Dual function platform of NH2-MIL(Fe)-modified NH₂-PS for sulfamethoxazole elimination: Adsorption and Fenton-like oxidation

NH₂-MIL(Fe) is grafted onto amino-functionalized NH₂-PS resin to gain micro-nanoscale adsorbent. • SMX adsorption is favorable at pH 5.2–8.0 with an adsorption capacity of 250.61 mg·g −1 . • Hydrogen bonding and electrostatic attraction are the driving forces for SMX adsorption. • The Fe(III) centers in MOF endow NH₂-PS@NH₂-MIL(Fe) Fenton-like catalytic activity. Sulfonamide antibiotics (SAs) are ubiquitous in the aquatic environment and difficult to remove using conventional wastewater treatment processes. Adsorption and Fenton-like oxidation are efficient techniques for the elimination of SAs from water. In this study, a novel hierarchical micro-nano structural adsorbent was synthesized by grafting Fe-based MOFs (NH 2 -MIL(Fe)) onto amino-functionalized polystyrene-divinylbenzene resin (NH 2 -PS). The physicochemical properties and structural features of the composite (NH 2 -PS@NH 2 -MIL(Fe)) were systematically characterized by SEM, EDS, XRD, FTIR, BET and XPS, confirming the successful immobilization of NH 2 -MIL(Fe) on the PS surface and the presence of abundant active sites. The adsorption behavior of sulfamethoxazole (SMX) on NH 2 -PS@NH 2 -MIL(Fe) was evaluated under various conditions, including pH, adsorbent dosage, and coexisting anions. The adsorption process followed the pseudo-second-order kinetic model and Langmuir isotherm model, indicating a monolayer sorption with a maximum capacity of 250.6 mg·g −1 at pH 5.2 and thermodynamic analyses revealed that the adsorption was spontaneous and exothermic. Based on FTIR, XRD and XPS analyses, electrostatic attraction, hydrogen bonding, π–π stacking, and metal–ligand coordination/Lewis acid-base interaction collectively governed the adsorption of SMX. Furthermore, the Fe(III) centers endowed NH 2 -PS@NH 2 -MIL(Fe) Fenton-like catalytic activity. With the addition of H 2 O 2 , over 95% of SMX was eliminated rapidly from water in a wide pH range. Based on the dual functions, this material can efficiently remove SMX from surface water samples. These results highlight the great potential of NH 2 -PS@NH 2 -MIL(Fe) for efficient removal of sulfonamide antibiotics. Download: Download high-res image (319KB) Download: Download full-size image