Carbon dots-doped melamine–formaldehyde microsphere as a dual functional material for sensing and adsorption of oxytetracycline

The abuse of oxytetracycline (OTC) leaves serious environmental residues and triggers accumulation in organisms, constituting a threat to human health. Constructing an effective platform based on dual-functional materials for monitoring and removing OTC residues is a preferable solution. Herein, we proposed a novel composite material by doping carbon dots (CDs) into melamine–formaldehyde microsphere (MFM) through a one-pot method and named CDs@MFM, which inherited the fluorescence property of CDs and porous structure of MFM simultaneously. CDs@MFM demonstrated dual functions for the detection and removal of OTC concurrently within a few minutes, with its performance compared in detail with bare CDs and MFM as controls. By virtue of the pre-enrichment effect attributed to its porous structure, CDs@MFM exhibited a lower detection limit for OTC than bare CDs (0.027 mg/L vs 0.067 mg/L) and a higher adsorption capacity than MFM (73.01 mg/g vs 68.76 mg/g) resulting from more affiliated functional groups available for OTC provided by the CDs. Overall, CDs@MFM has proven to be an efficient and convenient candidate capable of monitoring and removing OTC synchronously, and this work offers an avenue for the design of dual-functional materials in the field of environmental science.