The First Example of Commensurate Adsorption of Atomic Gas in a MOF and Effective Separation of Xenon from Other Noble Gases

Transcription

1 The Frst Example of Commensurate Adsorpton of Atomc Gas n a MOF and Effectve Separaton of Xenon from Other Noble Gases Hao Wang, a Ke Xn Yao, b Zhjuan Zhang, c Jacek Jagello, d Qhan Gong, a Yu Han b and Jng L* a a Department of Chemstry and Chemcal Bology, Rutgers Unversty, 61 Taylor Road, Pscataway, New Jersey, 8854, USA b Advanced Membranes and Porous Materals Center, Physcal Scences and Engneerng Dvson, and Imagng and Characterzaton Core Lab, Kng Abdullah Unversty of Scence and Technology, Thuwal , Saud Araba c Insttute of Atmospherc Envronment Safety and Polluton Control, Jnan Unversty, Guangzhou, 51632, Chna d Mcromertcs Instrument Corporaton, 4356 Communcatons Drve, Norcross, GA, 393 *Correspondence should be drected to: jngl@rutgers.edu Supportng Informaton 1

2 I. Synthess and structure characterzaton Reagents and materals: All chemcals were purchased from Sgma Aldrch, Alfa Aesar and used as receved wthout further purfcaton unless stated otherwse. Synthess of Co3(HCOO)6: A mxture of Cobalt (II) ntrate hexahydrate (1.39g, 4.4 mmol) and formc acd (1mL, 25.7mmol) n DMF (1 ml) n a glass val was heated at 1 C for 24 hours and then cooled to room temperature. The resultant pnk powder of was fltered, rnsed wth DMF (1 ml) and dred under ar. Same procedure was employed n the syntheses of other M3(HCOO)6 (M=N, Mn) compounds. Instrument and method: Powder X-ray dffracton patterns were recorded on a Rgaku D/M-22T automated dffractometer (Ultma+) usng Cu Kα radaton (λ = Å). Graphte monochromator was used and the generator power settngs were at 44 kv and 4 ma. Data were collected between a 2 of 3-5 wth a step sze of.2 at a scannng speed of 3. deg/mn. (a) 2

3 (b) (c) Fqure S1. PXRD patterns of (a) Co3(HCOO)6, (b) N3(HCOO)6, (c) Mn3(HCOO)6. From bottom to top: smulated (black), as made (red), after gas sorpton experments (blue). II. Thermal stablty Instrument and method: Thermogravmetrc data were collected on a TA Q5 Analyzer wth a temperature rampng rate of 1 C/mn from room temperature to 6 C under ntrogen gas flow. 3

4 (a) (b) 4

5 (c) Fgure S2. Thermogravmetrc analyss of freshly prepared samples. (a) Co3(HCOO)6, (b) N3(HCOO)6, (c) Mn3(HCOO)6. Showng a good agreement between the observed weght loss of solvent DMF and the calculated value (14.3%, 14.1%, and 14.57% for Co, N, and Mn respectvely). III. Gas sorpton experments Instrument and method: Gas sorpton experments at ambent temperatures were performed usng a volumetrc gas sorpton analyzer (Autosorb-1 MP, Quantachrome Instruments). Measurements at cryogenc temperatures were carred out usng a hghresoluton Mcromertcs 3Flex adsorpton nstrument. The 3Flex (Mcromertcs) was equpped wth hgh-vacuum system, three.1 Torr pressure transducers, and was coupled wth a cryostat (Cold Edge Technologes) that mantans the cryogenc temperatures wth a stablty n the range of +/_.1 K from the target temperature. Ultra hgh purty Xenon, Krypton, Ar and Ne (99.999%) were used. The ntal outgassng process for each sample was carred out at 393K overnght (under vacuum). Outgassed samples n the amount of ~1mg were used for gas sorpton measurements and the weght of each sample was recorded before and after outgassng to confrm the 5

6 removal of guest molecules. The outgassng procedure was repeated on the same sample between experments for 2~4 hour. Xenon and Krypton sorpton sotherms n M3(HCOO)6 (M = N and Mn) at dfferent temperature are shown n Fgure S3. Fgure S3. Adsorpton and desorpton sotherms of Xenon n N3(HCOO)6 (Top Left); Krypton n N3(HCOO)6 (Top Rght); Xenon n Mn3(HCOO)6 (Bottom Left); Krypton n Mn3(HCOO)6 (Bottom Rght). Table S1. Summary of xenon adsorpton on M3(HCOO)6 (M = Co, N, Mn) seres Formula Co3(HCOO)6 N3(HCOO)6 Mn3(HCOO)6 Space group P21/n N/A P21/n V unt cell (Å3) N/A Densty of as made (g/cm3) N/A 1.86 Densty of solvent free (g/cm3) 1.82 N/A Uptake (cc/g) at 298K, 1bar Uptake (w%) at 298K, 1bar Uptake (mmol/g) at 298K, 1bar Uptake (mmol/cm3) at 298K, 1bar 3.59 N/A 2.67 Uptake (mole/uc) at 298K, 1bar 3.52 N/A 2.91 Uptake (mole/seg) at 298K, 1bar.88 N/A.73 Uptake (mole/seg) 288K, 1bar.89 N/A.77 6

