Synthesis and application of choline chloride based deep eutectic solvents in liquid-liquid and solid-liquid assisted extraction of organophosphorus flame retardants from landfill leachate and sediment

Innocentia Velaphi Sibiya, Adegbenro Peter Daso, Okechukwu Jonathan Okonkwo

Research output: Contribution to journalArticlepeer-review

Abstract

The extraction of organic pollutants from environmental samples using green solvents has received a lot of interest recently. Simply said, this is due to their extremely low toxicity and volatility when compared to the common organic solvents. Therefore, many extraction exercises now include ionic solvents, as well as the more current deep eutectic solvents (DES). Hence, the current study reports on 1) the synthesis and characterisation of choline chloride/oxalic acid (1:1) and choline chloride/urea (1:2) deep eutectic solvents and 2) their application in liquid-liquid and solid-liquid assisted extraction of 14 targeted OPFRs from landfill leachate and sediment samples. The densities, refractive indices and melting points of the DES measured were 1.11 ± 0.15 g/mL, 1.14 ± 0.10 g/mL; 1.50 ± 0.12, 1.45 ± 0.20; and 12 ± 0.05°C, 35 ± 0.06–55 ± 0.05°C for choline chloride/urea (1:2) and choline chloride/oxalic acid (1:1) respectively. Choline chloride/urea (1:2) and choline chloride/oxalic acid (1:1) viscosities were 87.0 ± 0.20 kg·m −1·s −1 and 13.5 ± 0.14 kg·m −1·s −1 respectively. 1H NMR and FTIR confirmed the structures of the two DES. Recoveries using internal standards dTPP, dTBP, dTPrP and 13C18MTPP ranged from 59.9 ± 7.41–103 ± 5.32%; whereas the percent recoveries using CRM ranged from 85.7–117%. In the leachate (510–1433 ng/L) and sediment (725–1224 ng/g dw) samples from each landfill, 14 and 13 targeted OPFRs, respectively, were detected. The high recoveries and extraction of OPFRs demonstrated by the two DES imply that these could replace conventional organic solvents used to extract OPFRs from environmental media.

Original languageEnglish
JournalInternational Journal of Environmental Analytical Chemistry
Early online date6 Oct 2022
DOIs
Publication statusE-pub ahead of print - 6 Oct 2022

Keywords

  • Characterisation
  • DES
  • Landfill leachate and sediment
  • OPFR extraction
  • Synthesis

ASJC Scopus subject areas

  • Analytical Chemistry
  • Environmental Chemistry
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Soil Science
  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

Fingerprint

Dive into the research topics of 'Synthesis and application of choline chloride based deep eutectic solvents in liquid-liquid and solid-liquid assisted extraction of organophosphorus flame retardants from landfill leachate and sediment'. Together they form a unique fingerprint.

Cite this