, b] It is 7

comparable to the performance of commercial zeolite NaA membranes. [15c] The excellent

stability together with outstanding membrane performance recommends UiO-66 to be a novel

hydrophilic pervaporation membrane, which may potentially widen the current application

range of commercial membranes. The high water concentration in permeate remained even

when the concentration and temperature of feed solutions were modulated (Figure 4b and 4c).

Due to the enhanced chemical potential of water molecules, the total flux goes up with the

increase of temperature and water concentration in feed solutions, although molecule

diffusivity heavily rely on temperature.

3. Conclusion

In summary, new type of membranes for organics dehydration were developed based on

zirconium metal-organic frameworks. The as-synthesized UiO-66 membranes supported on

pre-structured YSZ hollow fibers provided excellent performance for purifying typical

biofuels, biochemicals and organics under harsh environments, which over-performed the

commercially available membranes for pervaporation. The property of Zr-MOFs, including

high stability and tunable structures and functional groups, suggests that this type of materials

have a great potential to be developed as the next-generation pervaporation membranes.

4. Experimental Section

Preparation of YSZ hollow fibers: The YSZ hollow fibers were fabricated by a phase

inversion combined sintering method. [10] 120 g of YSZ powders (30-60nm, 3mol % yttria,

Inframat Advanced Materials, LLC), 20 g of Polyethersulfone (Radal A300, Ameco

Performance, USA) and 1.0 g of dispersant (Arlacel P135, polyethylene glycol 30-

dipolyhydroxystearate, Uniqema) were dispersed by ball milling in 80 g of

dimethylsulphoxide (HPLC grade, VWR), to form a ceramic suspension with a high

homogeneity and stability. After degassing, the resultant suspension was transferred to a

metallic syringe and extruded through a tube-in-orifice spinneret (2.0 mm outer diameter, 1.0

8

mm inner diameter) to obtain the hollow fiber precursors in water bath with a dope (bore)

flow rate of 5.0 ml / min (10 ml / min) and air gap of 2.0 cm. Then, the hollow fiber

precursors were sintered at 1150 oC to gain mechanical strength.

Preparation of UiO-66 membranes: Controlled in situ solvothermal growth approach was

employed to fabricate UiO-66 membranes on the pre-structured YSZ hollow fibers (80 mm in

length). The synthetic mother solution was prepared by dissolving 0.419 g of ZrCl4 (>99.5%,

Sigma Aldrich), 0.299 g of BDC ligands (98%, Sigma Aldrich), and 0.0320 g of DI water

(Analytic lab, ACEX, Imperial College London) in 67.5 g of N,N-Dimethylformamide (DMF,

99.8%, VWR) with the assistance of ultrasonic. Then, this clear solution was transferred into

a Teflon-lined stainless steel autoclave where a hollow fiber was placed vertically with both

ends sealed to allow membrane growing on the outer surface. Afterwards, the autoclave was

placed in a convective oven and heated at 120 oC for 48 hours. After cooling, the membrane

was flushed with DMF and dried under ambient condition.

Characterizations: The SEM images coupled with EDXS were performed on a LEO Gemini

1525 instrument at an accelerating voltage of 5kV and 20 kV, respectively. Panalytical Xpert

XRD (using Cu Kα radiation, λ=0.154 nm at 40kV and 40mA) was employed to analyze the

crystalline structure of powders, membranes and substrates. FTIR-ATR spectra were recorded

on a spectrometer (Spectrum 100, PerkinElmer). The feed and permeate concentrations in the

pervaporation test were measured by an off-line GC (GC 3900, Varian. Inc.).

Pervaporation: The performance of the membranes was assessed via pervaporation test for

separating water from organics (Figure S4). Each time, 10 min was given to the system for

stabilization before collecting samples. The pressure of the permeate side was kept at around

250 Pa. During the stability test, feed concentration was kept constant by compensating the

loss of water to permeate. The total permeation flux (Equation 1) was measured by weighing

the condensed permeate:

J = W / (A×t), (1)9

where W refers to the weight of permeate (kg), A the membrane area (m2), t the duration (h)

of the sample collection. The separation factor (Equation 2) is defined as:

ɑ = (Ywater / 1–Ywater) / (X water / 1–X water), (2)

where Xwater and Ywater denote the mass fraction of water in the feed and permeate sides,

respectively. Membrane permeance (Equation 3) is flux normalized by the chemical potential:

Pi = Ji / pi, (3)

where Ji refers to the flux of permeate i, pi the chemical potential of component i. The

chemical potential was simulated using the computer program CHEMCAD. The selectivity

(Equation 4) is defined as:

S = Pwater / Porganic, (4)

where Pwater and Porganic refer to the permeance of water and organic, respectively.

Supporting Information Supporting Information is available from the Wiley Online Library or from the author.

