## 3 Results
### Characterization of CALB@MCM-41-C\({}_{8}\)  
The surface morphology and internal structures of MCM-41 were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM results in Figure 2a show that MCM-41 molecular sieves are irregular and non-uniform spherical clusters, which is consistent with previous reports [51]. The TEM results in Figure 2b clearly indicate that MCM-41 were densely and orderly distributed hexagonal mesopores, presenting uniformly layered structures and fingerprint-like patterns. The nitrogen adsorption and desorption isotherms (Figure 2c) indicate that both MCM-41 and MCM-41-C\({}_{8}\) showed type IV isotherms and H1 hysteresis loops with the properties of mesoporous materials [52]. The detailed text parameters obtained using BET analysis for MCM-41, MCM-41-C\({}_{8}\), and CALB@MCM-41-C\({}_{8}\) are presented in Table 1. It is evident that compared to MCM-41, the specific surface area of MCM-41-C\({}_{8}\) decreased sharply from 1439.9 m\({}^{2}\)/g to 449 m\({}^{2}\)/g, indicating the effective grafting of C8 onto MCM-41. Additionally, the water contact angle of the MCM-41 was increased from 55\({}^{\circ}\) to 107\({}^{\circ}\) after surface modification (Figure S2), suggesting a shift towards a more hydrophobic carrier [53]. Similarly, the specific surface area of CALB@MCM-41-C\({}_{8}\) was further decreased to 130.2 m\({}^{2}\)/g, along with the simultaneous reduction in pore volume from 1.0 cm\({}^{3}\)/g to 0.1 cm\({}^{3}\)/g. Hence, it is confirmed that lipase CALB has been successfully immobilized on the hydrophobic carrier of MCM-41-C\({}_{8}\).  
Furthermore, FT-IR spectroscopy was used to analyze the functional groups of the carrier and immobilized lipases. As depicted in Figure 2e, the characteristic peaks at 2929 cm\({}^{-1}\) and 2854 cm\({}^{-1}\) corresponded to the symmetric and asymmetric tensile vibrations of -C-H, respectively, suggesting the grafting of C\({}_{8}\) onto MCM-41. Moreover, the characteristic peak at 1541 cm\({}^{-1}\) in the spectrum of CALB@MCM-41-C\({}_{8}\) refers to the -N vibration, thus confirming the immobilization of lipase CALB. Moreover, XPS further demonstrates the elemental peaks of C1s, Si2p, O1s, and N1s with a corresponding binding energy of 285.1 eV, 102.1 eV, 532.1 eV, and 399.1 eV, respectively (Figure 2f). Alternatively, compared to MCM-41, whose C 1s content was 16.3%, MCM-41-C\({}_{8}\) and CALB@MCM-41-C\({}_{8}\) showed a significant increase in C 1s content to 32.2% and 37.3%, respectively, as C8 modification increased the presence of carbon groups on carriers. Similarly, the N element yielded an increase from 1.1-1.3% to 4.1% due to the presence of amino groups in the immobilized lipases [54].  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{3}{c}{**Text Properties**} & \multicolumn{3}{c}{**Elemental Content (Atomic\%)**} \\ \cline{2-7}  & **Surface Area (m\({}^{2}\)/g)** & **Pore Size (nm)** & **Pore Volume (cm\({}^{3}\)/g)** & **C1s** & **N1s** & **O1s** & **Si2p** \\ \hline MCM-41 & 1439.9 & 3.4 & 1.0 & 16.3 & 1.3 & 57.8 & 24.6 \\ MCM-41-C\({}_{8}\) & 449.0 & 4.1 & 0.5 & 32.3 & 1.1 & 45.3 & 21.4 \\ CALB@MCM-41-C\({}_{8}\) & 130.2 & 3.7 & 0.1 & 37.3 & 4.1 & 46.8 & 11.8 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Text parameters and elemental contents of sample characterization.