## 4 Conclusions  
Four commercial ACs were successfully tested for the removal of 4-EP and 4-EG from the aqueous phase and ethanol-containing wine-like solutions. To improve the AC capacity for the removal of 4-EP and 4-EG, AC from Merck has been chemically modified through its impregnation into NaOH and HNO\({}_{3}\) solutions. The textural properties of the modified ACs presented only minor changes, however, the chemical surface changed significantly, as illustrated in the FTIR spectrum and through the change of pHpzc.  
In the systems studied, when only one or both compounds were present in the same solution, 4-EG was adsorbed to a greater extent, but 4-EP was retained to a greater extent. Ethanol had a competing effect on the adsorption of 4-EG and 4-EP when only one compound was present in the solution. Thus, when both compounds were present in the same solution, the presence of ethanol appeared to promote a cooperative effect and favour the adsorption of both compounds. These results are very promising as the use of modified ACs with a basic character show a better performance in the removal of 4-EG and 4-EP in the presence of ethanol. ACs with similar properties may be a solution for the removal of these unpleasant compounds from red wine, up to a level below the perception threshold. However, it is necessary to deepen the knowledge of the removal efficiency of 4-EP and 4-EG and their effects on red wine quality.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app122211754/s1](https://www.mdpi.com/article/10.3390/app122211754/s1)]([https://www.mdpi.com/article/10.3390/app122211754/s1](https://www.mdpi.com/article/10.3390/app122211754/s1)), Figure S1: Nitrogen adsorption isotherms obtained, at 77 K, on the commercial AC, from Merck, submitted to basic treatments with NaOH; Figure S2: Nitrogen adsorption obtained, at 77 K, on the commercial AC, from Merck, submitted to treatments with HNO\({}_{3}\); Figure S3: FTIR spectra of AC from Merck, as received and after submitted to acid treatments with HNO\({}_{3}\); Figure S4: FTIR spectra of AC from Merck, as received and after submitted to basic treatments with NaOH; Figure S5: Adsorption isotherms of 4-EP and 4-EG obtained from solutions where the phenolic compounds were isolated or present in a mixture, (a) Panreac; (b) Merck; (c) Merck-HNO3-10.  
Conceptualization, I.P.d.P.C. and P.A.M.M.; methodology, I.P.d.P.C. and P.A.M.M.; software, P.A.M.M.; validation, I.P.d.P.C. and P.A.M.M.; formal analysis, I.P.d.P.C. and P.A.M.M.; investigation, I.D.M., V.P. and J.J.; resources, P.A.M.M.; data curation, I.D.M., V.P. and J.J.; writing--original draft preparation, I.D.M., V.P. and J.J.; writing--review and editing, I.P.d.P.C. and P.A.M.M.; visualization, I.P.d.P.C.; supervision, I.P.d.P.C. and P.A.M.M.; project administration, I.P.d.P.C.; funding acquisition, P.A.M.M. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was funded by FCT (Project UID/QUI/0619/2016) with National (OE) funds.  
**Informed Consent Statement:** Not applicable.  
**Conflicts of Interest:** The authors declare no conflict of interest.