Aleixo Fábio C, Faria Diêgo N, Fernández Joycel V, Cipriano Daniel F, Rodrigues José G A, Brito Gilberto M, Schettino Miguel A, Bolsoni Amanda, Brandão Geisamanda P, Silveira Leonardo L L, Freitas Jair C C
Laboratory of Carbon and Ceramic Materials, Department of Physics, Federal University of Espírito Santo, Vitória, Espírito Santo 29075-910, Brazil.
Laboratory of Chemical Sciences, State University of the Northern Rio de Janeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil.
ACS Omega. 2025 Jul 15;10(29):31536-31548. doi: 10.1021/acsomega.5c02065. eCollection 2025 Jul 29.
This work describes the optimization of the synthesis of carbon-supported heterogeneous catalysts containing CaO and MgO derived from ornamental stone waste (OSW) in view of their use for biodiesel production. The catalysts were prepared by mixing the OSW and coconut shell activated carbon (CSAC) powders with a NaOH solution under constant stirring; the mixture was then subjected to thermal treatments in an inert atmosphere. The variables of the synthesis process (thermal treatment temperature, residence time, and OSW/CSAC mass ratio) were analyzed using 2 full factorial designs; the response variable was the biodiesel conversion, monitored by solution H nuclear magnetic resonance (NMR) spectroscopy. The presence of the phases CaO, MgO, NaCO, NaCa-(CO), and Ca-(OH) (in amounts depending on the synthesis conditions) was identified by X-ray diffraction and solid-state Na NMR. The biodiesel conversion varied between 47 and 85%, with the highest value corresponding to the catalyst prepared using an OSW/CSAC mass ratio of 50:20 and thermally treated at 800 °C for 1 h. The main benefit of using the porous carbon support for the catalytically active phases was the significant reduction in the number of metals leached into the produced biodiesel.
这项工作描述了从观赏石废料（OSW）中合成含CaO和MgO的碳载多相催化剂的优化过程，旨在将其用于生物柴油生产。通过在持续搅拌下将OSW和椰壳活性炭（CSAC）粉末与NaOH溶液混合来制备催化剂；然后将混合物在惰性气氛中进行热处理。使用2个全因子设计分析合成过程的变量（热处理温度、停留时间和OSW/CSAC质量比）；响应变量是生物柴油转化率，通过溶液H核磁共振（NMR）光谱监测。通过X射线衍射和固态Na NMR鉴定了CaO、MgO、NaCO、NaCa-(CO)和Ca-(OH)相的存在（其含量取决于合成条件）。生物柴油转化率在47%至85%之间变化，最高值对应于使用50:20的OSW/CSAC质量比制备并在800°C下热处理1小时的催化剂。使用多孔碳载体作为催化活性相的主要好处是显著减少了浸出到生产的生物柴油中的金属数量。