AcknowledgementsSupported by Engineering and Physical Sciences Research Council of UK (EP/J014974/1) and (EP/M01486X/1). The authors acknowledge Dr. Melanie Lee for her contribution in fine-tuning the manuscript.

Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))

Published online: ((will be filled in by the editorial staff))

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Figure 1. a) Schematic illustration of separating water from organics (e.g., biobutanol, biofurfural and tetrahydrofuran) by using a UiO-66 membrane. In the unit cell of UiO-66 (right), cyan, white and red spheres represent Zr, C and O atoms, respectively. H atoms are not shown for clarity. Photo (b) and SEM images of YSZ hollow fibers: c), d): cross section; e): outer surface.

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Figure 2. SEM surface and cross section images of UiO-66 membranes after synthesis for different times: a, b, 2 hours; c, d, 4 hours; e, f, 12 hours; g, h, 24 hours; i, j, 48 hours. Visible intercrystalline pinholes are marked with ellipses in Figure 1g. k) EDXS mapping image of the cross section of UiO-66 membrane after synthesis for 48 hours: C signal, orange; Y signal, green. l) XRD patterns of the UiO-66 membranes after synthesis for different times: 2, 4, 12, 24, and 48 hours, from bottom to top. The diffraction peaks assigned to UiO-66 phase have been labelled with stars. For XRD characterization, UiO-66 membranes were fabricated on YSZ discs instead of hollow fibers using the same membrane fabrication method. m) FTIR-ATR spectra of the BDC ligands (bottom), sintered YSZ powders after BDC treatment (middle), and sintered YSZ powders (top). For clarity, arrows are marked to the absorption peaks of the BDC modified YSZ.

14

Figure 3. Flow chart and pervaporation performance of UiO-66 membrane for separating water from n-butanol and furfural during on-stream activation and stability test processes at 30 oC. The concentration of water in each feed was kept at 5.00 wt. %.

15

Figure 4. a) Water and organic permeance vs. their kinetic diameters. The concentration of water in each feed was set at 5.00 wt. %. This figure was made based on Tables S1 and S2. Cylindrical molecules are not shown because the Stockmayer length parameter does not represent the minimum cross-sectional diameter. [14] b) Effect of water concentration in the feed on the pervaporation performance at 30 oC. c) Effect of feed temperature on the pervaporation performance using 5.00 wt. % aqueous solutions as feed. For figure b) and c), filled and open triangles represent membrane performance for separating water from n-butanol and furfural, respectively.

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Table 1. Pervaporation performance of UiO-66 membranes for separating water from typical biofuels, biochemicals and organics based on duplicate experiments. The temperature of feed composition was set at 70 oC except for tetrahydrofuran (THF) and acetone aqueous solutions, where the temperature was 50 oC. It is out of the detection of GC when the concentration of organics is lower than 0.02wt. %.

Feed(10.00wt. % water)

Total flux(kg m-2 h-1)

Water permeance

(10-6 mol m-2 s-

1 pa-1)

Water con. in permeate (wt.

%)Selectivity

Separation factor

Water / ethanol 3.73±0.12 3.62±0.13 86.12±0.20 68.0±1.2 55.8±1.0

Water / n-propanol 4.65±0.10 3.73±0.09 97.40±0.23 168±17 337±30

Water / i-propanol 4.62±0.09 3.75±0.07 98.71±0.11 641±55 689±55

Water / n-butanol 5.38±0.12 3.50±0.08 99.79±0.02 835±81 4280±410

Water / i-butanol 4.81±0.11 3.13±0.07 >99.98 >13400 >45000

Water / furfural 5.95±0.08 3.08±0.04 >99.98 >2360 >45000

Water / THF 4.06±0.11 7.29±0.20 a) >99.98 >99000 >45000

Water / acetone 3.99±0.12 7.26±0.22 a) 99.45±0.03 4760±260 1630±90

a) The water permeance increased when THF and acetone solutions were employed as feed because the adsorption of water was enhanced when the temperature decreased.

17

Table of contents Novel membranes for pervaporation: Well-intergrown metal-organic framework UiO-66 membranes are developed on pre-structured YSZ hollow fibers. The membranes provide excellent performance for purifying typical biofuels, biochemicals and organics under harsh environments.

Keywordsmetal-organic framework, membrane, UiO-66, hollow fiber, pervaporation

AuthorsXinlei Liu, Chenghong Wang, Bo Wang, and Kang Li*

TitleNovel Organics-Dehydration Membranes Prepared from Zirconium Metal-Organic Frameworks

ToC figure

18

Copyright WILEY-VCH Verlag GmbH & Co. KGaA, 69469 Weinheim, Germany, 2013.

