# Effects of Different Variables on the Formation of Mesopores in Y Zeolite by the Action of CTA+
## 4 Conclusions  
The proposed methodology was effective for the creation of mesopores in USY zeolite in the presence of CTA\({}^{+}\) cations. The presence of the CTA\({}^{+}\) cations was fundamental in the modification process, since the cations hindered the attack by hydroxyl (OH\({}^{-}\)) groups, avoiding the dissolution of the zeolite crystals during the modification.  
The use of an alkaline treatment was essential, since the absence of the base resulted in the lack of mesoporous creation. Therefore, mesoporous formation in the USY zeolite required the simultaneous presence of the alkaline medium and the CTA\({}^{+}\) surfactant.  
Figure 14: Nitrogen adsorption isotherms for the zeolite samples used to evaluate the effect of the presence of CTA\({}^{+}\).  
In addition to the protective effect of the CTA\({}^{+}\) surfactant, an increase in its concentration had a positive effect on increasing the mesopore volume of the modified zeolites, without reducing the relative crystallinity, different than the behavior observed following variation of the alkaline medium concentration. A higher concentration of the alkaline medium significantly influenced the textural properties and the relative crystallinity values of the modified zeolites.  
The total quantities of acid sites of the modified zeolites were lower than for the original USY zeolite. Increasing the alkaline medium concentration used in the modification resulted in lower acidity due to the substantial decrease in the micropore volume. This reduction in the quantity of acid sites could be attributed to changes in the chemical environments of aluminum.  
The USY zeolite with Si/Al = 15 was highly sensitive to desilication, preventing the formation of a substantial volume of mesopores without amorphization or even total destruction of the zeolite structure. Therefore, the methodology described here is attractive, as it is a versatile technique that increases the mesopore volume, without risking loss of the zeolitic structure.  
The following are available online at [[http://www.mdpi.com/2076-3417/8/8/1299/s1](http://www.mdpi.com/2076-3417/8/8/1299/s1)]([http://www.mdpi.com/2076-3417/8/8/1299/s1](http://www.mdpi.com/2076-3417/8/8/1299/s1)), Figure S1: X-ray diffractograms of the sample YB0.08-S0, Figure S2: Nitrogen adsorption (closed symbols) and desorption (open desorption) isotherms at 77 K of the modified samples produced using different concentrations surfactant, Figure S3: Nitrogen adsorption (closed symbols) and desorption (open desorption) isotherms at 77 K of the modified samples produced using different concentrations of the alkaline medium, Figure S4: Thermogravimetric analysis of the sample original USY and YB0.04-CTA+60/6h.  
[PERSON] and [PERSON] designed the experiments; [PERSON] and [PERSON] performed the experimental work; [PERSON], [PERSON], and [PERSON] analyzed the data; [PERSON] provided reagents, materials, and analysis tools; [PERSON] wrote the article, with contributions from [PERSON] and [PERSON].  
This research received no external funding.  
The authors are grateful to CAPES/MEC for scholarship support.  
The authors declare no conflicts of interest.