Metal–organic framework MIL-101(Cr) as a sorbent of porous membrane-protected micro-solid-phase extraction for the analysis of six phthalate esters from drinking water: a combination of experimental and computational study

Abstract

An attractive metal-organic framework (MOF) MIL-101(Cr) material was synthesized at the nanoscale and applied as a sorbent in the porous membrane-protected micro-solid-phase extraction (μ-SPE) device for the pre-concentration of phthalate esters (PAEs) in drinking water samples for the first time. Parameters influencing the extraction efficiency, such as the selection of sorbent materials, pH adjustment, the effect of salt, magnetic-stirring extraction time, the desorption solvent and the desorption time, were investigated. Under the optimum conditions, the limits of detection from gas chromatography-mass spectrometric analysis for PAEs varied from 0.004 to 0.02 μg L(-1). The linear ranges were from 0.1 to 50 μg L(-1) or from 0.2 to 50 μg L(-1) for the analytes with the relative standard deviations fluctuating from 0.8 to 10.9% (n = 5). The enrichment factors (EFs) for the target PAEs were varied from 143 to 187. MIL-101(Cr) exhibited remarkable advantages compared to activated carbon and MIL-100(Fe). On the other hand, the computational method was first used to predict the adsorption of MIL-101(Cr) towards PAEs. The molecular interactions and the free binding energies between MIL-101(Cr) and PAEs were observed and calculated in terms of the molecular modeling method. MIL-101(Cr) showed high potential in the analysis of PAEs at trace levels in drinking water. The computational result was consistent with the detected enrichment factors. The computational modeling accurately predicted the extraction efficiency of MOF-based material towards the target analytes. Therefore, the combination of experimental and computational study provided a new strategy on the trace contaminant analysis.

Replacement of Chromium by Non-Toxic Metals in Lewis-Acid MOFs: Assessment of Stability as Glucose Conversion Catalysts

“…The differences in relative intensity between the low angle peaks (at less than 6 • 2θ ) and those at higher angle (greater than 8 • 2θ ) in the measured pattern compared to the simulated pattern is accounted for by the presence of solvent in the as-prepared sample; in contrast, the simulated pattern is for an idealised guest-free framework. These X-ray powder patterns are typical of MIL-101 samples reported in the literature [44][45][46]. There is also evidence in the PXRD for the presence of an impurity phase in the sample, which we identify below as being MIL-88B ( Figure 1) [47].…”

K6P2W18O62 encapsulated into magnetic Fe3O4/MIL-101 (Cr) metal–organic framework: a novel magnetically recoverable nanoporous adsorbent for ultrafast treatment of aqueous organic pollutants solutions

“…21 MOFs are a new class of nanoporous materials consisting of metal ions or clusters coordinated to organic ligands, and they have attracted considerable attention in the adsorption and removal of organic pollutants due to their ultrahigh surface areas, ultrahigh porosity, and tunable pore size. [22][23][24] Among the thousands of MOFs that have been introduced so far, one of the most prominent materials is MIL-101 (Cr). 25 MIL-101 (Cr) has been utilized as an adsorbent due to it having certain attractive features, such as large pore size, ultrahigh surface area, excellent chemical stability, and low cost.…”

A green metal–organic framework to monitor water contaminants

“…16 Recent studies have tried to correlate the structure of MOFs with that of pollutants intended to be monitored, with the goal of targeting MOFs for selective monitoring. 9,17,18 Such studies pointed out the difficulties in predicting the adsorption of a target analyte (for analytes initially present in a water media) into a specic MOF material. In any case, the MOF's exibility, the presence of unsaturated metal sites, large pore volumes, and a hydrophobic environment around the pores seem to be adequate characteristics when intending a MOF as generic sorbent for environmental monitoring.…”