## 3 Results and Discussion
### Catalysts Characterization  
In order to evaluate the quality of TiO\({}_{2}\) impregnation, it is important to make a visual evaluation of Leca particles after impregnation. The external morphology and surface characteristics can be observed in Figure 5, showing pictures of the Leca surface after coating with different TiO\({}_{2}\) loads (1% \(w/w\), 3.6% \(w/w\), 5% \(w/w\), and 10% \(w/w\)). It is observed that for the 1% \(w/w\) impregnation load (Figure 5a), the coated surface is partially devoid of TiO\({}_{2}\). Figure 5b-d illustrates the significant degree of TiO\({}_{2}\) Leca surface covering, with the intensity of the shade proportional to the percentage of TiO\({}_{2}\) in the prepared suspensions. The increase in the TiO\({}_{2}\) load means more availability of active sites to produce the reactive species during photocatalytic oxidation with suitable radiation. Figure 4: Degradation of SMX for the three photocatalysts using UVA radiation. Moreover, after coating Leca with TiO\({}_{2}\) (independent of the load), particles maintain float characteristics in the aqueous matrix. Using the Zeiss Stemi 2000-C magnifier, Figure 6 depicts the effects of solvent (water and ethanol) on the photocatalysts synthesized at 3.6%. The poor adhesion of the coating layer can be seen in the section highlighted in Figure 6a. This fact may be associated with reducing the repulsive potential (decrease in the zeta potential) that ethanol promotes between particles in suspensions that allow for maintaining adequate stability of the suspension to the coating process [38]. Figure 6b shows a more homogeneous TiO\({}_{2}\) surface when ethanol is used as a solvent in the preparation. The SEM images for 3.6%TiO\({}_{2}\)/Leca illustrated in Figure 7 shows the photocatalysts' morphology and structure. In particular, Figure 7a highlights the surrounding cross-section of the photocatalyst, which indicates that the TiO\({}_{2}\) may penetrate deep into the Leca support. Figure 7b shows that the Leca particle's core structure presents high porosity with varied dimensions of pores. After the impregnation, the internal porosity of the support remained high. Similar results of TiO\({}_{2}\) immobilization on ceramic supports have been reported by [PERSON] et al. [43]. Figure 7c shows that the photocatalyst surface shows small cracks, which may be associated with tensile stress due to capillary forces resulting from solvent evaporation and densification of the TiO\({}_{2}\) film during drying. Despite the lack of references in the literature regarding the effect of drying of alcoholic suspensions of TiO\({}_{2}\) on ceramic substrates, the occurrence of cracks with dimensions of 1.2 \(\upmu\)m on the surface of the TiO  
Figure 5: Morphology of photocatalysts prepared with (**a**) 1%; (**b**) 3.6%; (**c**) 5% and (**d**) 10%. Figure 6: Images obtained through a Zeiss Stemi 200-C magnifier showing the solvent effect on impregnation: (**a**) water; (**b**) ethanol. coated glass was reported by [44; 45]. Figure 7d depicts that the TiO\({}_{2}\) coated film is not uniform, with the thickness layer changing along the surface of the support. Figure 8 shows the results from the analysis using EDX of the Leca surface for the impregnation of TiO\({}_{2}\) with a 3.6% \(w/w\) load. We compared the elemental composition of the surface particles before and after impregnation with TiO\({}_{2}\). Silicon, aluminum, and oxygen are the most abundant elements in the core of the Leca particles, and these elements are combined in the form of oxides [23]. However, at the surface of the catalyst impregnated with the TiO\({}_{2}\), the presence of titanium was evident in great amounts since the peak intensity was high. Figure 7: (**a**) Cross-section of the photocatalyst, 3.6%-TiO\({}_{2}\)/Leca; (**b**) image of the central area of a Leca particle; (**c,d**) TiO\({}_{2}\) layer on the Leca surface.