**3. Conclusions**

 This study concludes that the catalytic activity for MTBE oxidation of catalysts Ru, Au, and Ag, supported on Al2O3, CeO2, and Al2O3-CeO2, synthesized by wet impregnation methods and DP with NaOH and urea, in two steps, is classified as follows:

$$\text{AuAlCe}\_5\text{DPU} > \text{RuAlCe}\_1\text{IH} > \text{AgCeDPNa} \tag{5}$$

In addition, the catalytic activity for the oxidation of target molecule ETBE on Cu catalysts supported on Al2O3, synthesized by three different methods in a single step, is classified as follows:

$$\text{Cu}\_{10}\text{AlSG} > \text{Cu}\_{10}\text{AlIH} > \text{Cu}\_{15}\text{AlIHU} \tag{6}$$

The catalytic activity for TAME oxidation using Copper catalysts supported on Al2O3, synthesized by three different methods in a single step and Au supported on *Nonconventional Wastewater Treatment for the Degradation of Fuel Oxygenated… DOI: http://dx.doi.org/10.5772/intechopen.84250* 

Al2O3, CeO2 and Al2O3-CeO2 synthesized by DP with urea in two steps, is classified as follows:

```
AuCeDPU > Cu15AlSG > AuAlCe3DPU > Cu10AlIHU = Cu15AlIH (7)
```