MIL-100(Fe)/melamine sponge composites for adsorption and detection of malachite green

Malachite green (MG) is a toxic contaminant commonly found in aquaculture, making its effective removal and detection crucially important. In this study, MIL-100(Fe) was synthesized via a microwave-assisted hydrothermal method under optimized conditions (150 °C, 200 W, 30 min; FeCl₃·6H 2 O:H₃BTC = 2:3). The resulting material exhibited excellent structural stability, a high specific surface area (1169.9 m 2 /g), and a remarkable MG adsorption capacity of 714.29 mg/g. To enable practical application and reusability, MIL-100(Fe) was immobilized onto a melamine sponge (MeS) using polyvinylidene fluoride (PVDF) as binding agent, forming a recyclable MeS/PVDF/MOF composite. When applied for solid-phase extraction of MG in conjunction with UV detection, the composite demonstrated high recovery rates (92.1–99.4 %), a low detection limit (2.29 μg/L), and consistent performance with over 80 % recovery after six reuse cycles in both real fish and wastewater samples. This study presents a simple, efficient and sustainable strategy for the adsorption and detection of MG in aquatic food matrices.