Method for Producing Silicoaluminophosphate Sorbent

Abstract

The invention relates to a method for synthesizing silicoaluminophosphate sorbents such as SAPO-56 and SAPO-47 comprising the use of a specific structure directing agent (SDA) comprising a mixture of different types of amines The structure providing agent (SDA) comprises N,N,N,N-tetramethyl-1,6-hexanediamine (TMHD) and a co-structure providing agent (co-SDA) selected among primary, secondary and tertiary amines comprising up to 15 carbon atoms and mixtures thereof. A preferred SDA comprises isopropylamine, dibutylamine and tripropylamine The sorbents are particularly suitable for up-grading biogas such as separating carbon dioxide from methane.

Claims

1. A method for preparing a silicoaluminophosphate sorbent comprising: providing a reaction mixture, said mixture comprising: a silicon-containing composition, an aluminum-containing composition, a phosphorous-containing composition, and a structure directing agent (SDA); crystallization of the reaction mixture thereby providing crystallized silicoalum inophosphate; recovering crystalline silicoaluminophosphate from the mixture; wherein the structure providing agent (SDA) comprises N,N,N,N-tetramethyl-1,6-hexanediamine (TMHD) and a co-structure providing agent (co-SDA) selected among primary, secondary and tertiary amines comprising up to 15 carbon atoms and mixtures thereof.

2. The method according to claim 1, wherein the co-SDA is selected among primary amines comprising a saturated hydrocarbon comprising up to 6 carbon atoms.

3. The method according to claim 1, wherein the silicoaluminophosphate sorbent is selected among SAPO-47 and SAPO-56.

4. The method according to claim 1, wherein the silicoaluminophosphate sorbent is SAPO-56.

5. The method according to claim 1, wherein the SDA comprises up to about 75% wt of the co-SDA.

6. The method according to claim 1, wherein the primary, secondary and tertiary amines comprise saturated hydrocarbons.

7. The method according to claim 6, wherein the saturated hydrocarbons comprise from 2 up to 4 carbon atoms.

8. The method according to claim 1, wherein the co-SDA is selected among isopropylamine (IPA), dibutylamine (DBA), tripropylamine (TPA) and mixtures thereof.

9. A method for preparing a SAPO-56 sorbent comprising: providing a reaction mixture, said mixture comprising a silicon-containing composition; an aluminum-containing composition; a phosphorous-containing composition; and a structure directing agent (SDA), crystallization of the reaction mixture thereby providing crystallized silicoalum inophosphate; recovering crystalline silicoaluminophosphate from the mixture, wherein the structure providing agent (SDA) comprises at least a primary amine comprising a saturated hydrocarbon comprising up to 6 carbon atoms.

10. The method according to claim 9, wherein the primary amine comprises up to 3 carbon atoms.

11. The method according to claim 9, wherein the primary amine is isopropylamine (IPA).

12. The method according to claim 9, wherein the SDA further comprises N,N,N,N-tetramethyl-1,6-hexanediamine (TMHD).

13. A silicoaluminophosphate sorbent obtained by the method according to claim 1.

14. A silicoaluminophosphate sorbent comprising a structure providing agent (SDA) comprising N,N,N,N-tetramethyl-1,6-hexanediamine (TMHD) and a co-structure providing agent (co-SDA) selected among primary, secondary and tertiary amines comprising up to 15 carbon atoms and mixtures thereof.

15. The silicoaluminophosphate sorbent according to claim 14, wherein the silicoaluminophosphate sorbent comprises SAPO-56 and optionally SAPO-47 and the co-SDA is isopropylamine (IPA).

16. The silicoaluminophosphate sorbent according to claim 14, wherein the silicoaluminophosphate sorbent comprises SAPO-56 and co-structure providing agents (co-SDAs), where the amount of co-SDAs is at least about 10 mol % and the BET specific surface area (m.sup.2/g) is above about 500.

17. The silicoaluminophosphate sorbent according to claim 14, wherein the silicoaluminophosphate sorbent comprises SAPO-56 comprising particles, said particles having a mean particle size of less than about 1000 nm.

18. The silicoaluminophosphate sorbent according to claim 14, wherein the silicoaluminophosphate sorbent comprises SAPO-56 comprising particles being bipyramidal and/or hexagonal plates.

19. A process for the separation of CO2 from methane, the process comprising the use of a sorbent as defined by claim 13.

Description

FIGURES

[0056] FIG. 1: XRD patterns of the as synthesized products obtained with different ratios of TMHD to IPA and the reference pattern of SAPO-56 (indicated as SAPO-56 00-052-1178). Entries from top to bottom: SAPO-56-00-052-1178, S4 100% TMHD, S12 60% TMHD:40% IPA, S15 50% TMHD:50% IPA, S20 40% TMHD:60% IPA, S38 70% TMHD:30% IPA, S56 80% TMHD:20% IPA, S58 10% TMHD:90% IPA.

