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摘要
The adsorption of 2,4,6-trichlorophenol (2,4,6-TCP) on synthesized magnetic mesoporous silica (Fe3O4/SiO2/m-SiO2, MMS) composites and the regeneration of its adsorption capacity through direct UV photolysis was performed in this work. MMS exhibited good performance in removing 2,4,6-TCP from aqueous solutions. The adsorption ratio of 2,4,6-TCP was determined to be influenced by aquatic pH, dissolved humic acids, ionic strength, temperature, and the loaded adsorbents. The adsorption isotherm fit the Freundlich and Polanyi-Manes model better than the Langmuir model, which indicated that the adsorption of 2,4,6-TCP was more likely a pore-filling process. The calculated adsorbed capacity for 2,4,6-TCP on MMS was 55mg/g. Direct UV photolysis could decompose the adsorbed 2,4,6-TCP and later regenerate the adsorption capacity of MMS to a certain degree; however, the outer mesoporous silica layer was not UV-persistent, and large parts of the mesoporous silica layer were also shown to be corrupted from the Fe3O4/SiO2 core. Therefore, after long duration UV irradiation, the adsorption of 2,4,6-TCP on regenerated MMS was much lower than on freshly synthesized MMS. These results suggest that the photostability of magnetic core-shell-like nanocomposites should be investigated because parts of the composites might leach into the bulk phase during practical use and cause potential environmental risks, similar to other well-known nanomaterials.
