Study on the degradation of tetracycline in aqueous solution using MIL-53(Fe) generated by needle–plate pulsed discharge

Tetracycline is one of the most widely used broad-spectrum antibiotics, and its continuous release into aquatic environments has become a serious environmental concern. Although metal–organic frameworks (MOFs) have demonstrated great potential for photocatalytic wastewater treatment, conventional synthesis methods generally suffer from long reaction times and limited capability for controllable defect engineering. To address these challenges, a needle–plate pulsed discharge plasma strategy was developed for the direct synthesis of MIL-53(Fe). The effects of key plasma discharge parameters on the structure, defect structure, and photocatalytic performance of MIL-53(Fe) were investigated. Under the optimized conditions (6.2 kV, 120 min, an FeCl 3 /TPA molar ratio of 1:1, and Ar atmosphere), the obtained MIL-53(Fe) catalyst achieved an average tetracycline degradation efficiency of 91.57% within 120 min. Structural and photoelectrochemical analyses revealed that the obtained MIL-53(Fe) exists plasma-induced oxygen-vacancy-related defects while preserving the crystal framework of MIL-53(Fe). These defects promoted the separation and migration of photogenerated charge carriers, thereby significantly enhancing the photocatalytic activity under xenon-lamp irradiation. These findings demonstrate that needle–plate pulsed discharge provides an effective strategy for the controllable synthesis of defect-regulated MIL-53(Fe), offering new opportunities for developing high-performance photocatalysts for antibiotic-contaminated wastewater treatment.