[0057] FIG. 2: X-ray diffraction patterns of the as synthesized products obtained with co-SDA 70% IPA: 30% TMHD as function of the crystallization time at 210 C. (Entries top to bottom: SAPO-56 00-052-1178, 39A (48 h), 39B (77 h), 39C (98 h), S31A (114 h).

[0058] FIG. 3: X-ray diffraction patterns of the as synthesized products obtained with co-SDA 70% IPA:30% TMHD and 48 h crystallization time as function of the temperature. Entries top to bottom: SAPO-56 00-052-1178, S45 180 C., S47 190 C., S50 200 C., S49 210 C.

[0059] FIG. 4: XRD patterns of the as synthesized and calcined SAPO-56 obtained with co-SDA SDA 70% IPA:30% TMHD and 48 h (Sample S50 of Table 4) showing the structure stability after co-SDAs removal. The reference pattern of SAPO-56 00-052-1178 is add for comparison. Entries top to bottom: SAPO-56 00-052-1178, S50, S50 650 C.

[0060] FIG. 5: CO.sub.2 (top line) and CH.sub.4 (bottom line) adsorption isotherms measured at 10 C. for SAPO-56 30% TMHD: 70% IPA (sample S50 of Table 4).

[0061] FIG. 6: XRD patterns of the as synthesized products obtained with co-SDA 60% TMHD: 40% IPA in contrast with the reference pattern of SAPO-56 00-052-1178. Entries top to bottom: SAPO-56 00-052-1178, S10, S11, S12, S16.

[0062] FIG. 7: SEM images of SAPO-56 using 60% TMHD: 40% IPA (sample S12 of Table 4) shows at least two different morphologies: short hexagonal pillar and based faced pyramids.

[0063] FIG. 8: XRD patterns of the as synthesized products obtained with co-SDA 50% TMHD: 50% IPA in contrast with the reference pattern of SAPO-56 00-052-1178. Entries top to bottom: SAPO-56 00-052-1178, S5, S13, S14, S15, S17, S22.

[0064] FIG. 9: SEM images of SAPO-56 as-synthesized using 50% TMHD: 50% IPA (sample S17 of Table 4) show base faced pyramids of approximately 2 m size.

[0065] FIG. 10: XRD patterns of the as synthesized products obtained with co-SDA 40% TMHD: 60% IPA in contrast with the reference pattern of SAPO-56 00-052-1178. Entries top to bottom: SAPO-56 00-052-1178, S18, S19, S20, S21, S27.

[0066] FIG. 11: SEM images of SAPO-56 using 40% TMHD: 60% IPA (sample S12 of Table 4)

[0067] FIG. 12: XRD patterns of the as synthesized products obtained with co-SDA 30% TMHD: 70% IPA in contrast with the reference pattern of SAPO-56 00-052-1178 using different autoclave filling. Entries top to bottom: SAPO-56 00-052-1178, S4, S48 20% v/v, S49 30% v/v, S50 40% v/v.

[0068] FIG. 13: SEM images of SAPO-56 using 30% TMHD: 70% IPA (sample S50 of Table 4)

[0069] FIG. 14: SEM images of (a, b) SAPO-47 and (c) SAPO-56/SAPO-47 intergrowth obtained using 30% TMHD: 70% IPA and 48 h at different crystallization temperatures. Reaction conditions of sample S45, S47 and S50 of Table 4.

[0070] FIG. 15: XRD patterns of the as synthesized products obtained with co-SDA 20% TMHD: 80% IPA. The characteristic peaks at low angle 2 values of 9.48 and 12.9 correspond to SAPO-47 (Treacy and Higgins 2007) which is synthesized using n-propylamine as template (Xu et al. 2015, 123-128). Entries top to bottom: SAPO-56 00-052-1178, S55, S56.

[0071] FIG. 16: SEM images of SAPO-47 synthesized using 20% TMHD: 80% IPA (sample S55 of Table 4) showing hexagonal plates of rough surface.

[0072] FIG. 17: XRD patterns of the as synthesized products obtained with co-SDA 10% TMHD: 90% IPA. The characteristic peaks at low angle 2 values of 9.48 and 12.9 correspond to SAPO-47 (Treacy and Higgins 2007) which is synthesized using n-propylamine as template (Xu et al. 2015, 123-128). Entries top to bottom: SAPO-56 00-052-1178, S57, S58.

[0073] FIG. 18: SEM images of SAPO-47 synthesized using 10% TMHD: 90% IPA (sample S58 of Table 4) showing semi-circular grains composed by nanosized cubes.

[0074] FIG. 19: N.sub.2 adsorption isotherms measured at 196 C. for sample S50 70% IPA: 30% TMHD (BET SSA 670 m.sup.2/g).

[0075] FIG. 20: CO.sub.2 (top line) and CH.sub.4 (bottom line) adsorption isotherms measured at 0 C. for SAPO-56 obtained using TMHD and 95 h (sample S5 Table 1).

