## 3 Results
### Catalyst Characterization
Beyond 500 \({}^{\circ}\)C, the weight loss rate decreases significantly, showing a more stable profile up to 1000 \({}^{\circ}\)C. Notably, the overall weight loss in LiSA across the full temperature range is less than that of SAS, suggesting that lithium impregnation enhances the thermal stability of the support. The specific surface area (S\({}_{\text{BET}}\)) and average pore diameter (D) values obtained from nitrogen adsorption-desorption isotherms are summarized in Table 1. A decrease in the S\({}_{\text{BET}}\) was observed after lithium impregnation of the support material. This reduction suggests that the support's surface becomes coated, and micropores are filled during the impregnation process. This behavior aligns with previous reports on supported materials impregnated with active metals [15]. Figure 4: XRD patterns (**a**) and TGA curves (**b**) of structured aluminosilicate materials. Furthermore, the results reveal changes in the average pore diameter, indicating partial pore blockage due to lithium incorporation into the support matrix. This phenomenon, leading to a decrease in specific surface area, is consistent with trends reported in the literature for impregnated materials [16, 17]. Additionally, the D values confirm that the materials exhibit a mesoporous or macroporous structure (pore diameter > 2 nm), as further corroborated by scanning electron microscopy (SEM) images (Figure 3). This structure is crucial for reducing diffusion limitations when interacting with bulky molecules like triglycerides, which are estimated to have diameters of 2-4 nm based on molecular modeling [18]. The lithium content analysis by ICP-MS (Table 1) revealed that the initially structured aluminosilicate (SAS) material contained no detectable lithium, while the impregnated material (LiSA) showed a concentration of 15.2 mg Li/g, which corresponds to 1.52% by weight of lithium. Although theoretical calculations prior to impregnation indicated an expected lithium loading of 5% by weight, the final obtained value is lower. This deviation aligns with findings reported in the literature and can be attributed to several factors inherent to the impregnation process. Firstly, impregnation efficiency is rarely 100%, as some of the precursors may not fully interact with the support during the process. Additionally, losses during drying and calcination can occur. The drying stage is particularly critical, as it can lead to redistribution of the impregnated lithium within the support, potentially resulting in non-uniform distribution. Moreover, the structural properties of the support, such as its porosity and density, play a significant role. Denser regions at the edges of the support may retain different amounts of lithium compared to less dense areas, leading to localized variations in concentration [19]. Finally, the interaction between the lithium precursor and the aluminosilicate support influences the final lithium loading. If the interaction is weak, lithium may aggregate into larger, unsupported particles, reducing its homogeneous incorporation into the matrix [20]. Despite these variations, the lithium incorporation was confirmed by XRD patterns, supporting the successful impregnation of lithium.