Ionic Liquids as Extractants for Nanoplastics

Abstract

Plastic waste in the ocean and on land in the form of nanoplastics is endangering food and drinking water supplies, raising the need for new strategies for the removal of plastic nanoparticles from complex media. In the present contribution we suggest considering ionic liquids as extractants, since they show several advantageous properties that may facilitate the design of efficient separation processes. Through varying the anion and the side chain at the cation, the interactions between the extractant and the polymer can be strengthened and tuned, and thereby the disintegration of the particle into separate polymer chains can be controlled. Oxidized moieties can also be efficiently solvated, given the amphiphilic nature of the considered ionic liquids, allowing also realistic particles to be extracted into these solvents. The phase transfer was found to be thermodynamically and kinetically possible, which is supported by the complicated structure of the ionic liquid-water interface through the rearrangement of the interfacial ions, and the formation of a micelle around the plastic already at the edge of the aqueous phase.

To Waste or Not to Waste: Questioning Potential Health Risks of Micro- and Nanoplastics with a Focus on Their Ingestion and Potential Carcinogenicity

“…Upon contact with NPs, the propensity of a model protein to form α-helical and β-loop secondary structures was shifted, with the changes being qualitatively different for PE and nylon 6,6 (Hollóczki and Gehrke 2019 ). Furthermore, the behavior of PE-NP in various solvents was explored through molecular modeling, revealing that in micro-structured amphiphilic liquids, e.g., ionic liquids, control over the disintegration (i.e., disentanglement) of NP analytes into free polymer chains can be achieved, which could be applied to extraction strategies for analytical purposes (Elfgen et al 2020 ).…”

Efficient Extraction and Analysis of Nanoplastics by Ionic Liquid-Assisted Cloud-Point Extraction Coupled with Electromagnetic Heating Pyrolysis Mass Spectrometry

“…22 In addition, molecular modeling has suggested that ILs can extract nanoplastics. 23 ILs have been combined with CPE, which increases the extraction ability of surfactants. This has been demonstrated for the extraction of five monoterpene glycosides from the Paeonia suffruticosa flower with a detection limit of 0.1 ng/mL.…”

“…Silver nanoparticles with recoveries of 75.7%–96.6% in consumer products were achieved with the use of ILs . In addition, molecular modeling has suggested that ILs can extract nanoplastics . ILs have been combined with CPE, which increases the extraction ability of surfactants.…”

Optimizing the method for removing MSNs templates using an ionic liquid ([C4mim]Cl)

“…In this context, several researchers have used ILs as extractants by adjusting the strength between the ILs and the nanoplastics. This has been achieved by changing the length of the alkyl side chain of the IL, and the nanoplastics could then be removed from aqueous solution [50]. From the above works, it can be seen that ILs are widely used within the fields of separation and extraction.…”