## 2 Materials and Methods
### Catalytic Pyrolysis
#### 3.3.2 Characterization of Liquid Fraction  
Tables 2 and 3 shows the most common compounds in the recovered biooil after the pyrolysis experiment for surgical and FFP2 masks, respectively. As other authors detailed [23; 30; 46; 47], the major compound recovered was 2,4-Dimethyl-1-heptene during the thermal pyrolysis of masks (>10%). Furthermore, cembrane, 3-Eicosene, (E)-, 5-Eicosene, (E)-, and 1,2-Epoxyhexadecane appeared in a concentration greater than 3% in thermal pyrolysis biosids from face masks. The use of sepiolite as a catalyst altered the composition of the pyrolysis liquids, significantly increasing the amount of 2,4-Dimethyl-1-heptene and other olefins, such as as 3-Eicosene, (E)- and 5-Eicosene, (E)- at the expense of naphthenes, such as cembrane. Nevertheless, the successive use of the catalyst had the opposite effect on the results obtained, reducing the quantity of light olefins as 2,4-Dimethyl-1-heptene and increasing the proportion of naphthenes, such as 1,2-Epoxyhexadecane. This behavior could be explained due to the degradation experienced by the catalyst, which reduced its micropore area and the total pore volume. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Component**} & \multicolumn{4}{c}{**Type of Pyrolysis**} \\ \cline{2-7}  & \multicolumn{2}{c}{**Thermal**} & \multicolumn{2}{c}{**Catalytic-1 st Run**} & \multicolumn{2}{c}{**Catalytic-2 nd Run**} & \multicolumn{2}{c}{**Catalytic-3 rd Run**} \\ \cline{2-7}  & \multicolumn{2}{c}{**Component**} & **Area,\%** & **Component** & **Area,\%** & **Component** & **Area,\%** & **Component** & **Area,\%** \\ \hline
1 st & 2,4-Dimethyl-1-heptene & 12.27 & 2,4-Dimethyl-1-heptene & 40.56 & 2,4-Dimethyl-1-heptene & 26.16 & 2,4-Dimethyl-1-heptene & 11.12 \\ \hline
2 nd & Cembrane & 5.59 & 3-Eicosene, (E)- & 10.97 & 3-Eicosene, (E)- & 7.13 & 12- & 12- & \\ \hline
3 rd & 3-Eicosene, (E)- & 4.48 & 5-Eicosene, (E)- & 6.22 & 1,2- & 5.46 & 3-Eicosene, (E)- & 5.73 \\ \hline
4 th & Epoxyhexadecane & 4.11 & 3-Tetradecene, (E)- & 4.01 & 1,7-Dicyclopent-4-n-octylheptane & 5.15 & 1,7-Dicyclopent-4-n-octylheptane & 4.06 \\ \hline
5 th & 1,7-Dicyclopent-1-n-octylheptane & 3.46 & 1,3,5- & 3.60 & Cembrane & 4.66 & Hexadecyl & 3.67 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Liquid components list in biooil from the pyrolysis of surgical masks. Figure 6: Comparative pyrolysis yields of surgical masks (**left**) and FFP2 masks (**right**). Moreover, the components of the biooil obtained have been grouped by the most usual functional groups. Table 4 shows the distribution by functional groups of the biooils. No aromatic compounds have been detected in the biooil from thermal pyrolysis, which coincides with other researchers [30]. However, aromatic compounds have not been found in the biooil obtained in sepiolite-catalyzed pyrolysis, in contrast to other researchers in zeolite-catalyzed pyrolysis [30,47]. In addition, it was observed that through catalytic pyrolysis, the number of olefins and isoparaffins obtained increased to the detriment of naphthenes and paraffins. However, with successive use of the catalyst, it is seen that this trend is reversed due to the degradation that occurs during use. Table 4 also shows that, for all samples, the olefin content was higher than other components, with values around 41-72%, while aromatic compounds were not found. On the other hand, biooil compounds were grouped by chain size, and the average MW of the biooil was calculated using Equation (4) (Table 5). It can be noticed that in catalytic pyrolysis (first run) compared to thermal pyrolysis, the biooil obtained has a lower chain size and lower average molecular weight. In contrast, the successive use of the catalyst has the opposite effect, increasing the chain size and the average molecular weight of the biooil, even reaching higher values than in thermal pyrolysis.