Synthesis of ZIF‐94 from Recycled Mother Liquors: Study of the Influence of Its Loading on Postcombustion CO₂ Capture with Pebax Based Mixed Matrix Membranes

Abstract

and unpredictable climatic changes such as rising sea levels, melting of glaciers throughout the entire planet [2] and affecting agriculture, [3] to name a few.A release of greenhouse gases will continue if no action is taken either for searching of green energy sources or filtering postcombustion gases to limit the global temperature rise below 2 °C (which was established during Paris conference in 2015). [4] Carbon capture and storage (CCS) is one of the methods of purification of flue gas after capturing CO 2 being a straightforward solution to avoid concerned challenges. There are several possible technologies for CCS either based on solvents (absorption), solid adsorbents (adsorption), cryogenic process or membrane-based approach. Even though chemical solvent treatment (especially by amines), physical absorption, and cryogenic separation are very effective methods, they are characterized by high vapor pressure and emission of toxic compounds. Moreover, it is very difficult to recycle them mainly due to the high reaction heat. [2,5] Membrane-based technology, a fast growing and environmental-friendly separation process, has the potential to replace conventional energy-intensive technologies and provides reliable solutions for CCS. This is mainly due to the low energy consumption linked to membranes, operation flexibility and simplicity, good stability, easy control and scale-up. Typically, polymeric membranes are used for the gas separation thanks to a solution-diffusion mechanism that benefits from the intrinsic property of the material for the gas transport. However, such membranes are bounded by their performance, known as the Robeson upper bound, [6] where gas permeability is sacrificed for gas mixture selectivity and vice versa. Moreover, higher membrane surface area is required for the expected separation to be industrially attractive.A class of polymeric composite membranes named mixed matrix membranes (MMMs) with specific fillers coupled with other existing processes (cryogenic/absorption) could be the best technology for CO 2 capture. MMMs are made of a base polymeric matrix and a compatible inorganic micro/nanosized filler that is integrated inside the micropores of polymeric materials to improve their properties. [7] In fact, the filler contributes to favor the permeability of the desired component in the mixture through the modification of the diffusivity and solubility Global energy demand is met in large part, by burning of fossil fuels, which is causing global warming. Mixed matrix membranes (MMMs) with metal organic frameworks (MOFs) as fillers are an interesting alternative for capturing post combustion CO 2 which would make the energy sector sustainable. This research is focused on the synthesis of MOF ZIF-94 from the recycling of its mother liquors and the incorporation of synthesized MOF into a Pebax MH 1657 for MMM fabrication. The pH and the temperature of ZIF-94 synthesis are modified and monitored and this results in various nanoparticle diameters (average particle size in the range of...

A facile route for the recovery of the ligand of zeolitic imidazolate framework ZIF-94/SIM-1

“…3 In addition, the present study completes some of the recent attempts ( e.g. recycling solvents and reagents from the synthesis or spent mother liquors 12–17 in line with the high environmental impact of organic solvents in the MOF synthesis 18 ) to make the synthesis of MOFs more sustainable, none of them dealing with the dissolution of the MOF to purify and reuse its ligand. The reuse of this ligand from discarded ZIF-94/SIM-1 crystals would save an important part of the energy and resources needed to produce new ligand.…”

“…S1 (ESI †), all 1 H signals are practically the same for the recovered imidazole ligand and the as-received commercial one. The corresponding assignation, confirmed by 1 H- 13 C HSCQ (Fig. S2, ESI †), is shown in Table 1.…”

The Atomic Structure and Mechanical Properties of ZIF-4 under High Pressure: Ab Initio Calculations

“…Zeolitic imidazolate frameworks (ZIFs) are a unique class of porous hybrid materials known as a subset of metal-organic frameworks (MOFs), and have been studied extensively over the past decade due to their potential applications in gas sorption and separation, catalysis, drug delivery, and sensing applications [1][2][3][4][5]. Especially in the field of environmental protection, ZIFs and their composite structures have also shown considerable potential in research into the capture of greenhouse gases recently [6][7][8][9]. The ZIF structure consists of tetrahedral metal ions, typically Zn 2+ or Co 2+ , linked by organic bridging ligands, which are derived from imidazolate anions (Im = C 3 N 2 H 3 − ) [10].…”

Highly stable Pebax® Renew® thin-film nanocomposite membranes with metal organic framework ZIF-94 and ionic liquid [Bmim][BF4] for CO2 capture

“…In this case, the BET SSA decreases from 1350 cm 2 g −1 for the ZIF-8 to 464 cm 2 g −1 for the ZIF-94 (OR) and to 645 cm 2 g −1 for the ZIF-94 (SALE), which is in accordance with the literature for synthesized ZIF-94 particles. 47,49 However, these values suggest that the conversion of ZIF-8 into ZIF-94 was high but not complete with a remain of the ZIF-8 composition responsible for the larger value of BET SSA for ZIF-94 (SALE) as compared to that of the as-made ZIF-94. Furthermore, Fig.…”