Synthesis of magnetic metal-organic framework for efficient adsorption of disinfection by-products in water

The disinfection of drinking water is an important treatment process for protecting consumers from potential waterborne infectious and parasitic pathogens. However, the disinfection process may introduce disinfection byproducts (DBPs), which are harmful to human health. It is necessary to control the contents of DBPs and their precursors. In this study, we synthesized Fe3O4@SiO2@PDA@NH2-MIL-53(Fe) magnetic composites via layer-by layer self-assembly method. This green and eco-friendly materials were thoroughly characterized and used to adsorb the highly toxic DBPs, 2,6-dichloro-1,4-benzoquinone (2,6-DCBQ) and its precursors, bisphenol A and phenol. The maximum adsorption quantity of Fe3O4@SiO2@PDA@NH2-MIL-53(Fe) was up to 109.3 mg g-1 for 2,6-DCBQ, 82.4 mg g-1 for bisphenol A, and 64.8 mg g-1 for phenol. The saturation magnetization value of Fe3O4@SiO2@PDA@NH2-MIL-53(Fe) was 39 emu g-1, which could be fast magnetic separated. In addition, the adsorption process was fitted into the pseudo-first-order adsorption model and Freundlich equation, in which 7C-7C interaction, hydrogen bond and pore-filling were the main adsorption mechanisms. After 5 cycles, the adsorption rate of the as-synthesized magnetic composites is still more than 80%. Due to its fast and strong adsorption capability, excellent stability, and easy separation ability from water, Fe3O4@SiO2@PDA@NH2-MIL-53(Fe) magnetic composites have the potential to be a promising adsorption material for removing the disinfection byproducts in future.