金屬改質沸石與奈米鈦管對低濃度二氧化碳吸附/脫附效能研究

Abstract

由於人類大量的活動及工業發展，造成大氣中的二氧化碳濃度逐年攀升，至今成為全球熱門的環境議題，而文獻研究指出若提高溫室中的二氧化碳濃度，將有效提升農作物之生長。因此，本研究將模擬捕獲大氣中的二氧化碳，進行循環吸脫附濃縮測試。於研究中首先探討金屬改質前後沸石之吸脫附效能，結果顯示經鋰金屬改質後的沸石具有最佳的吸附效能，於二氧化碳濃度為400ppmv時其吸附容量可達13.3mg/g，但脫附效能卻低於13X與10X沸石。而在探討大氣濕度環境下之吸附實驗結果顯示，沸石材料13X與10X於乾燥空氣下(RH=8%)進行400ppmv二氧化碳之吸附實驗，其吸附量皆可達10mg/g左右之吸附容量，相較於高濕度環境下(RH=60%、80%)為2mg/g的吸附容量來的高。另一方面，Na-TNT則表現出相反之特性，在高濕度環境下二氧化碳吸附量為4.3mg/g，大於乾燥空氣環境下的吸附量2.6mg/g，在高濕度下Na-TNT之抗水氣能力亦優於13X與10X沸石材料，因此較適合作為實際大氣環境濕度條件下使用。

The increasing concentration of carbon dioxide (CO2) in the atmosphere is an environmental concerned issue. However, literature data indicated that increasing CO2 concentration inside the greenhouse will be benefitial for greenhouse plantation. Thus in this study CO2 capture from the atmospheric condition by cyclic adsorption-desorption processes is evaluted. The CO2 adsorption capacities of metal modified zeolites are compared to zeolites 13X and 10X. Results on breakthrough tests showed that LiX has the best adsorption capacity of 13.3mg/g at CO2 concentration of 400ppmv. But its desorption efficiency is worse than those of 13X and 10X zeolites. On the other hand, CO2 capture under different moisture contents shoewd the adsorption capacity of 13X and 10X are approximately 10mg/g at 8% RH, which is better than that at RH=80% (2mg/g). The alkali metal titanate nanotubes was the material which has the advantage of better CO2 adsorption capacity at higher humidity condition. At 80% RH the adsorption capacity of Na-TNT was 4.3mg/g, better than that under dry condition of RH=8% (2.6mg/g). The titaniate nanotubes revealed better water tolerance than the zeolites type materials.