[0076] FIG. 21: CO.sub.2 (top line) and CH.sub.4 (bottom line) adsorption isotherms measured at 0 C. for SAPO-47 using 80% IPA: 20% TMHD and 51 h (sample S56 of Table 4).

[0077] FIG. 22: CO.sub.2 (top black solid lines) and CH.sub.4 (bottom red dotted lines) adsorption isotherms measured at 0 C. for SAPO-56 synthesized using (A) only TMHD and (B) TMHD:co-SDAs. See Table 5 for detailed information.

[0078] FIG. 23: (A) Synthesis composition diagram of the gel used for the synthesis of SAPO-56 using TMHD. (B) XRD pattern of SAPO-56 as-synthesized samples. Literature data on the synthesis of pure SAPO-56 (small blue circles) are presented in 1A. The SiO.sub.2 in the ternary diagram is defined as SiO.sub.2/(SiO.sub.2+Al.sub.2O.sub.3+P.sub.2O.sub.5).sub.gel. (Consult the color version of this Figure).

[0079] FIG. 24: (A) Synthesis composition diagram of gels, (B) XRD pattern, (C-D) SEM images of samples synthesized using IPA as co-SDA. Gel compositions used for the synthesis of pure SAPO-56 and SAPO-47 reported in the literature are highlighted in (A) in addition to the points of this study. Table 5 for detailed gel composition and reaction conditions. The SiO.sub.2 in the ternary diagram is defined as SiO.sub.2/(SiO.sub.2+Al.sub.2O.sub.3+P.sub.2O.sub.5).sub.gel. TMHD and IPA stands for N,N,N,N-tetramethyl-1,6-hexanediamine and isopropylamine, respectively. Consult the color version of this figure.

[0080] FIG. 25: (A) Synthesis composition diagram of gels, (B) XRD pattern, (C-D) SEM images of samples synthesized using DBA as co-SDA. Gel compositions used for the synthesis of pure SAPO-56 and SAPO-17 reported in the literature are highlighted in (A) in addition to the points of this study. Table 5 for detailed gel composition and reaction conditions. The SiO.sub.2 in the ternary diagram is defined as SiO.sub.2/(SiO.sub.2+Al.sub.2O.sub.3+P.sub.2O.sub.5).sub.gel. TMHD and DBA mean N,N,N,N-tetramethyl-1,6-hexanediamine and DBA. Consult the color version of this figure.

[0081] FIG. 26: A) Synthesis composition diagram of gels, (B) XRD pattern, (C-D) SEM images of samples synthesized using TPA as co-SDA. Gel compositions used for the synthesis of pure SAPO-56, SAPO-17 and SAPO-11 reported in the literature are highlighted in (A) in addition to the points of this study. Table 5 presents the detailed gel compositions and reaction conditions. The SiO.sub.2 in the ternary diagram is defined as SiO.sub.2/(SiO.sub.2+Al.sub.2O.sub.3+P.sub.2O.sub.5).sub.gel. TMHD and TPA mean N,N,N,N-tetramethyl-1,6-hexanediamine and tripropylamine. Consult the color version of this figure.

EXPERIMENTAL DATA

[0082] SAPO-56 seeds were synthesized by a hydrothermal method using 100% of the classical and expensive structure directing agent, template 1, N,N,N,N tetramethyl-1,6-hexanediamine (99% Sigma Aldrich) following the protocol reported (Xie et al. 2013, 6732-6735). Precursors were added in the following order: H.sub.2O, phosphoric acid, aluminum source, silica source, and the SDA. A starting solution of phosphoric acid (85 wt %, Sigma Aldrich) in distilled water (DI H.sub.2O) and the aluminum source, pseudoboehmite, (Aluminum Corporation of China, Shandong) was prepared under vigorously stirring for two hours at room temperature. The silica source was added to the former solution in the form of LUDOX HS-40 colloidal silica, 40 wt. % suspension in water (Sigma Aldrich) and stirred continuously for 1 h. Finally, the SDA was added. A temporary increase in the temperature and concurrent thickening of the mixture was visible during the first minutes of the mixing. The mixture was continued to be stirred for at least 18 h at room temperature in closed vessel. The prepared suspension/gel having a pH of 10 was transferred to Teflon-lined stainless-steel autoclaves and introduced in a pre-heated oven at a temperature of 210 C. The crystallization of SAPO-56 was performed hydrothermally under an autogenous pressure for 96 h. The formed product had two layers. The minor top layer of a yellow and gelatinous appearance was discarded. The white cake at bottom of the autoclaves was recovered, washed with an excess of deionized (DI) H.sub.2O (using at least three centrifugations, with 6000 rpm for 5 min, and washing cycles) and dried at a temperature of 80 C. overnight. Finally, as-synthesized SAPO-56 was calcined at a temperature of 650 C. for 16 h before further testing was performed.

