Efficient removal of veterinary drugs from aqueous solutions using magnetically separable carbonaceous materials derived from cobalt and iron metal-organic frameworks

Rapid synthesis of carbon-based magnetic materials derived from cobalt and iron metal-organic frameworks (MOFs), ZIF-67, and MIL-100(Fe), by microwave-assisted method, followed by carbonization under a N-2 atmosphere is described in this study. The carbon-derived MOFs (CDMs) were evaluated for the removal of the emerging pollutants sulfadiazine (SDZ) and flumequine (FLU) used as veterinary drugs. The study aimed to link the adsorption behavior with their surface properties and elemental composition. C-ZIF-67 and C-MIL-100(Fe) showed hierarchical porous structures with specific surface areas of 295.6 and 163.4 m(2) g(-1), respectively. The Raman spectra of the CDMs show the characteristic D and G bands associated with defect-rich carbon and sp(2) graphitic carbon, respectively. The CDMs exhibit cobalt species (Co3O4, CoO, and Co) in C-ZIF-67 and iron species (Fe2O3, Fe3O4, and Fe) in C-MIL-100 (Fe) which are related to the magnetic behavior of CDMs. C-ZIF-67 and C-MIL-100 (Fe) had saturation magnetization values of 22.9 and 53.7 emu g(-1), respectively, allowing easy solid-liquid separation using a magnet. SDZ and FLU removal rates on CDMs follow pseudo-second-order kinetics, and adsorption isotherms fit the Langmuir model based on regression coefficient values. Adsorption thermodynamics calculations showed that the adsorption of SDZ and FLU by CDMs was a thermodynamically favorable process. Therefore, these properties of C-ZIF-67 and C-MIL-100 (Fe) and their regeneration ability facilitate their use as adsorbents for emerging pollutants.

Automated summary

This study describes the rapid synthesis of carbon-based magnetic materials derived from cobalt and iron metal-organic frameworks (MOFs) through a microwave-assisted method followed by carbonization. C-ZIF-67 and C-MIL-100 (Fe) exhibited hierarchical porous structures and specific surface areas. The carbon-derived MOFs (CDMs) showed cobalt and iron species, which contributed to their magnetic behavior. The CDMs demonstrated high adsorption capacities for sulfadiazine (SDZ) and flumequine (FLU), and the adsorption process was thermodynamically favorable. Thus, C-ZIF-67 and C-MIL-100 (Fe) have potential as adsorbents for emerging pollutants.