ZIF-8 derived carbon@3D-printed columns as efficient continuous-flow adsorbents of parabens from water

In this study, we report a novel and cost-effective solution for removing parabens from water by combining MOF-derived porous carbons and 3D printing. In addition to being easy to prepare, the resulting 3D-printed device, with a cube-array structure, can also be fabricated in a robust column format for flow-through extraction of pollutants. Using an in-situ growth method, ZIF-8 MOF was directly deposited onto a 3D-printed device, achieving a stable and durable integration of the MOF onto the device. After the carbonization process, fully functional devices were obtained, entirely coated with a zinc-free carbon layer derived from ZIF-8, exhibiting both micro- and mesoporosity. c-ZIF-8@3D-printed cubes exhibited fast adsorption kinetics in batch conditions, achieving over 90 % extraction of ethylparaben within just 1 h, thanks to the mesoporosity of the obtained ZIF-8 derived carbon, as well as the possibility of establishing π-π interactions between it and the pollutant. Continuous-flow experiments demonstrated that c-ZIF-8@3D-printed columns showed high extraction efficiency for four parabens, maintaining removal rates between 83-92 % after 10 cycles. The columns also showed easy regeneration, enabling multiple uses of the 3D support and enhancing both the sustainability and efficiency of the water treatment process. Finally, the c-ZIF-8@3D-printed column was also tested for the simultaneous extraction of parabens from different real water samples with excellent results, confirming its potential for practical applications in water treatment.