Highly efficient extraction of phenolic compounds by use of magnetic room temperature ionic liquids for environmental remediation

Abstract

A hydrophobic magnetic room temperature ionic liquid (MRTIL), trihexyltetradecylphosphonium tetrachloroferrate(III) ([3C6PC14][FeCl4]), was synthesized from trihexyltetradecylphosphonium chloride and FeCl3·6H2O. This MRTIL was investigated as a possible separation agent for solvent extraction of phenolic compounds from aqueous solution. Due to its strong paramagnetism, [3C6PC14][FeCl4] responds to an external neodymium magnet, which was employed in the design of a novel magnetic extraction technique. The conditions for extraction, including extraction time, volume ratio between MRTIL and aqueous phase, pH of aqueous solution, and structures of phenolic compounds were investigated and optimized. The magnetic extraction of phenols achieved equilibrium in 20 min and the phenolic compounds were found to have higher distribution ratios under acidic conditions. In addition, it was observed that phenols containing a greater number of chlorine or nitro substitutents exhibited higher distribution ratios. For example, the distribution ratio of phenol (DPh) was 107. In contrast, 3,5-dichlorophenol distribution ratio (D3,5-DCP) had a much higher value of 6372 under identical extraction conditions. When compared with four selected traditional non-magnetic room temperature ionic liquids, our [3C6PC14][FeCl4] exhibited significantly higher extraction efficiency under the same experimental conditions used in this work. Pentachlorophenol, a major component in the contaminated soil sample obtained from a superfund site, was successfully extracted and removed by use of [3C6PC14][FeCl4] with high extraction efficiency. Pentachlorophenol concentration was dramatically reduced from 7.8 μg.mL−1 to 0.2 μg.mL−1 after the magnetic extraction by use of [3C6PC14][FeCl4].

GUMBOS matrices of variable hydrophobicity for matrix‐assisted laser desorption/ionization mass spectrometry

“…All of these compounds absorb over a similar wavelength range as compared to a CHCA matrix. The performance of our materials as MALDI matrices, reported in the subsequent sections, is compared with that of CHCA because CHCA is a commonly used MALDI matrix for low molecular weight biomolecule applications . The molar absorptivities of all compounds at 355 nm are also listed in Table .…”

“…The performance of our materials as MALDI matrices, reported in the subsequent sections, is compared with that of CHCA because CHCA is a commonly used MALDI matrix for low molecular weight biomolecule applications. [12,37] The molar absorptivities of all compounds at 355 nm are also listed in 2 ] is much lower than that of CHCA. Hence, the molar absorptivity is dependent on the counterion.…”

“…In other words, organic salts with melting points up to 25 °C are referred to as RTILs, while solids with melting points from 25 to 250 °C are referred to as GUMBOS. GUMBOS and RTILs have been used for a variety of applications, primarily due to the ease with which these materials can be engineered for specific needs . The hydrophobicity of such compounds can be easily tuned simply by changing the counterion, which results in savings of time and energy.…”

“…GUMBOS and RTILs have been used for a variety of applications, primarily due to the ease with which these materials can be engineered for specific needs. [35][36][37][38] The hydrophobicity of such compounds can be easily tuned simply by changing the counterion, which results in savings of time and energy. Thus, this approach is an economical method to obtain a desired product with excellent yield.…”

Extraction of Phenols from Water with Functionalized Ionic Liquids

“…]12 to extract phenols from water. The distribution ratios (D) of these ILs and those of [C 4 C 11 OHim]BF 4 (in the presence of 30% NaCl at pH 7.0 and a phase ratio of 10:1) were consequently compared, and the results are listedTable 3.…”