[0083] SAPO-56 was prepared using N,N,N,N tetramethyl-1,6-hexanediamine (TMHD: 99% Sigma Aldrich) and IPA (>99.5%, Sigma Aldrich) as a co-structure directing agent.

[0084] The precursors were added in the following order: water, phosphoric acid, aluminum source, silica source, TMHD, IPA, and seeds. The ratio of IPA: TMHD was varied using IPA from 10 to 90% in molar percentage.

[0085] A starting solution of phosphoric acid (85 wt %, Sigma Aldrich) in distilled water (DI H.sub.2O) and the aluminum source, pseudoboehmite, (Aluminum Corporation of China, Shandong) was prepared under vigorously stirring for two hours at room temperature. The silica source was added to the former solution in the form of LUDOX HS-40 colloidal silica, 40 wt. % suspension in water (Sigma Aldrich) and stirred continuously for 1 h. Finally, the TMHD and IPA was added in a sequence where TMHD was added first and then after 5 minutes followed by the addition of IPA.

[0086] A temporary increase in the temperature and a thickening of the mixture was visible during the first minutes after TMHD addition; however, the viscosity of the mixtures returned, roughly, back to its initial value after the addition of the IPA. The suspension/gel was continuously stirred for at least 18 h at room temperature in closed vessel. The solution with a pH=7 was transfer to Teflon lined stainless-steel autoclaves and placed in a pre-heated oven at a temperature of 195-210 C. under autogenous pressure. A crystallization time of 48 h was applied. The gelatinous top layer of the formed product was discarded, and the white cakes at the bottom of the autoclaves were recovered. The recovered white cakes were subsequently washed with an excess of DI H.sub.2O (and at least three centrifugations, at 6000 rpm for 5 min, and washing cycles were applied) and dried at a temperature of 80 C. overnight. Finally, the as-synthesized product was calcined at a temperature of 650 C. for 12 h before further experimentation.

[0087] Table 2 summarizes the different mixture compositions tested for the synthesis SAPO-56 using only TMHD and different rations of TMHD and IPA. For more detail, Table 2 shows some compositions using co-SDAs.

TABLE-US-00002 TABLE 2 Working Temperature Time volume Crystalline Sample TMHD:IPA Al.sub.2O.sub.3 P.sub.2O.sub.5 SiO.sub.2 TMHD IPA H.sub.2O Seed ( C.) (h) (v/v %) phase S5 100%:0% 0.9 1.0 1.9 2.2 0 54.9 NO 210 95 16% SAPO-56 S12 60%:40% 0.8 1.0 0.9 1.3 0.9 52.3 YES 210 95 14% SAPO-56 S15 50%:50% 0.8 1.0 0.9 1.0 1.1 52.3 NO 210 95 14% SAPO-56 S20 40%:60% 0.8 1.0 0.9 0.8 1.3 52.2 YES 210 96 14% SAPO-56 S38 30%:70% 0.7 1.0 0.7 0.5 1.2 42.7 YES 210 48 14% SAPO-56 S55 20%:80% 0.7 1.0 0.8 0.4 1.4 44.0 YES 195 51 40% SAPO-47 S58 10%:90% 0.7 1.0 0.8 0.2 1.6 44.3 YES 195 51 40% SAPO-47

TABLE-US-00003 TABLE 3 Particle size determined from SEM Mean particle Sample TMHD:IPA size (nm) SD Min Max n Morphology Crystalline phase S5 100%:0% 96+E3 17+E3 78.5+E3 124+E3 9 Round plate SAPO-56 S12 60%:40% 157.1 19.5 117.3 188.4 12 Bipyramids SAPO-56 and hexagonal plates S15 50%:50% 215.5 23.4 187.9 253.8 8 Bipyramids SAPO-56 S20 40%:60% 214.8 23.3 176 289 18 Hexagonal SAPO-56 plates S38 30%:70% 331.7 48.4 264.1 445.8 37 Hexagonal SAPO-56 plates S55 20%:80% 337.3 38.4 265.9 395.9 22 Hexagonal SAPO-47 plates S58 10%:90% 381.4 44 303.3 473.5 29 Hexagonal SAPO-47 plates S81 0:100% 427.3 136.3 276.5 703 16 Rhomboidal SAPO-47 shape

