Ob-Eye Jeerati, Wanmolee Wanwitoo, Boonyoung Pawan, Praserthdam Piyasan, Jongsomjit Bunjerd
Center of Excellence on Catalysis and Catalytic Reaction Engineering (CECC), Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand.
Bio-Circular-Green-Economy Technology & Engineering Center, BCGeTEC, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand.
Environ Technol. 2024 Aug 16:1-16. doi: 10.1080/09593330.2024.2390151.
In this study, the efficiency of a series of biochar-supported Cu catalysts, biochar-supported Zn catalysts, and biochar-supported Cu-Zn catalysts was determined through bioethanol dehydrogenation to the high-value chemical, acetaldehyde. Each metal, with weight percentages of 10, 20, and 30, and the combination of Cu-Zn, including 10 wt% of Cu and Zn, 15 wt% of Cu - 5 wt% of Zn, and 15 wt% of Cu and Zn, were fully loaded onto biochar using an incipient wetness impregnation technique. Subsequently, all biocatalysts were subjected to bioethanol dehydrogenation reactions in a temperature range of 200-400 °C. The optimum metal loading for the catalyst was found to be the combination of 15 wt% Cu and 15 wt% Zn. This catalyst resulted in a reasonable acetaldehyde yield of 56.2%, an initial bioethanol conversion of 57.3%, and a very high acetaldehyde selectivity of 98.1% at a mild reaction temperature of 300 °C and ambient pressure. These results were attributed to the optimal concentration of weak-medium acid and medium base sites. Active acid and base sites were identified through temperature-programmed desorption of ammonia (NH-TPD) and temperature-programmed desorption of carbon dioxide (CO-TPD), respectively. Furthermore, the reaction stability test of the best biocatalyst (15Cu-15Zn/BB) was proven by maintaining this reaction at the same temperature (300 °C) for 10 h. However, the catalytic performance slightly decreased due to the coke formation of Cu species.
在本研究中，通过生物乙醇脱氢生成高价值化学品乙醛，测定了一系列生物炭负载的铜催化剂、生物炭负载的锌催化剂以及生物炭负载的铜锌催化剂的效率。使用初湿浸渍技术将重量百分比分别为10%、20%和30%的每种金属以及铜锌组合（包括10 wt%的铜和锌、15 wt%的铜 - 5 wt%的锌以及15 wt%的铜和锌）完全负载到生物炭上。随后，所有生物催化剂在200 - 400 °C的温度范围内进行生物乙醇脱氢反应。发现催化剂的最佳金属负载量为15 wt%的铜和15 wt%的锌的组合。在300 °C的温和反应温度和常压下，该催化剂产生了56.2%的合理乙醛产率、57.3%的初始生物乙醇转化率以及98.1%的非常高的乙醛选择性。这些结果归因于弱 - 中强酸和中强碱位点的最佳浓度。分别通过氨程序升温脱附（NH - TPD）和二氧化碳程序升温脱附（CO - TPD）确定了活性酸和碱位点。此外，可以通过在相同温度（300 °C）下将该反应维持10小时来证明最佳生物催化剂（15Cu - 15Zn/BB）的反应稳定性。然而，由于铜物种的积炭，催化性能略有下降。
