Extraction of Phthalic Acid from Aqueous Solution by Using Ionic Liquids: A Quantum Chemical Approach

Abstract

Phthalic acid is an industrial chemical and it comes under the domain of endocrine disrupting chemicals (EDCs). Green solvents such as ionic liquids (ILs) posses good extractable capabilities for EDCs. COSMO–RS methodology is a widely accepted method for the design or selection of ionic liquids. COSMO–RS is a quantum chemical based method based on COSMO polarization charge densities. In this work the model has been used to screen the potential ionic liquids for the removal of phthalic acid from water. Five group of ILs with cations such as phosphonium, imidazolium, pyridinium, pyrolidinium and ammonium based were screened at infinite dilution. A total of 34 cations and 29 anions i.e. 986 possible ILs were screened and their selectivities and capacities predicted. The selectivities of the screened ILs are : phosphonium > pyrolidinium > imidazolium > ammonim > pyridinium. Some of the ionic liquids with selectivities were [TBP][CF3SO3] (16057), [OMPYR][BF4] (13265), [C4DMIM][CF3SO3] (11678), [MNH][DEC] (9650) and [C8MPY][CF3SO3] (4735). Experimental validation was done by comparing experimental logarithmic octanol–water partition coefficient values (Log Kow) with COSMO–RS predicted data on phthalic acid. The results of this study suggested that the ILs can be a possible substitute for the treatment of organic effluent rich water and wastewater