TABLE-US-00004 TABLE 4 Gel composition for SAPO-56 synthesis using IPA as co-SDA Working Temperature Time volume Crystalline Sample TMHD:IPA Al.sub.2O.sub.3 P.sub.2O.sub.5 SiO.sub.2 TMHD IPA H.sub.2O Seed ( C.) (h) (v/v %) phase S10 60%:40% 0.8 1.0 0.9 1.3 0.8 52.3 NO 210 95 50% SAPO-56, unidentified phase S11 60%:40% 0.8 1.0 0.9 1.3 0.8 52.4 NO 210 95 14% SAPO-56, unidentified phase S12 60%:40% 0.8 1.0 0.9 1.3 0.9 52.3 YES 210 95 14% SAPO-56 S13 50%:50% 0.8 1.0 0.9 1.0 1.1 52.3 NO 210 95 14% SAPO-56 S14 50%:50% 0.8 1.0 0.9 1.1 1.1 52.6 YES 210 95 14% SAPO-56 S15 50%:50% 0.8 1.0 0.9 1.0 1.1 52.3 NO 210 95 14% SAPO-56 S16 60%:40% 0.8 1.0 0.9 1.3 0.8 52.3 YES 210 95 50% SAPO-56 S17 50%:50% 0.8 1.0 0.9 1.0 1.1 52.3 YES 210 95 50% SAPO-56, unidentified phase S18 40%:60% 0.8 1.0 0.9 0.8 1.3 52.4 YES 210 96 50% SAPO-56, unidentified phase S19 40%:60% 0.8 1.0 0.9 0.8 1.3 52.2 YES 210 72 14% SAPO-56, unidentified phase S20 40%:60% 0.8 1.0 0.9 0.8 1.3 52.2 YES 210 96 14% SAPO-56 S21 40%:60% 0.8 1.0 0.9 0.8 1.2 51.9 NO 210 96 14% SAPO-56, unidentified phase S22 50%:50% 0.8 1.0 0.9 1.1 1.1 52.4 YES 210 72 50% SAPO-56, unidentified phase S23 50%:50% 0.8 1.0 0.9 1.0 1.1 52.0 YES 210 96 14% NO PRODUCT S24 30%:70% 0.8 1.0 0.9 0.6 1.5 52.2 YES 210 96 49% SAPO-56, unidentified phase S25 30%:70% 0.8 1.0 0.9 0.6 1.5 52.2 YES 210 96 14% SAPO-56, unidentified phase S27 40%:60% 0.8 1.0 0.9 0.8 1.3 52.2 YES 210 96 14% SAPO-56 S28 40%:60% 0.8 1.0 0.9 0.8 1.3 52.4 YES 210 114 14% NO PRODUCT S29 30%:70% 0.7 1.0 0.8 0.5 1.3 44.3 YES 210 114 14% SAPO-56 S30 30%:70% 0.8 1.0 0.9 0.6 1.5 51.7 YES 210 114 14% NO PRODUCT S31A 30%:70% 0.8 1.0 0.9 0.6 1.5 51.5 YES 210 114 12% SAPO-56, unidentified phase S31B 30%:70% 210 114 12% SAPO-56, unidentified phase S31C 30%:70% 210 114 12% SAPO-56, unidentified phase S32 30%:70% 0.8 1.0 0.9 0.8 1.3 52.4 YES 210 114 47% SAPO-56, unidentified phase S37A 30%:70% 0.9 1.0 1.9 0.7 1.6 54.9 YES 210 98 12% SAPO-56, unidentified phase S37B 30%:70% 98 12% SAPO-56, unidentified phase S37C 30%:70% 98 12% SAPO-56, unidentified phase S38 30%:70% 0.7 1.0 0.7 0.5 1.2 42.7 YES 210 48 14% SAPO-56 S39A 30%:70% 0.7 1.0 0.8 0.5 1.3 44.2 YES 210 48 12% SAPO-56 S39B 30%:70% 210 77 12% SAPO-56, unidentified phase S39C 30%:70% 210 99 12% SAPO-56, unidentified phase S40 30%:70% 0.7 1.0 0.8 0.5 1.2 44.3 YES 100 48 30% NO PRODUCT S41 30%:70% 0.8 1.0 0.9 0.6 1.4 51.5 YES 210 77 14% SAPO-56, unidentified phase S42 30%:70% 0.8 1.0 0.9 0.6 1.5 51.9 YES 210 99 14% SAPO-56, unidentified phase S43 30%:70% 0.8 1.0 0.9 0.6 1.5 51.9 YES 210 148 14% SAPO-56, unidentified phase S45 30%:70% 0.7 1.0 0.8 0.5 1.2 43.7 YES 180 47 40% SAPO-47 S47 30%:70% 0.7 1.0 0.8 0.6 1.3 43.9 YES 190 47 40% SAPO-47 S48 30%:70% 0.7 1.0 0.8 0.5 1.3 44.2 YES 200 48 20% SAPO-56, unidentified phase S49 30%:70% 0.7 1.0 0.8 0.5 1.3 44.2 YES 200 48 30% SAPO-56, unidentified phase S50 30%:70% 0.7 1.0 0.8 0.5 1.2 43.7 YES 200 48 40% SAPO-56, unidentified phase S51 30%:70% 0.7 1.0 0.7 0.5 1.2 43.2 YES 200 48 12% SAPO-56, unidentified phase S52 30%:70% YES 200 48 30% SAPO-56 S53 30%:70% 0.7 1.0 0.8 0.6 1.2 44.0 YES 195 51 40% SAPO-56, unidentified phase S54 30%:70% 0.7 1.0 0.8 0.5 1.2 44.3 YES 195 51 40% SAPO-56, unidentified phase S55 20%:80% 0.7 1.0 0.8 0.4 1.4 44.0 YES 195 51 40% SAPO-47 S56 20%:80% 0.7 1.0 0.8 0.4 1.4 44.0 YES 195 51 40% SAPO-47 S57 10%:90% 0.7 1.0 0.8 0.2 1.6 44.3 YES 195 51 40% SAPO-47 S58 10%:90% 0.7 1.0 0.8 0.2 1.6 44.3 YES 195 51 40% SAPO-47