7 Uptake (mole/seg) 278K, 1bar.89 N/A.78 Table S2. Summary of xenon/krypton selectvty n M3(HCOO)6 (M = Co, N, Mn) seres at 298 K Formula Co3(HCOO)6 N3(HCOO)6 Mn3(HCOO)6 Xe Uptake at 1bar, mmol/g Kr Uptake at 1bar, mmol/g Henry s constant of Xe adsorpton, mmol/g/bar Henry s constant of Kr adsorpton, mmol/g/bar Rato of uptake Xe/Kr selectvty by the rato of Henry s constant IV. Henry s constant fttng Low pressure range of the adsorpton sotherm s nearly lnear whch corresponds to Henry s law behavor. Thus Henry s constant can be obtaned from a lnear ft to the ntal part of the sotherm. In our case, the fttng s appled to the range where P <.1 bar to guarantee t s wthn Henry s regon. Fttng of Xe adsorpton sotherm n Co3(HCOO)6.6.5 Uptake, mmol/g y = 1.28x R 2 = Pressure, bar 7

8 Fttng of Kr adsorpton sotherm n Co3(HCOO)6.5 Uptake, mmol/g y =.8718x R 2 = Pressure, bar Fttng of Ar adsorpton sotherm n Co3(HCOO)6.2 Uptake, mmol/g y =.1379x R 2 = Pressure, bar Fttng of Xe adsorpton sotherm n N3(HCOO)6 Uptake, mmol/g y = x R 2 = Pressure, bar 8

9 Fttng of Kr adsorpton sotherm n N3(HCOO)6 Uptake, mmol/g y = 1.125x R 2 = Pressure, bar Fttng of Xe adsorpton sotherm n Mn3(HCOO)6.4 Uptake, mmol/g y = x R 2 = Pressure, bar 9

10 Fttng of Kr adsorpton sotherm n Mn3(HCOO)6.5 Uptake, mmol/g y =.7268x R 2 = Pressure, bar Fttng of Kr adsorpton sotherm n Mn3(HCOO)6.2 Uptake, mmol/g y =.2497x R 2 = Pressure, bar Fgure S4. Fttng of Henry s constant. V. Ideal adsorbed soluton theory (IAST) selectvty The deal adsorbed soluton theory (IAST) developed by Myers and Prauntz 1 assumes that the adsorbed mxture s an deal soluton at constant spreadng pressure and temperature, where all the components n the mxture conform to the rule analogous to Raoult s law, and the chemcal potental of the adsorbed soluton s consdered equal to that of the gas phase at equlbrum. From the IAST, the spreadng pressure s gven by 1

11 RT p ( p ) qd ln p A (1) * A p q dp RT p (2) Where A s the specfc surface area of the adsorbent, π and π * are the spreadng pressure and the reduced spreadng pressure, separately. p s the gas pressure of component that correspondng to the spreadng pressure π of the gas mxture. At a constant temperature, the spreadng pressure of sngle component s the same: * * * 1... n (3) 2 The relaton between the mole fracton n the gaseous phase y, and the mole fracton n the adsorbed phase x s descrbed by Raoult s law for deal solutons, P y p ) x (4) ( * Where p s the pressure of the sngle component n ts standard state whch s fxed by the spreadng pressure of the mxture accordng to Eq (3). Fnally, the total number of moles adsorbed can be obtaned from: n 1 x (5) q q ( p ) t Where q ( ) s the adsorbed amount from the pure component sotherms. p The selectvty of j over s S j p p j Py / x Py j / x j x y j j y x (6) Dual Ste Langmur-Freundlch Model for Xe, Kr, and Ar Adsorpton Isotherms The Dual ste Langmur-Freundlch (DSLF) model 2 can be expressed as follows: N b p 1/ n1 1. n2 max 1 max 2 N1 N 1/ 2 (7) n1 1/ n2 1 b1 p 1 b2 p b p Here, p s the pressure of the bulk gas at equlbrum wth the adsorbed phase (kpa), N s the adsorbed amount per mass of adsorbent (mol/kg), N 1 max and N 2 max are the 11

12 saturaton capactes of stes 1 and 2 (mol/kg), b1 and b2 are the affnty coeffcents of stes 1 and 2 (1/kPa), and n 1 and n2 represent the devatons from an deal homogeneous surface. The sngle-component Xe and Kr adsorpton sotherms have been ft to enable the applcaton of IAST n smulatng the performance of 1' under a mxed component gas. The fttng parameters of DSLF equaton as well as the correlaton coeffcents (R2) are lsted n Table S3. The expermental and ftted sotherm for Xe and Kr at 298 K are depcted n Fgure S5. Table S3. Equaton parameters for the DSLF sotherm model Adsorbates N1 max b1 N2 max n1 (mmol/g) (kpa -1 ) (mmol/g) b2 (kpa -1 ) n2 R 2 Xe Kr Ar

