## 4 Conclusions  
The main objective of this work was the study of the capability of ILs, based on different anions and cations, to remove and recover phenolic compounds from water. Taking into account the experimental results, it is possible to conclude that the extraction efficiency was not affected significantly for the aromaticity of the cation ring, obtaining similar efficiencies for pyridinium and pyrrolidinium cations, with extraction yields above 90%. Furthermore, there were no significant differences between the results obtained with [NTf\({}_{2}\)] and [Nf\({}_{2}\)] anions. Besides, the capability to remove a mixture of phenols from water was studied, obtaining also high extraction efficiencies, above 80%. All the studied ionic liquids present high and similar results, except in the case of low initial phenolic compounds concentration, where [1P1 Mpyr][Nf\({}_{2}\)] presents the worst results. After this study, it is possible to conclude that a method of elimination and recovery phenolic pollutant from wastewater was achieved. The [1P1 Mpyr][NTf\({}_{2}\)] ionic liquid is a good candidate as an elimination agent of phenolic compounds, obtaining treated wastewater, complying the legal limits for their discharge or reuse, and attaining the recovery of both extraction solvents and phenolic compounds. The following are available online at [[http://www.mdpi.com/2076-3417/9/20/4321/s1](http://www.mdpi.com/2076-3417/9/20/4321/s1)]([http://www.mdpi.com/2076-3417/9/20/4321/s1](http://www.mdpi.com/2076-3417/9/20/4321/s1)), Table S1: Cation and anion structure of the studied ionic liquids and their corresponding names, Table S2: Initial concentration C\({}_{\text{i}}\) (mg\(\cdot\)L\({}^{-1}\)) vs. final concentration C\({}_{\text{f}}\) (mg\(\cdot\)L\({}^{-1}\)) of phenol o-cesol and 2-chlorophenol after extraction process using [1P1 Mpip][NTf\({}_{2}\)], [1P3 Mpyr][NTf\({}_{2}\)], [1P1 Mpyr][NTf\({}_{2}\)] and [1P1 Mpyr][Nf\({}_{2}\)] at T = 298.15 K and P = 101.3 kPa, Table S3: Initial concentration C\({}_{\text{i}}\) (mg\(\cdot\)L\({}^{-1}\)) vs. extraction efficiency (E%) of phenol o-cesol and 2-chlorophenol after extraction process using [1P1 Mpip][NTf\({}_{2}\)], [1P3 Mpyr][NTf\({}_{2}\)], [1P1 Mpyr][NTf\({}_{2}\)], [1P1 Mpyr][NTf\({}_{2}\)], and [1P1 Mpyr][Nf\({}_{2}\)] at T = 298.15 K and P = 101.3 kPa, Table S4: Initial concentration C\({}_{\text{i}}\) (mg\(\cdot\)L\({}^{-1}\)) vs. extraction efficiency (E%) of a mixture of phenolic compounds (PCM) after extraction process using [1P1 Mpip][NTf\({}_{2}\)], [1P3 Mpyr][NTf\({}_{2}\)], [1P1 Mpyr][NTf\({}_{2}\)], and [1P1 Mpyr][Nf\({}_{2}\)] at T = 298.15 K and P = 101.3 kPa, Table S5: Initial concentration C\({}_{\text{i}}\) (mg\(\cdot\)L\({}^{-1}\)) vs. final concentration C\({}_{\text{f}}\) (mg\(\cdot\)L\({}^{-1}\)) of a mixture of phenolic compounds (PCM) after extraction process using [1P1 Mpip][NTf\({}_{2}\)], [1P1 Mpiper][NTf\({}_{2}\)], [1P1 Mpyr][NTf\({}_{2}\)], [1P1 Mpyr][NTf\({}_{2}\)], and [1P1 Mpyr][Nf\({}_{2}\)] at T = 298.15 K and P = 101.3 kPa. Figure S1. Extraction efficiencies (E%) of 2-chlorophenol using [PMim][NTf\({}_{2}\)], [BMim][NTf\({}_{2}\)], [HMim][NTf\({}_{2}\)], [C2 mim][FSI, [PMpip][NTf\({}_{2}\)], [PMpy][NTf\({}_{2}\)], [PMpy][NTf\({}_{2}\)], and [PMpyr][Nf\({}_{2}\)]. Initial concentrations (--) 5 mg\(\cdot\)L-1 and (--) 50 mg\(\cdot\)L-1. Figure S2. 1H NMR spectrum for the pure IL 1-methyl-1-propylpyrrolidininium bis(trifluoromethylsulfonyl)imide. Figure S3. 1H NMR spectrum for the IL 1-methyl-1-propylpyrrolidininium bis(trifluoromethylsulfonyl)imide after the recovery process using 0.5 M NaOH. Investigation, O.G.S. ; Methodology, B.G. and A.D.; Supervision, B.G. and A.D.; Writing--original draft, O.G.S. ; Writing--review & editing, B.G. and A.D. This research was funded by Comision Interministerial de Ciencia y Tecnologia (Spain), grant number CTM2013-46093-P.  
[PERSON] is grateful to the Comision Interministerial de Ciencia y Tecnologia (Spain) for her FPI grant (BES-2014-067694).