## 3 Results and Discussion
### Pyrolysis of Sugarcane Bagsase  
The pyrolysis of sugarcane bagasse was performed at different reaction times (from 1 to 45 min) to determine the fraction of liquid, solid, and gas. In each reaction, 5% weight of CuO CH and 1160 Watts in a N\({}_{2}\) atmosphere were used, the results are presented in Figure 6. At 4 min of reaction time a maximum liquid (bio-oil) yield was obtained, at higher times no significant changes were found. For this reason, this time was taken as the optimal reaction time. Figure 5: Nitrogen adsorption-desorption isotherms of CuO with different treatments during the synthesis. Figure 6: Fractions obtained in the pyrolysis of cane bagasse at different reaction times using CuO as an absorbent. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & **Specific Surface Area (m\({}^{2}\)/g)** & **Pore Diameter (Å)** & **Pore Volume (cm\({}^{3}\)/g)** \\ \hline
**CuO MW** & 12 & 103 & 0.03 \\
**CuO US** & 6 & 132 & 0.02 \\
**CuO MWUS** & 6 & 97 & 0.02 \\
**CuO CH** & 9 & 103 & 0.02 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Specific area, pore diameter, and pore volume of copper oxide synthesized by different treatments. Pyrolysis of cane bagasse was performed using CuO synthesized with different treatments and a test was made without CuO. The same conditions as above of power, inert atmosphere, reaction time, and weight of CuO were used in all reactions, the results are presented in Figure 7. It can be observed that there are no significant changes in the amount of liquid fraction using CuO synthesized with different treatments. There is an average of 12% weight of bio-oil, indicating that the changes in the morphological and textural properties of the absorbent do not generate significant variations in the obtained fractions during the microwave-assisted pyrolysis. The pyrolysis with CuO has a larger bio-oil product compared with the pyrolysis without absorbent, which is 12.5 and 5.2%, respectively. This is because the bagasse is not a good microwave absorbent. It should be noted that the catalysts synthesized by ultrasound and microwave techniques are performed in only 5 min of treatment. The effect of the particle size of the cane bagasse in the pyrolysis was analyzed. The reaction was achieved using different particle sizes: ps \(<\) 0.5 mm, 0.5 mm \(<\) ps \(<\) 1.7 mm, 1.7 mm \(<\) ps \(<\) 3.5 mm. The reactions were accomplished in an inert atmosphere at 1160 Watts and 10% CuO US, the results are presented in Figure 8. The smallest particle size (ps \(<\) 0.5 mm) generates the highest liquid fraction (14.5%), unlike the results reported by [PERSON], where the size that generated the highest liquid yield was in the interval of 1-1.7 mm when using conduction heating [35]. Figure 8: Fractions obtained in the pyrolysis of cane bagasse using different particle sizes. Figure 7: Fractions obtained in the pyrolysis of cane bagasse using as absorber CuO synthesizing with microwave treatment, ultrasound, combined mode, conduction heating, and a test performed without the absorber (W CuO). A smaller particle size allows a larger contact surface between the bagasse and the microwave absorbent, promoting more homogeneous heating in the bagasse-CuO mixture. A comparison of the crystalline phases in the solid fraction was made before and after pyrolysis. Figure 9 shows the XRD patterns of cane bagasse mixed with CuO before and after the pyrolysis. The composition of the crystalline phases of the copper species present in the carbonaceous residue (after the pyrolysis) was obtained by Rietveld analysis. The XRD patterns of Figure 9 show cellulose I\(\beta\) and CuO with monoclinic crystalline systems in both cases. The identification of cellulose was performed using the work published by [PERSON] ([PERSON] 2014) and for CuO the ICDD 01-089-5899 card. Additionally, in the carbonaceous residue, Cu\({}_{2}\)O and Cu with a cubic crystalline system were also identified; the identification was made with the ICDD 01-085-1325 and 01-077-0199 cards, respectively.