13 Fgure S5. Expermental and ftted sotherms for Xe, Kr and Ar at 298K VI. Isosterc heats of adsorpton (Qst) of noble gases n Co3(HCOO)6 measured at cryogenc temperatures In order to further understand the nteractons between atoms of noble gases and the framework, we measured adsorpton sotherms of Xe, Kr, and Ar at three temperatures (18, 19, 2 K) and Ne also at three temperatures but n a lower range (8, 9, 1 K) to calculate the sosterc heats of adsorpton Qst of these noble gases. The sosterc heats of adsorpton (Qst) can be obtaned by usng the vral equaton. 3 ln( p) ln( v) (1/ T) a v b v m n j (8) j j where v, p, and T are amount adsorbed, pressure, and temperature, respectvely. Fttng equaton (6) to adsorpton data measured at dfferent temperatures gves a set of temperature ndependent parameters a and b whch are used n drect evaluaton of Qst m st (9) Q R a v Where R s the unversal gas constant. Expermental adsorpton sotherms of Xe, Kr, and Ar measured on Co3(HCOO)6 sample and the goodness of ft by curves ftted by equaton (6) are shown n Fgures S6 S8. 13

14 1 Uptake (mmol/g) 1.1 Xe-18 K Xe-19 K Xe-2 K Ft.1 1e-6 1e-5 1e-4 1e-3 1e-2 1e-1 1e+ Pressure (bar) Fgure S6. Xenon adsorpton sotherms measured at 18, 19 and 2 K on Co3(HCOO)6 and ther ft by equaton Uptake (mmol/g).1.1 Kr-18 K Kr-19 K Kr-2 K Ft.1 1e-5 1e-4 1e-3 1e-2 1e-1 1e+ Pressure (bar) Fgure S7. Krypton adsorpton sotherms on Co3(HCOO)6 and ther ft by equaton 8. 14

15 1 1 Ar-18 K Ar-19 K Ar-2 K Ft Uptake (mmol/g) Pressure (bar) Fgure S8. Argon adsorpton sotherms on Co3(HCOO)6 and ther ft by equaton 8. Table S4. Emprcal parameters from fttng of vral equaton Xe Kr Ar a -3.26E E+3-2.E+3 a1-1.36e e E-1 a2-5.39e E E+ a3 1.46E E E+1 a4-1.13e E+1 a5 2.87E+2 VII. Breakthrough experments In a typcal breakthrough experment, ~5 mg of MOF sorbent was gently ground and packed nto a quartz column (5.8 mm I.D. 15 mm) wth slca wool fllng the vod space. The sorbent was n stu actvated n the column wth a helum flow (1 ml mn 1 ) at 15 C for 2 h before the temperature of the column was decreased to 25 C. The flow of He was then turned off whle a gas mxture of Kr/Xe (9:1, v/v) at 1. ml 15

16 mn 1 was sent nto the column. The effluent from the column was montored usng a mass spectrometer (MS). The dead tme was determned usng the same column after adsorpton saturaton. Breakthrough tmes were calculated by subtractng the dead tme from the observed breakthrough tme (Fgure S9). Fgure S9. Column breakthrough experment for Xe/Kr:1/9 bnary gas system at 298 K and 1 bar n Co3(HCOO)6, (Black): Kr and (Red): Xe. References: 1. A. L. Myers and J. M. Prausntz, AIChE Journal, 1965, 11, (a) G. Arora and S. I. Sandler, J. Chem. Phys., 25, 123; (b) R. Babarao, Z. Hu, J. Jang, S. Chempath and S. I. Sandler, Langmur, 26, 23, ; (c) Y.-S. Bae, O. K. Farha, A. M. Spokoyny, C. A. Mrkn, J. T. Hupp and R. Q. Snurr, Chemcal Communcatons, 28,, ; (d) Y.-S. Bae, K. L. Mulfort, H. Frost, P. Ryan, S. Punnathanam, L. J. Broadbelt, J. T. Hupp and R. Q. Snurr, Langmur, 28, 24, ; (e) Z. Zhang, Z. L and J. L, Langmur, 212, 28, (a) L. Czeprsk and J. JageŁŁo, Chemcal Engneerng Scence, 1989, 44, ; (b) J. Jagełło, T. J. Bandosz and J. A. Schwarz, Langmur, 1996, 12, ; (c) B. Chen, X. Zhao, A. Putkham, K. Hong, E. B. Lobkovsky, E. J. Hurtado, A. J. Fletcher and K. M. Thomas, Journal of the Amercan Chemcal Socety, 28, 13,