[0088] The success of using the IPA as a co-SDA was observed in the XRD pattern of the samples in the series. FIG. 1 shows the corresponding XRD patterns of the as synthesized products synthesized with co-SDA TMHD: IPA. The diffraction pattern of samples using 40 to 70% of IPA show peaks attributed to low-angle crystalline planes (100), (101), (102) and (110) of SAPO-56. Higher amount of IPA (i.e. 80 to 90%) lead to formation of other phase of SAPO. The lines 13.85 and 24.15 correspond to lines for the XRD of SAPO-17 (ERI) identified in some of the synthesis of SAPO-56 with only the TMHD template were not observed. The characteristic peaks at low angle 2 values of 9.48 and 12.9 certainly correspond to the structurally related SAPO-47 (CHA), which has been synthesized using n-propylamine as single SDA recently (Xu et al. 2015, 123-128). SAPO-47 belongs to the CHA-like SAPO-solids, such as SAPO-44 and the much more common SAPO-34 (CHA). (T. Wang et al. 2010, 138-147).

[0089] [FIG. 1]

[0090] The purity of the SAPO-56 according to the present invention synthesized with a ratio of 70% IPA: 30% TMHD was evaluated. FIG. 2 displays XRD patterns formed at crystallization times of 48-114 h. From the differences it could be observed that SAPO-56 crystallized at short crystallization times (48 h) then the fraction of co-crystallized SAPO-47 increased with time. It appeared clear that 48 h was the preferred crystallization duration and 210 the preferred temperature. The mechanism for the co-crystallization of SAPO-47 is not fully clear, and it appears as further studies need to be performed to corroborate various hypotheses (for example SAPO-56 crystallites dissolution and recrystallization of SAPO-47). The occurrence of two crystalline phases during the synthesis of SAPO-56 using co-SDA has being reported, but not for the SAPO-47 (CHA). For example Cao and Shan et al. 2012 (Cao and Shah 2011) reported the intergrown of SAPO-56 (AFX) and SAPO-(CHA), using TMHD and N,N-dimethylcyclohexylamine as co-templates. While (Turrina et al. 2016, 4998-5012) reported SAPO-17 (ERI) and SAPO-34 (CHA) using 1,4-(1,4-diazabicyclo[2.2.2]octane)butyldibromide and trimethylamine. Recently (D. Wang et al. 2016, 1000-1008) reported the synthesis of SAPO-34 (CHA) and SAPO-56 using triethylamine and trimethylamine; however, they used HF as a mineralizer, which has it defined problems when it comes to upscaling.

[0091] [FIG. 2]

[0092] Also using a significant amount of IPA 70 molar % (44.5 weight %), FIG. 3 shows the effect of crystallization temperature on the SAPO phase obtained using similar gel conditions as in FIG. 2. The SAPO-47 was obtained at low temperatures 180 to 190 C., while the SAPO-56 started to co-crystallize at a temperature of 200 C. The addition of seeds did not influence the formation of SAPO-56 phase at a low temperature; however the crystals of SAPO-47 adopted the morphology (SEMs shown in FIG. 14) of SAPO-56 as was discussed above.

[0093] [FIG. 3]

[0094] The stability of the crystalline structure of SAPO-56 after SDA removal was demonstrated by the XRD diffactograms presented in FIG. 4. Note, that a complete SDA removal and its sub-products appears to occur at as a high temperature as 720 C., as was corroborated by TGA (data not shown).

[0095] [FIG. 4]

[0096] Gas adsorption performance tests were performed. The CO.sub.2 and CH.sub.4 adsorption isotherms were recorded at temperature of 0 C. FIG. 10 show a high CO.sub.2 adsorption capacity of 4.15 mmol/g and CH.sub.4 adsorption capacity of 1.12 mmol/g at 101 kPa. The estimated selectivity is 6.0 using the simple model (V1/V2)/(p1/p2) for a 50%/50% CO.sub.2/CH.sub.4 gas mixture that simulate the biogas composition used for upgrading. This selectivity value is comparable to the reported by (Bacsik et al. 2016a, 613-621) for SAPO-56 and tested also here (FIG. 20) surpasses those of ALPO-17, activated carbon and metal organic framework.

