Two types of zeolites (type X and type A) were synthesized from fly ash of two Brazilian coal based power plants via hydrothermal treatment after ash fusion with NaOH. The synthesized zeolites were characterized by means of XRF, XRD, SEM and gas adsorption (N₂ and CO₂ adsorption/desorption at − 196 and 0 °C, respectively). Pure CO₂ and N₂ adsorption equilibrium isotherms were performed at 50, 70 and 90 °C to measure the CO₂ adsorption capacity and selectivity of CO₂ over N₂. CO₂/N₂ binary isotherms (15/85% v/v) were also obtained at the same temperatures. Commercial zeolitic materials used for CO₂/N₂ separation such as zeolite 13X and zeolite 4A underwent the same characterization and adsorption measurements as benchmarks to evaluate the performance of the synthesized zeolites. The synthesized materials from fly ash are promising low cost adsorbents for CO₂ separation, reaching ca. 83% of the CO₂ adsorption capacity of their commercial counterparts at 0.15 bar and 50 °C.

在与NaOH进行灰分熔融后，通过水热处理将两种巴西煤电厂的粉煤灰合成为两种沸石（X型和A型）。通过XRF，XRD，SEM和气体吸附（分别在-196和0°C下的N ₂和CO ₂吸附/解吸）表征合成的沸石。在50、70和90°C下进行纯CO ₂和N _2的吸附平衡等温线，以测量CO _2的吸附容量和CO ₂对N _2的选择性。在相同温度下也获得了CO ₂ / N ₂二元等温线（15/85％v / v）。用于CO的商业沸石材料₂ / N ₂分离（如13X沸石和4A沸石）进行了与基准相同的表征和吸附测量，以评估合成沸石的性能。由粉煤灰合成的材料有望成为用于CO ₂分离的低成本吸附剂，可达到约。在0.15 bar和50°C的条件下，它们的商用同行对CO _2的吸附能力为83％。