Abstract
Despite the existence of numerous conventional wastewater treatment techniques, an efficient method for removing micropollutants, dyes, and heavy metal ions from wastewater remains elusive. The need to develop sustainable alternatives to eliminate these toxins from the various effluent has become a pressing issue [1]. Recently, ionic liquids (ILs) have emerged as a promising possibility for task-specific and efficient pollutant extraction media because of the ease in structural tunability and other unique chemical properties [2]. Deep eutectic solvents (DES), often referred to as a subclass of ILs, were also renowned for their wastewater treatment capability [3]. IL and DES-based liquid-liquid extraction (LLE) methods are widely popular in recent times because of the ease of execution and specificity. In this context, the overall aim was to develop novel ILs and DES to remove hazardous pollutants from wastewater samples. In our research, alkanolamine-based ILs with varying alkyl chain lengths were developed to effectively eliminate pharmaceutical pollutants from wastewater [4]. Furthermore, the effectiveness of pseudoprotic ionic liquids derived from trioctylamine and octanoic acid in removing cationic, anionic, and neutral dyes from textile wastewater was explored. Effective elimination of toxic heavy metal ions like Pb2+, Ni2+, Cd2+, and Cu2+ from simulated wastewater samples was achieved through the use of ILs with varying carboxylate anions. The removal of personal care product residues from model wastewater samples was successfully attained using DESs based on terpenes and long-chain carboxylic acid. For all these studies, LLE method was employed and the parameters affecting extraction efficiency (EE) were optimized. Computational studies based on density functional theory (DFT) and Conductor like Screening MOdel for Real Solvents (COSMO-RS) were used for the interpretation of the extraction mechanism. The reusability of ILs and DESs were also explored. Hydrophobicity, hydrogen bonding, and π−π interactions were found to be the major driving forces behind the extraction processes.
References

[1] Bhatt, P., Bhandari, G., & Bilal, M. (2022) J. Environ. Chem. Eng., 10(3), 107598.
[2] Padinhattath, S. P., Chenthamara, B., & Gardas, R. L. (2021) Acta Indian Rummy Games., 38, 62-79.
[3] Smith, E L., Abbott, A P., & Ryder K S. (2014) Chem. Rev., 114, 11060–11082.
[4] Padinhattath, S. P., & Gardas, R. L. (2023) J. Mol. Liq., 378, 121603.