Adsorption of Ethane and Ethylene over 3D-Printed Ethane-Selective Monoliths

Abstract

The use of paraffin-selective adsorbents in separation of paraffin/olefin pairs has been recently demonstrated as a sustainable platform for recovering a highly pure olefin product directly from the adsorption step. These materials allow for development of a less expensive and economically attractive technology for olefin/paraffin separation. Herein, we report formulation of paraffin-selective adsorbents into monolithic contactors and evaluation of their adsorptive performance in ethane/ethylene separation. More specifically, Ni(bdc)(ted) 0.5 and ZIF-7 were used as ethane-selective adsorbents for development of monoliths via 3D printing. Their formulation was optimized according to printability of the extruded paste and mechanical stability of the final monolith piece. Through equilibrium and dynamic adsorption experiments, it was demonstrated that formulation of the adsorbents into monoliths does not adversely affect their separation efficiency, and the monoliths exhibit uptakes proportional to the adsorbent loading and comparable to those of their powder analogues. Application of the ideal adsorption solution theory method predicted C 2 H 6 /C 2 H 4 selectivities in the ranges 1.9−11.8 and 1.2−2.0 for ZIF-7 and Ni(bdc)(ted) 0.5 monoliths, respectively. The findings of this study highlight the feasibility of 3D printing as a facile and cost-effective approach in shaping paraffin-selective adsorbents into practical contactors.

Synthesis through 3D printing: formation of 3D coordination polymers

“…Thakkar et al reported the 3D-printing of MOF, embedded in an organic-inorganic binder for removal of CO 2 from air, 15 as well as the 3D-printing of ZIF-7 embedded within organic monoliths for ethane/ethylene separation processes. 16 Our group reported the 3D-printing of Cu-BTC MOF for the adsorption of organic dyes from solutions, 17 and Lyu et al reported a 3D-printed cobalt-based MOF embedded within an organic binder for energy storage applications. 18 More examples on 3D-printed MOFs were explored by Lawson et al and Sultan et al 19,20 Recently, our group, in collaboration with Amo-Ochoa and Zamora, also published the 3D-printing of a Cu 2+ coordination polymer for the colorimetric sensing of humidity and water.…”

New Promises and Opportunities in 3D Printable Inks Based on Coordination Compounds for the Creation of Objects with Multiple Applications

“…Their possible use on an industrial scale implies transformation into monoliths to improve the performance compared with that of traditional bead or pellet forms, allowing separations at lower pressures or temperatures. Thakkar et al [44b] . used DIW to 3D print these materials by dissolving Ni‐BT in ethanol at 60 °C, 2 h, and PVA in DMSO was slowly added to this solution.…”

“…In the latter case, the ZIF‐7 powder took 15 min to reach the same degree of saturation. ZIF‐7‐M presents stronger interactions with the adsorbed gases due to higher adsorption heats [44b] …”

Rapid fabrication of MOF-based mixed matrix membranes through digital light processing

“…8,9 From this perspective, metal-organic frameworks (MOFs) are promising filler candidates. [10][11][12][13][14][15] Conceptually, the integration of a MOF component into additive formulations has been approached and then realized through different 3D printing techniques 4 -inkjet, 16,17 direct ink writing (DIW), [18][19][20][21][22][23][24][25][26][27] fused deposition modelling (FDM), [28][29][30] digital light processing (DLP) 31 and selective laser sintering (SLS). 32,33 For instance, photoluminescent lanthanide MOFs-based inks for inkjet printing were reported by da Luz et al 16 In addition to examples of MOF coatings grown on 3D printed objects obtained by stereolithography (SLA) 34 or direct ink writing, 24 fabrication of monoliths with full integration of the MOF component within a melting matrix of acrylonitrile butadiene styrene (ABS), 28,29 poly(lactic acid) (PLA) or polyurethane (TPU) thermoplastics 30 have been achieved using fused deposition modelling.…”

“…28 Unlike in the FDM approach, firm monoliths with accessible internal porosity, suitable for applications involving adsorption, have been obtained via direct ink writing. Moreover, several representative examples of composites with high MOF loading 22 suitable for gas separation, 18,20,21 catalysis, 26 molecule sequestration and release have been reported. 19,25 Similarly, tailored shapes with †Electronic Supplementary Information (ESI) available: Chemical schemes of commercial oligomers; tables with inks formulation composition; DLP 3D printed details and specifications; additional figures; N 2 and Ar adsorption data and plots; TEM images and particle size distribution histograms; NMR data and plots; FTIR; viscosity data; ATR-IR, kinetic data of photopolymerization in systems with and without MOF additive; Raman spectra and mapping; mechanical data; optic microscope images; SEM-EDX maps; data on degree of crosslinking; TG and DSC analyses; gas separation performance data.…”