In this work, a novel NH 2 -MIL-53(Al) incorporated poly(styrene-divinylbenzene-methacrylic acid) (poly(St-DVB-MAA)) monolith was prepared via chemical fabrication. Moreover, it has been efficiently applied to the in-tube solid-phase microextraction (SPME) for online coupling with high-performance liquid chromatography (HPLC) to the direct determination of five estrogens in human urine samples. The NH 2 -MIL-53(Al)-polymer monolith was suitable for in-tube SPME owing to its good permeability, high extraction efficiency, chemical stability, good reproducibility and long lifetime. The extraction conditions including extraction solvent, pH of sample solution, flow rate of extraction and desorption, and desorption volume were investigated. Under the optimum conditions, the enrichment factors were 180–304 and saturated amounts of extraction were 2326–21393 pmol for estriol , 17β-estradiol, estrone , ethinyl estradiol and progesterone , respectively. The adsorption mechanism was also explored which contributed to its strong extraction to target compounds. The proposed method had low limit of detection (2.0–40 ng/L) and good linearity (with R 2 between 0.9908 and 0.9978). Four endogenous estrogens were detected in urine samples and the recoveries of all five analytes were ranged from 75.1–120% with relative standard deviations (RSDs) less than 8.7%. The results showed that the proposed online SPME-HPLC method based on NH 2 -MIL-53(Al)-polymer monolithic column was highly sensitive for directly monitoring trace amount of estrogens in human urine sample.
This study demonstrates a sustainable strategy for synthesizing MIL-53(Al) and ZSM-5 zeolite through dual-waste synergy using coal fly ash (CFA) and waste polyethylene terephthalate (PET). A sequential alkaline fusion-acid leaching protocol selectively fractionated CFA into aluminum-rich solutions and silica residues, while alkaline hydrolysis of PET liberated terephthalic acid (PTA) as organic ligands. The Al 3+ -PTA coordination under solvothermal conditions produced MIL-53(Al)(CFA-PET) exhibiting well-defined 1D rhombic channels with a high BET surface area (1303 m 2 ·g −1 ), whereas hydrothermal crystallization of silica residues yielded ZSM-5(CFA), which formed spherical aggregates composed of 100 nm nanosheets with 89.9 % yield and a surface area of 311 m 2 ·g −1 . Structural advantages were evidenced by exceptional adsorption performance: MIL-53(Al)(CFA-PET) achieved 96.24 % methylene blue removal at pH 7 (250 mg·L −1 ), outperforming rhodamine B (30.8 %) and methyl orange (66.4 %), as well as reagent-synthesized MIL-53(Al) Che (91.99 %). Both materials demonstrated exceptional CO 2 capture capacities (4.23 mmol·g −1 for MIL-53(Al)(CFA-PET) vs. 2.37 mmol·g −1 for ZSM-5(CFA) at 273 K/1 bar), attributable to MIL-53′s flexible framework enabling dynamic pore adjustment and ZSM-5′s rigid microporous channels favoring molecular sieving. This work establishes a closed-loop strategy for converting industrial and plastic wastes into functionally differentiated porous materials through element-targeted process design.
In this work, computational and experimental methods were used to study the adsorption of estrogens and glucocorticoids on metal–organic frameworks (MOFs). Computer-aided molecular simulation was applied to predict the adsorption of eight analytes on four MOFs (MIL-101(Cr), MIL-100(Fe), MIL-53(Al), and UiO-66(Zr)) by examining molecular interactions and calculating free binding energies. Subsequently, the four water-stable MOFs were synthesized and evaluated as adsorbents for the target hormones in aqueous solution. As the MOF exhibiting the highest adsorption capacity in both computations and experiments, MIL-53(Al) was chosen as a sorbent to develop a dispersive micro-solid-phase extraction procedure coupled to ultra-performance liquid chromatography tandem mass spectrometry for simultaneous determination of the target analytes in water and human urine samples. Experimental parameters affecting the extraction recoveries, including pH, ionic strength , MIL-53(Al) amount, extraction time, desorption time, and desorption solvent, were optimized. The optimized method provided a linear range of 0.005025–368.6 μg/L with good correlation coefficients (0.9982 ≤ r 2 ≤ 0.9992), and limits of detection (S/N = 3) and quantification (S/N = 10) of 0.0015–1.0 μg/L and 0.005–1.8 μg/L, respectively. The analyte recoveries were in the range of 80.6–98.4% in water samples and 88.4–93.2% in urine samples. Furthermore, MIL-53(Al) showed good stability over 10 extraction cycles (RSD < 10.0%). Good agreement between experimental measurements and computational results showed the potential of this approach for elucidating adsorption mechanisms and predicating extraction efficiencies for MOFs and targets, providing new directions for the development and utilization of MOFs.