[0097] [FIG. 5]

[0098] [FIG. 6]

[0099] [FIG. 7]

[0100] [FIG. 8]

[0101] [FIG. 9]

[0102] [FIG. 10]

[0103] [FIG. 11]

[0104] [FIG. 12]

[0105] [FIG. 13]

[0106] [FIG. 14]

[0107] [FIG. 15]

[0108] [FIG. 16]

[0109] [FIG. 17]

[0110] [FIG. 18]

[0111] [FIG. 19]

[0112] [FIG. 20]

[0113] [FIG. 21]

[0114] Further Experimental Data:

[0115] Additional Synthesis of Seeds of SAPO-56

[0116] Regular SAPO-56 was crystallized from gels with a starting molar composition of 2.1 TMHD: 0.9 SiO.sub.2: 0.8 Al.sub.2O.sub.3: 1 P.sub.2O.sub.5: 50 H.sub.2O. In a typical procedure, 9 g of distilled water, 2.2 g of phosphoric acid (85 wt. % in water, Sigma Aldrich) and 1.1 g of pseudoboehmite (Aluminum Corporation of China, Shandong) were added to a polypropylene vessel, which was closed and vigorously stirred for 2 h at room temperature. After this, 1 mL of a LUDOX HS-40 colloidal silica (40 wt. % suspension in water containing stabilizing Na.sup.+ at pH equal to 9.8, Sigma Aldrich) was added, and the mixture was stirred for 1 h. Finally, 3.45 g of TMHD (99% Sigma Aldrich) was added under vigorous mixing for 24 h. On the addition of TMHD, the temperature increased temporarily, and the mixture thickened. The gel was transferred to 100 mL-sized and Teflon-lined stainless-steel autoclaves and was heated at 190-210 C. for 2-4 days. The solid and liquid phases were recovered and separated by decantation. The yellow and gelatinous phase top phase was discarded, while the white solid phase was thoroughly washed with an excess of distilled water (resuspension and centrifugation cycles of 6000 rpm for 5 min) and dried in a conventional oven at a temperature of 80 C. overnight. Sample calcination was performed at 650 C. for 12 h to remove the SDA.

[0117] In addition to the LUDOX HS-40 colloidal silica, we synthesized SAPO-56 using fumed silica (0.2-0.3 m aggregates, pH of 3.6 to 4.3 at 40 g/L, Sigma Aldrich) in similar manner. It was added in similar molar ratios and method described.

[0118] Synthesis of SAPO-56 Using Additional Co-SDAs

[0119] SAPO-56 was crystallized with the SDA and co-SDAs by using a starting gel with molar compositions of 2.1 (SDA+co-SDA): x SiO.sub.2: y Al.sub.2O.sub.3: z P.sub.2O.sub.5: 50 H.sub.2O with a similar preparation procedure as was described under the additional synthesis of seeds of SAPO-56. The (Al+P)/Si.sub.gel ratio is defined as 2y+2z/x. The co-SDA were primary (IPA, purity >99.5% Sigma Aldrich), secondary (DBA, purity >99.5% Sigma Aldrich) and tertiary amines (TPA, purity >98% Sigma Aldrich). Synthetic details are presented in the Tables 5. Seeds of as-synthesized SAPO-56 (prepared with TMHD) was added to the gels immediately after the SDA and co-SDA under vigorous stirring. The gels were aged for 24 h, transferred to Teflon-lined stainless-steel autoclaves, and heated at 200-210 C. for 2-4 days. The white solid products were recovered and thoroughly washed with an excess of distilled water (resuspension and centrifugation cycles of 6000 rpm for 5 min) and dried in a conventional oven at a temperature of 80 C. overnight. Sample calcination was performed at 650 C. for 12 h to remove the SDA and co-SDA.

[0120] Characterization of the Silicoaluminophosphate SAPO-56 of the Further Experimental Data

[0121] X-ray diffraction patterns of the as-synthesized products were recorded on an X'Pert alpha 1 P analytical diffractometer using Cu-K radiation and a PIXCEL detector, in the 2 range of 5-40.

[0122] Scanning electron microscopy (SEM) images were captured with a JEOL JSM-7000F microscope using a working distance of 10 mm, and voltage of 5 to 15 kV. As-synthesized and powders were spread on carbon-coated aluminum holders before SEM experiments were conducted. Elemental analysis was performed over a number of particles by using an INCA Energy Dispersive X-ray Spectroscopy detector (EDS) at 15 kV, and quantification was performed with the INCA Microanalysis Suite v4.15. Average particle sizes were estimated from the SEM images with the ImageJ software. At least 20 particles from three different areas of each sample were counted.

[0123] Thermogravimetric analysis (TG) and derivative thermogravimetric analysis (DTG) was performed in technical air with a Discovery TGA-TA Instruments analyzer using an airflow of 20 mL/min and heating rate of 10 C/min.

