In Situ-Grown MIL-100(Fe) for Interfacial Regulation of KTBC and Its Adsorption Performance and Mechanism for Xylenol Orange Removal.

In this study, a MIL-100(Fe)@KTBC composite was successfully fabricated via an in situ hydrothermal method using KOH-activated tomato-biochar-derived carbon (KTBC) as the support, and was applied for the efficient adsorptive removal of xylenol orange (XO) from water. Characterization by SEM, XRD, FTIR, XPS, and BET confirmed that MIL-100(Fe) was successfully loaded onto the KTBC surface, and the resulting composite exhibited a well-developed porous structure, abundant functional groups, and good thermal stability. Adsorption experiments showed that MIL-100(Fe)0.5@KTBC delivered the optimal performance, with a maximum adsorption capacity of 246.12 mg/g; high removal efficiency was achieved at pH 4.0 and an adsorbent dosage of 0.4 g/L. The adsorption process followed pseudo-second-order kinetics and the Langmuir isotherm model, indicating spontaneous, endothermic, monolayer adsorption dominated by chemisorption. The composite also demonstrated strong resistance to interfering ions and favorable reusability. This work provides a scientific basis for the development of efficient and stable biochar-based MOF composites for the treatment of printing and dyeing wastewater.