ABSTRACT
While several group contribution method (GCM) models have been developed in recent years for the prediction of ionic liquid (IL) properties, some challenges exist in their effective application. Firstly, the models have been developed and tested based on different datasets; therefore, direct comparison based on reported statistical measures is not reliable. Secondly, many of the existing models are limited in the range of ILs for which they can be used due to the lack of functional group parameters. In this paper, we examine two of the most diverse GCMs for the estimation of IL melting point; a key property in the selection and design of ILs for materials and energy applications. A comprehensive database consisting of over 1300 data points for 933 unique ILs, has been compiled and used to critically evaluate the two GCMs. One of the GCMs has been refined by introducing new functional groups and reparametrized to give improved performance for melting point estimation over a wider range of ILs. This work will aid in the targeted design of ILs for materials and energy applications.
ABSTRACT
Water pollution is a severe and challenging issue threatening the sustainable development of human civilization. Besides other pollutants, waste fluid streams contain phenolic compounds. These have an adverse effect on the human health and marine ecosystem due to their toxic, mutagenic, and carcinogenic nature. Therefore, it is necessary to remove such phenolic pollutants from waste stream fluids prior to discharging to the environment. Different methods have been proposed to remove phenolic compounds from wastewater, including extraction using ionic liquids (ILs) and deep eutectic solvent (DES), a class of organic salts having melting point below 100 °C and tunable physicochemical properties. The purpose of this review is to present the progress in utilizing ILs and DES for phenolic compound extraction from waste fluid streams. The effects of IL structural characteristics, such as anion type, cation type, alkyl chain length, and functional groups will be discussed. In addition, the impact of key process parameters such as pH, phenol concentration, phase ratio, and temperature will be also described. More importantly, several ideas for addressing the limitations of the treatment process and improving its efficiency and industrial viability will be presented. These ideas may form the basis for future studies on developing more effective IL-based processes for treating wastewaters contaminated with phenolic pollutants, to address a growing worldwide environmental problem.