# Novel ZIF-67@Bentonite (ZIF-67@BNT) Nanocomposite for Aqueous Methyl Orange Removal
## 3 Results and Discussion
### ZIF-67@BNT Characterization
#### 3.1.2 Fourier Transform Infrared Spectroscopy Analysis  
Besides the crystallinity, Fourier transform infrared spectroscopy (FTIR) results of BNT, ZIF-67, and the ZIF-67@BNT composite are shown in Figure 5B, providing insight into the functional groups and interactions present between the components. BNT displays a wide O-H stretching band at 3100 cm\({}^{-1}\) due to adsorbed water, as well as peaks at 2370 cm\({}^{-1}\) (C-H stretching), 1408 cm\({}^{-1}\) (C=N stretching), 1170 cm\({}^{-1}\) (C=C stretching), and 970 cm\({}^{-1}\) (Si-OH bending), which are a consequence of its layered silicate structure. These peaks indicate the presence of montmorillonite and silicate groups, responsible for the BNT's adsorption capacity [47; 48].  
The FTIR spectrum of ZIF-67 exhibits some characteristic vibrational modes related to its MOF structure. The Co-N stretching vibration coincides with a clear peak at 538 cm\({}^{-1}\), therefore verifying the coordination between cobalt ions and the 2-methylimidazole linker. Strong O-H stretching vibrations imply the hydrophobic character of ZIF-67, which is anticipated from the non-polar imidazolate linkers. Since C=N and C=C stretching modes compose the fundamental structure of the MOF, their presence promotes the stability of the ZIF-67 framework even more. Crucially for preserving adsorption efficiency, the well-defined peaks of ZIF-67 point to a highly crystalline and stable framework [49].  
Figure 5: The ZIF-67@BNT nanocomposite’s crystalline structure and functional group characterization are shown in **(A)** XRD patterns and **(B)** FTIR spectra, respectively.  
In the ZIF-67@BNT, significant spectrum alterations noticed in the ZIF-67@BNT composite indicate robust interactions between ZIF-67 and BNT. N-H stretching at 3232 cm\({}^{-1}\) points to interactions between the hydroxyl (-OH) groups of BNTs and the imidazolate linkers of ZIF-67. New C-H stretching vibrations at 2738 cm\({}^{-1}\) (aromatic) and 2600 cm\({}^{-1}\) (aliphatic) point to changes in the organic framework of the MOF, maybe resulting from surface alterations following integration with BNT or electrostatic interactions. Retention of the Co-N peak at 538 cm\({}^{-1}\) guarantees composite structural integrity of ZIF-67 [41,50].  
Due to the high interfacial interactions between the two adsorbent materials, ZIF-67@BNT exhibits additional distinctive peaks when compared to ZIF-67 and BNT. Electrostatic interactions between the Co\({}^{2+}\) metal centers in the ZIF-67 framework and the negatively charged BNT surface cause structural modifications, while hydrogen bonding between the hydroxyl groups of BNT and the imidazolate linkers of ZIF-67 causes changes in vibrational frequencies. Spectral fluctuations may also be caused by the emergence of new functional groups or changes to the electrical environment of existing groups brought about by ZIF-67's integration into the BNT matrix. Alterations to the peak intensities and movement of the peaks point to altered adsorption sites, which may improve the composite's efficacy in pollutant removal [51, 52, 53].