Table_Figure1

This gives the population phenological estimates according to population elevations used in Figure 1

FAU-Type Zeolite Nanocasted Carbon Replicas for CO₂ Adsorption and Hydrogen Purification

Microporous ordered carbon have been synthesized by the nanocasting process from zeolite Y using acetylene and furfuryl alcohol as carbon precursors. If the proper synthesis conditions are chosen, these materials retain the long-range order of the zeolite mold. The resulting carbons possess a large surface area (≥2200 m²/g), a high microporosity (≥1.0 cm³/g), and a controlled pore size distribution, which was tailored by the wall thickness of the zeolite template. Because of their high micropore volume, the carbon replicas of zeolite Y are attractive adsorbent materials and might be used to replace conventional activated carbons as adsorbents in pressure swing adsorption processes (PSAs) for H₂ purification. In the present contribution, we evaluate the adsorption capacity of the carbon replicas in a H₂-PSA based on their single-component adsorption isotherms of CO₂, CH₄, and N₂ measured at room temperature. The ideal adsorbed solution theory (IAST) was used to predict the co-adsorption of CO₂/CH₄/N₂ gas mixtures and to evaluate the working capacity of the materials under typical operating conditions of a H₂-PSA process. The comparison of the working capacities shows that the carbon replicas largely outperform conventional activated carbons while having comparable CO₂/CH₄ and CO₂/N₂ selectivity

Structure and Sorption Properties of a Zeolite-Templated Carbon with the EMT Structure Type

An ordered microporous carbon material was prepared by the nanocasting process using the EMC-2 zeolite (EMT structure type) as a hard template. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed long-range ordering in the material that resulted from the negative replication of the host template. The carbon porous network replicating the zeolite structure was modeled by overlapped spherical voids with diameters determined from the XRD pattern that displayed up to six distinct peaks. The surface delimiting the 3D interconnected porosity of the solid has a complex morphology. The pore size distribution calculated from the XRD-derived structural model is characterized by a maximum at 1.04 nm related to the long-range-ordered microporous network. Complementary studies by immersion calorimetry revealed that most of the porosity was characterized by a size above 1.5 nm. These porous features were compared to data resulting from classical analysis (DR, DFT, BET, etc.) of the N₂ (77 K) and CO₂ (low and high pressure, 273 K) physisorption isotherms. The limitations of these approaches are discussed in light of the pore size distribution consistently determined by XRD and immersion calorimetry measurements