Sales H B, Oliveira M S, Silva A L, Pereira H L, Costa A C F M, Alves M C F
Laboratory of Ceramic Materials Synthesis (LabSMac), Graduate Program in Materials Science and Engineering (PPGCEMat), Academic Unit of Materials Engineering (UAEMa), Federal University of Campina Grande (UFCG), Rua Aprígio Veloso, 882, Bodocongó, 58.429-900, Campina Grande, PB, Brazil.
Laboratory of Inorganic Materials for Environmental Catalysis Research, Department of Chemistry (MATIPECA), Graduate Program in Chemistry (PPGQ), DQ , State University of Paraíba (UEPB), Rua Baraúnas, 351, Universitário, 58.429-500, Campina Grande, PB, Brazil.
Sci Rep. 2025 May 31;15(1):19152. doi: 10.1038/s41598-025-03863-2.
This study aimed to explore the use of ornamental stone waste as a support for the α-MoO₃ catalyst to develop efficient and sustainable heterogeneous systems for biodiesel production. The catalysts were characterized using physicochemical techniques including X-ray diffraction with Rietveld refinement, FTIR and Raman spectroscopy, scanning electron microscopy with EDS, transmission electron microscopy, nitrogen adsorption/desorption (BET method), particle size distribution, ammonia temperature-programmed desorption (TPD-NH₃), magnetic measurements, and gas chromatography to analyze simultaneous transesterification/esterification (TES) reactions and quantify methyl and ethyl esters. XRD patterns revealed crystalline phases such as mica-biotite, ferro-tschermakite, albite, quartz, and iron-magnesium silicates-components of the catalytic support-as well as orthorhombic α-MoO₃ phases, also confirmed in the heterogeneous systems. FTIR and Raman analyses showed characteristic vibrational bands, while SEM images displayed irregular agglomerates, corroborated by TEM. Nitrogen adsorption isotherms indicated mesoporous structures with surface areas ranging from 0.615 to 3.87 m²/g. Particle size analysis showed D₅₀ values between 5.02 and 20.00 μm, with total acidity ranging from 77.0 to 245 µmol/g of NH₃. Magnetic tests indicated ferrimagnetic behavior. The catalytic performance confirmed the effectiveness of the waste as a support for α-MoO₃, particularly in the system containing 40% Mo ions (40%σ-MoO₃:Waste), which achieved conversions between 78% and 95%. These findings highlight the environmental and technological potential of the studied catalysts, reinforcing the economic viability and ecological relevance of reusing industrial waste in the sustainable production of biodiesel from waste oils.
本研究旨在探索将观赏石废料用作α-MoO₃催化剂的载体，以开发用于生物柴油生产的高效且可持续的多相体系。采用包括Rietveld精修的X射线衍射、傅里叶变换红外光谱和拉曼光谱、带能谱分析的扫描电子显微镜、透射电子显微镜、氮吸附/脱附（BET法）、粒度分布、氨程序升温脱附（TPD-NH₃）、磁性测量以及气相色谱等物理化学技术对催化剂进行表征，以分析同时进行的酯交换/酯化（TES）反应并定量甲酯和乙酯。XRD图谱揭示了诸如云母-黑云母、铁-钙铁辉石、钠长石、石英以及铁镁硅酸盐（催化载体的成分）等晶相，以及正交晶系的α-MoO₃相，在多相体系中也得到了证实。傅里叶变换红外光谱和拉曼分析显示了特征振动带，而扫描电子显微镜图像显示出不规则团聚体，透射电子显微镜也证实了这一点。氮吸附等温线表明具有介孔结构，表面积范围为0.615至3.87 m²/g。粒度分析显示D₅₀值在5.02至20.00μm之间，总酸度范围为77.0至245 μmol/g的NH₃。磁性测试表明具有亚铁磁性行为。催化性能证实了该废料作为α-MoO₃载体的有效性，特别是在含有40%钼离子的体系（40%σ-MoO₃:废料）中，其转化率达到78%至95%。这些发现突出了所研究催化剂的环境和技术潜力，增强了在从废油可持续生产生物柴油中再利用工业废料的经济可行性和生态相关性。