Supporting Information

Novel Organics-Dehydration Membranes Prepared from Zirconium Metal-Organic Frameworks

Xinlei Liu, Chenghong Wang, Bo Wang, and Kang Li*

19

Figure S1. Schematic illustration of the proposed formation mechanism of UiO-66 membrane synthesized by in-situ solvothermal method.

Figure S2. XRD pattern of YSZ disc. YSZ discs were prepared by phase inversion combined sintering method using the same YSZ powders and calcination temperature as YSZ hollow fibers.

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Figure S3. XRD pattern of UiO-66 powders collected from the mother solution after membrane synthesis for 48 hours. This XRD pattern and the diffraction peaks of the crystalline membrane (Figure 2l in the main text) coincide with that of the standard UiO-66 samples. [1, 2]

Figure S4. Diagram of pervaporation setup used in this work.

At 20 °C, the bare hollow fiber substrate showed N2 permeance of 1.7 × 10−5 mol m−2 s−1 Pa−1 under the pressure difference of 1.0 bar across the membrane. Its water permeance is 190 L m-

2 h-1 bar-1 under a transmembrane pressure of 10.0 bar. The details of gas and water permeation systems were reported elsewhere. [1]

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Table S1. Pervaporation performance of UiO-66 membranes for separating water from biofuels, biochemicals and organics. The temperature of feed composition was set at 70 oC except for tetrahydrofuran (THF) and acetone aqueous solutions, where the temperature was 50 oC. The concentration of water in each feed was set at 5.00 wt. %.

FeedTotal flux(kg m-2 h-1)

Water permeance(10-6 mol m-2 s-1 pa-1)

Water con. in permeate (wt.%)

SelectivitySeparation

factor

Water / ethanol 2.55 2.94 62.52 32.9 31.7

Water / n-propanol 2.46 2.92 93.13 105 258

Water / i-propanol 2.45 2.96 95.10 281 369

Water / n-butanol 2.71 2.60 99.58 694 4500

Water / i-butanol 2.70 2.59 99.89 4070 17300

Water / furfural 3.75 2.66 99.96 1840 47500

Water / THF 2.05 5.84 99.85 24200 12600

Water / acetone 2.43 5.69 99.27 3860 2020

Table S2. Kinetic diameters of water and organic molecules. [3] Cylindrical molecules are not

shown because the Stockmayer length parameter does not represent the minimum cross-

sectional diameter. [4]

Molecules Kinetic diameter (nm)

Water 0.296

Ethanol 0.430

i-Propanol 0.470

i-Butanol 0.504

THF 0.486

Acetone 0.469

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Table S3. Organics dehydration performance of commercial pervaporation membranes.

Commercial Membranes Company Feed Separation

factorTotal flux

(kg m-2 h-1) Ref.

Silica Pervatech BV Water / ethanol, 5 wt. %, 75 oC 100 3.0 5

Silica PERVAP SMS Sulzer Chemtech Water / t-butanol, 10wt.%, 60 oC 144 3.5 6

Silica PERVAP SMS Sulzer Chemtech Water / i-propanol, 8.2 wt. %, 70 oC 53 1.9 7

Silica ECN Water / n-butanol 1.0-5.0 wt. %, 70 oC 680-1340 0.4-2.3 8

Silica ECN Water / i-butanol 9.6 wt. %, 75 oC 1200 3.88 9

Silica ECN Water / THF 11.8 wt. %, 60 oC 210 3.47 9

NaA Nanotec Research institute Water / ethanol, 10 wt. %, 75 oC 20000-40000 3.5-4.0 5,10

NaA Nanotec Research institute Water / i-propanol, 10 wt. %, 75 oC 10000 3.5-3.7 10

NaA Nanotec Research institute Water / ethanol, 10 wt. %, 75 oC 10000 8.0 11

NaA Mitsui Water / n-butanol, 10 wt. %, 75 oC 90000 1.39 9

NaA Mitsui Water/ THF, 10.4 wt.%, 60 oC 12000 1.78 9

NaA SMART Chemical Company Water / THF, 7 wt. %, 55 oC 1240 0.98 12

NaA SMART Chemical Company Water / t-butanol, 10 wt.%, 60 oC 16000 1.5 6

NaA NanjingJiusi Hi-Tech Co. Ltd

Water / ethylene glycol, 20 wt.%, 120 oC 5000 4.0 13

PVA PERVAP 2510 Sulzer Chemtech Water / t-butanol, 10 wt. %, 60 oC 3615 0.5 6

PVA GFT Water / i-propanol 10 wt. %, 60 oC 450 0.10 14

Acrylic copolymer CMCelfa Water/ THF 7 wt. %, 65 oC 628 1.54 15

Polyelectrolytes GKSS Water/ acetone 10 wt. %, 40 oC 150 0.47 16

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