Chemical Engineering Group, Engineering and Technology Institute Groningen (ENTEG), Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
DMT Environmental Technology, Yndustrywei 3, 8501 SN Joure, The Netherlands.
Molecules. 2023 Feb 27;28(5):2198. doi: 10.3390/molecules28052198.
Biomethane can be isolated from biogas through selective CO adsorption. Faujasite-type zeolites are promising adsorbents for CO separation due to their high CO adsorption capacity. While commonly inert binder materials are used to shape zeolite powders into the desired macroscopic format for application in an adsorption column, here we report the synthesis of Faujasite beads without the use of a binder and their application as CO-adsorbents. Three types of binderless Faujasite beads (d = 0.4-0.8 mm) were synthesized using an anion-exchange resin hard template. All the prepared beads consisted mostly of small Faujasite crystals, as demonstrated by characterization with XRD and SEM, which are interconnected through a network of meso- and macropores (10-100 nm), yielding a hierarchically porous structure, as shown by N physisorption and SEM. The zeolitic beads showed high CO adsorption capacity (up to 4.3 mmol g at 1 bar and 3.7 mmol g at 0.4 bar) and CO/CH selectivity (up to 19 at the partial pressures mimicking biogas, i.e., 0.4 bar CO and 0.6 bar CH). Additionally, the synthesized beads have a stronger interaction with CO than the commercial zeolite powder (enthalpy of adsorption -45 kJ mol compared to -37 kJ mol). Therefore, they are also suitable for CO adsorption from gas streams in which the CO concentration is relatively low, such as flue gas.
沼气可以通过选择性 CO 吸附从生物气中分离出来。由于具有较高的 CO 吸附能力，方钠石型沸石是分离 CO 的有前途的吸附剂。虽然通常使用惰性粘结剂材料将沸石粉末成型为所需的宏观形状，以应用于吸附柱中，但在这里我们报告了不使用粘结剂合成方钠石珠体及其作为 CO 吸附剂的应用。使用阴离子交换树脂硬模板合成了三种无粘结剂方钠石珠体（d = 0.4-0.8 毫米）。所有制备的珠体主要由小方钠石晶体组成，这通过 XRD 和 SEM 表征得到证实，这些晶体通过介孔和大孔（10-100nm）的网络相互连接，形成了分级多孔结构，这通过 N 物理吸附和 SEM 得到证实。沸石珠体表现出高的 CO 吸附容量（在 1 bar 时高达 4.3 mmol g，在 0.4 bar 时高达 3.7 mmol g）和 CO/CH 选择性（在模拟沼气的分压下高达 19，即 0.4 bar CO 和 0.6 bar CH）。此外，与商用沸石粉相比，合成的珠体与 CO 的相互作用更强（吸附焓-45 kJ mol 与-37 kJ mol）。因此，它们也适用于从 CO 浓度相对较低的气流中（例如烟道气）吸附 CO。
