Adsorption-based thermal energy conversion systems offer a sustainable solution for space heating and cooling applications. However, due to the limited performance of solid adsorbents, the large-scale application of this technology still requires further research. To address this challenge, we developed a composite adsorbent by integrating a graphene oxide (GO)-modified metal-organic framework (MIL-101(Cr)) with LiCl. The material was characterized using a variety of techniques to assess its improvement in three areas: water adsorption performance, heat propagation rate and stability. The synthesized material was systematically characterized to evaluate three key performance parameters: water adsorption capacity, thermal conductivity, and cyclic stability. The optimized composite LMG-3 (90 wt% LiCl) exhibits a tenfold increase in water absorption capacity compared to MIL-101(Cr)@GO at P/P 0 = 0.3. The introduction of GO significantly increases the heat diffusion coefficient, and the material exhibits excellent cyclic stability and inhibits salt deliquescence, demonstrating its potential for adsorptive thermal storage applications.
The occurrence of numerous antibiotics, such as sulfonamides (SAs), in environmental water has recently heightened concerns in consideration of their potential threat to human health and aquatic ecosystems. The removal of pharmaceuticals by adsorption comprises some of the most promising techniques because of their easy regeneration, low cost, and high efficiency. In this work, MIL-101(Cr)@GO, with a high surface area, was synthesized. Its adsorption properties toward three SAs were examined in batch adsorption experiments to probe the underlying factors of adsorption behavior and the mechanism for the first time. The pronounced factors that influenced the adsorption and removal process were investigated. The adsorption kinetics and isotherms were studied in order to characterize the operation. The adsorption kinetics demonstrated that the adsorption process would match the pseudo-second-order kinetic model. Furthermore, the adsorption was spontaneous, entropy was decreased, and the process was exothermic, and the equilibrium data was more appropriate described by the Freundlich isotherm model. Moreover, the adsorption–desorption of MIL-101(Cr)@GO could be consecutively cycled at least five times. MIL-101(Cr)@GO exhibited remarkable removal efficiency compared to MIL-100(Fe), MIL-101(Cr), and other adsorbents. These results demonstrated that MIL-101(Cr)@GO would be a promising adsorbent for the removal of sulfonamides from water samples and even for environmental protection.
As a novel material, metal-organic framework/graphite oxide (MIL-101(Cr)@GO) has great potential for the pretreatment of trace analytes. In the present study, MIL-101(Cr)@GO was synthesized using a solvothermal synthesis method at the nanoscale and was applied as sorbent in the dispersive micro-solid phase extraction (DMSPE) for the enrichment of the trace sulfonamides (SAs) from milk samples for the first time. Several experimental parameters including kinds of sorbents, the effect of pH, the amount of MIL-101(Cr)@GO, ionic strength , adsorption time, desorption solvent and desorption time were investigated. Under the optimal conditions, the linear ranges were from 0.1 to 10 μg/L, 0.2–20 μg/L or 0.5–50 μg/L for the analytes with regression coefficients ( r ) from 0.9942 to 0.9999. The limits of detection were between 0.012 and 0.145 μg/L. The recoveries ranged from 79.83% to 103.8% with relative standard deviations (RSDs)<10% ( n =3). MIL-101(Cr)@GO exhibited remarkable advantages compared to MIL-101(Cr), MIL-100(Fe), activated carbon and other sorbent materials used in pretreatment methods. A simple, rapid, sensitive, inexpensive and less solvent consuming method of DMSPE-ultra-high performance liquid chromatography-tandem mass spectrometry (DMSPE-UHPLC-MS/MS) was successfully applied to the pre-concentration and determination of twelve SAs in milk samples.