[0124] Solid-state {.sup.1H}.sup.13C Nuclear Magnetic Resonance (NMR) spectra were recorded in a 4-mm probe head under Magic Angle Spinning (MAS) of 14 kHz on a 600 MHz Bruker Avance III spectrometer (with a wide-bore magnet). A ramped crosspolarization with a contact time of 1.6 ms was used for the transfer of the .sup.1H.sup.13C magnetization, and SPINAL decupling of the.sup.1H magnetization was used during the detection of the .sup.13C transients. For each spectrum, 5120 transients were acquired. A small amount of exponential apodization was applied to the free induction decay before Fourier transformation, and the .sup.13C chemical shift scale was externally calibrated to the methine shift of 38.6 ppm of adamantane.

[0125] N.sub.2, CO.sub.2 and CH.sub.4 Adsorption for Samples from the Further Experimental Data

[0126] Gas adsorption tests were performed on a Micromeritics ASAP2020 surface area and porosity analyzer, and the calcined sample was subjected to dynamic vacuum at a temperature of 350 C. (heating rate 10 C/min) for 6 h. The sample was backfilled to 101 kPa with N.sub.2 before recording of the N.sub.2, CO.sub.2 and CH.sub.4 isotherms.

[0127] CO.sub.2 and CH.sub.4 adsorption data were recorded at 0 C. up to an absolute pressure of 101 kPa. The temperature was set by an ice bath. The data points were recorded when the pressure change was less than 0.01% during a 10 s interval. While, N.sub.2 adsorption data were recorded at 196 C. and the temperature was set by a liquid nitrogen bath. The data were analyzed using MicroActive Interactive Data Analysis software.

[0128] The Brunauer-Emmett-Teller (BET) surface area was calculated at relative pressure 0.0001-0.05 and based on the criterion of linearity of the plot Q(1P/P.sub.0) vs P/P.sub.0. .sup.33 The micropore volume was calculated from the N.sub.2 isotherm using t-plot method, and the ultramicropore volume from CO.sub.2 isotherm was estimated by using a CO2-DFT model derived for slit-like carbon-based materials.

TABLE-US-00005 TABLE 5 Gel composition (molar basis) 1.7-2.1 TMHD, co-SDA: x SiO.sub.2: y Al.sub.2O.sub.3: z P.sub.2O.sub.5: 40-55 H.sub.2O, experimental conditions for the synthesis of SAPO-56 and complementary data from the literature. Temperature Time Crystalline Sample TMHD x y z H.sub.2O (Al + P)/Si.sub.gel Seed ( C.) (h) phase This work 2.10 0.91 0.82 1 52 4 NO 210 95 SAPO-56 S-4 This work 2.10 1.9 0.86 1 55 1.95 NO 210 95 SAPO-56 S-5 This work 2.10 0.64 0.82 1 53 5.7 NO 210 95 SAPO-56 S-9 This work 1.76 0.76 0.69 1 44 4.45 YES 190 47 SAPO-56 S-46 This work 1.77 0.77 0.70 1 44 4.43 YES 200 48 SAPO-56 S-72 25 1 0.60 1.00 1 40 6.66 200 96 SAPO-56 20 2 0.60 0.80 1 40 6.00 200 96 SAPO-56 17 2 0.60 0.80 0.5 50 4.30 200 60 SAPO-56 36 2 0.60 0.80 1 50 6.00 200 48 SAPO-56 Sample B 36 2 0.92 0.72 0.72 50 3.13 200 48 SAPO-56 Sample C 37 2 0.60 0.80 1 200 6.00 210 48 SAPO-56 Sample c 37 2 0.60 0.80 1.4 200 7.33 200 24 SAPO-56 Sample i TMHD means N,N,N,N-tetramethyl-1,6-hexanediamine

TABLE-US-00006 TABLE 6 Surface area and (ultra)micropore volume of SAPO-56 synthesized with TMHD and TMHD: co-SDAs. BET specific surface Pore volume (cm.sup.3/g) Uptake of Uptake of Phase areas Ultramicropore Micropore by CO.sub.2 CH.sub.4 Sample SDA:co-SDA (s) (m.sup.2/g) by DFT method.sup.b t-plot .sup.d (mmol/g) (mmol/g) S-4 100% TMHD SAPO-56 2.97 97E5 0.11 0.05 S-72 100% TMHD SAPO-56 451 0.15 0.17 4.73 1.08 S-26 100% TMHD SAPO-56 + 0.08 2.69 0.59 SAPO-20 S-17 50% TMHD:50% IPA SAPO-56 + 644 0.17 0.25 5.35 1.23 SAPO-47 S-78 50% TMHD:50% DBA SAPO-56 + 731 0.14 0.28 4.61 1.04 SAPO-17 S-33 60% TMHD:40% TPA SAPO-56 715 0.12 0.27 4.29 1.02

[0129] [FIG. 22]

[0130] [FIG. 23]

[0131] [FIG. 24]

[0132] [FIG. 25]

[0133] [FIG. 26]

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