Removal of methylene blue by new tunable aryl/alkyl ionic liquids/salts (TAAILs) from aqueous solution

The removal of methylene blue (MB) from aqueous solution has been investigated using new tunable 1-aryl-2-alkyl-3,5-dimethylpyrazolium hexafluorophosphate salts ([Ph_RC_Rˈpz][PF₆], R: -Cl, -Br, -Me, -OMe, Rˈ: -C₂H₅, or -C₄H₉) as an extractant and methylene chloride as a diluent. The influence of p-substituent and alkyl chain length on the removal efficiency of MB from aqueous solution was investigated. The obtained results show that MB was extracted from aqueous solution with high extraction efficiency up to 99.7 % in a very short time. The salt (4a) used for extraction of MB was recovered and reused for four runs.