## 3 Results
### Characterization of Natural Alophane
#### 3.1.4 Fourier Transform Infrared Spectroscopy Assays (FT-IR)  
The absorption band at 1640 cm\({}^{-1}\) H\({}_{2}\)O and the infrared (IR) vibration ranges of allophane rich in aluminum bonds (SI-O-AL) are shown at 1300-800 cm\({}^{-1}\). The characteristic infrared band of allophane is 348 cm\({}^{-1}\); however, this band can only be assigned to allophane if it is absent from illite, montmorillonite, kaolinite, and halloysite. None of the different natural samples is free of the above-mentioned minerals, as the numerical values are shown in Table 4. Table 4 shows the main bands of the different samples of natural allophane identifying the vibration bands of water molecules (OH groups), deformation caused by H\({}_{2}\)O, and allophane rich in aluminum. The numerical value of natural allophane AN-7 and AN-8 is out of range; for that reason, we discarded them for the following tests.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Natural Allophane**} & **Vibration of Water Molecules. OH Groups** & **Deformation Caused by H\({}_{2}\)O** & **Allophane Rich in Aluminum** & **Infrared Band Characteristic of the Allophane Absent from Illinois. Montmorillonite. Kaolinite, and Halloysite** \\ \cline{2-5}  & & & & **Ca\({}^{-1}\)** & \\ \hline \multirow{4}{*}{AN-1} & 3452.00 & 1642.3 & 997.17 & 527.37 \\  & 3435.5 & 1639 & 990.55 & 484.36 \\  & 3442.1 & 1639 & 993.86 & 484.9 \\ \hline \multirow{4}{*}{AN-2} & 3435.5 & 1635.7 & 983.94 & 487.67 \\  & 3462 & 1639 & 990.55 & 487.61 \\  & 3455.3 & 1639 & 987.25 & 484.61 \\ \hline \multirow{4}{*}{AN-3} & 3329.6 & 1635.7 & 970.70 & 438.05 \\  & 3329.5 & 1635.7 & 983.94 & 447.97 \\  & 3435.5 & 1635.7 & 983.94 & 434.36 \\ \hline \multirow{4}{*}{AN-4} & 3326.3 & 1642.3 & 970.70 & 481.06 \\  & 3448.7 & 1635.7 & 983.94 & 467.82 \\  & 3440.7 & 1639 & 993.94 & 467.82 \\ \hline \multirow{4}{*}{AN-5} & 3458.6 & 1635.7 & 993.86 & 497.6 \\  & 3458.6 & 1635.7 & 987.25 & 504.22 \\  & 3462 & 1635.7 & 993.86 & 497.6 \\ \hline \multirow{4}{*}{AN-6} & 3450.5 & 1635.8 & 998.77 & 469.36 \\  & 3452 & 1632.4 & 997.17 & 469.7 \\  & 3452 & 1635.7 & 987.25 & 474.44 \\ \hline \multirow{4}{*}{AN-7} & & 1635.7 & 1036.9 & 471.13 \\  & & 1635.7 & 1033.6 & 474.44 \\  & & 1639 & 1040.2 & 471.13 \\ \hline \multirow{4}{*}{AN-8} & & 1635.7 & 1033.6 & 477.75 \\  & & 1645.6 & 1036.9 & 471.13 \\  & & 1639 & 1036.9 & 467.82 \\ \hline \multirow{4}{*}{AN-9} & 3545.4 & 1642.3 & 980.63 & 498.2 \\  & 3441.2 & 1635.7 & 974.01 & 504.22 \\  & 3458.6 & 1639 & 974.01 & 497.6 \\ \hline \multirow{4}{*}{AN-10} & 3458.6 & 1642.3 & 974.01 & 500.9 \\  & 3448.7 & 1639 & 980.63 & 510.83 \\  & 3447.6 & 1638.6 & 981.78 & 503.33 \\ \hline \multirow{4}{*}{AN-13} & 3448.7 & 1635.7 & 1013.7 & 494.3 \\  & 3455.3 & 1639 & 1020.3 & 487.67 \\ \cline{1-1}  & 3448.7 & 1639 & 1023.6 & 487.7 \\ \hline \multirow{4}{*}{AN-14} & 3448.7 & 1642.3 & 1017.0 & 507.52 \\  & 3455.3 & 1639 & 997.17 & 507.52 \\ \cline{1-1}  & 3452 & 1632.4 & 983.94 & 507.52 \\ \hline \multirow{4}{*}{AN-15} & 3455.3 & 1639 & 1003.8 & 500.9 \\ \cline{1-1}  & 3452 & 1639 & 1013.7 & 497.6 \\ \cline{1-1}  & 3452 & 1639 & 1020.3 & 494.3 \\ \hline \end{tabular}
\end{table}
Table 4: FT-IR infrared spectra for main bands of natural allophane.