## 3 Results
### Samples Characterization
This preparation of boehmite showed nanosheets assembled with nanoparticles in the absence of surfactants at a lower reaction temperature, such as 60 \({}^{\circ}\)C. Other authors have found nanosheets when they prepared boehmite samples at a pH near 7 [38]. The porosity properties produced by the obtained boehmite nanosheets demonstrated that the material can be utilized as adsorbent to separate the paraffin mixture. Figure 3: IR spectra of boehmite (**a**) and \(\gamma\)–Al\({}_{2}\)O\({}_{3}\) calcined at 550 \({}^{\circ}\)C (**b**). Figure 2: TG (Blue line) and DTG (Red line) of boehmite. The N\({}_{2}\) adsorption isotherm at \(-196\)\({}^{\circ}\)C was, according to the IUPAC classification, of type III, typical of microporous solids, and showed a nearly linear dependence between the adsorbed amount of N\({}_{2}\)and the equilibrium pressure up to approximately 475 mmHg. After this pressure, it was clearly distinguished a gradual slope and a final sharp rise that is characteristic of capillary condensation (Figure 5A). The specific surface area (Se) of 10.7 m\({}^{2}\)/g, obtained by the BET method, showed that during the process of synthesis the clumping of small pseudo-boehmite particles should occur. This could be explained due to the great speed of hydrolysis of aluminum precursor that can originate different morphologies and sizes of the synthesized material [39], thereby promoting bonding of particles to reduce the surface energy of the system. Additionally, it is known that the diffusion of N\({}_{2}\) molecules at \(-196\)\({}^{\circ}\)C in the micropores of a material is difficult and therefore discarding at that temperature the diffusion through the narrow spaces between the layers of boehmite particles linked by -OH groups. This was confirmed when the curve of dependency of the amount of adsorbed N\({}_{2}\) as a function of time was analyzed (Figure 5B) and compared to that of dealuminated clinoptiolite [19]. In the latter case, N\({}_{2}\) was disseminated inside the solid and the adsorption process lasted more than three hours, whereas boehmite N\({}_{2}\) adsorption hardly lasted three minutes. Moreover, on the same curve it was observed that the adsorption process occurred in three stages: the first to 47 mmHg (A-B), the second between 59 and 519 mmHg (C-D) and third corresponding to abrupt capillary condensation, from the equilibrium pressure of 537 mmHg (E-F). The isotherm range before the capillary condensation made by the two terms of Dubinin method showed the existence of two zones in the mesoporous system. The Dubinin-Stoeckli criterion [27] was applied to determine the average pore diameter (Dp = /Ec) and a narrow pore region centred at Dp = 5.2 nm was found as well as another region with mean pore widths of Dp = 19.2 nm, being the last pore diameters large enough to allow diffusion of big molecules (Table 1). Figure 4: SEM micrographs of the as-prepared boehmite  
It is believed that the fast N\({}_{2}\) adsorption at \(-\)196 \({}^{\circ}\)C occurs on the mesoporous surface formed during synthesis and it is observed a satisfactory correspondence between the fitted isotherm and the experimental isotherm as well as the kinetics (Figure 6A,B). In both isotherms, it was shown that the adsorption during the first stage of adsorption essentially corresponded to the first area of Dubinin mesopores and the adsorption during the second stage occurred in the second zone of Dubinin mesopores, respectively. \begin{table}
\begin{tabular}{c c c c} \hline
**Zone** & **N\({}_{\text{m}}\) [mmol/g]** & **E\({}_{\text{c}}\) [J/mol]** & **D\({}_{\text{p}}\) [nm].** \\ \hline
1 & 0.041 & 2481 & 5.2 \\
2 & 0.056 & 669 & 19.4 \\ \hline \end{tabular}  
* Nm: Maximum adsorption Dubinin areas. Ec: characteristic energies. Dp: and average pore diameter.  
\end{table} 
Table 1: Parameter settings of two terms Dubinin equation obtained from nitrogen adsorption isotherm.