Study on the degradation performance of LaFeO 3 perovskite catalyst for reactive dyes and the dyeing performance of treated effluent

In this study, perovskite-type LaFeO 3 catalyst was successfully synthesized via the sol–gel method and applied to the catalytic degradation of reactive dye wastewater in the H 2 O 2 system. Experimental results revealed that, under optimized conditions (catalyst dosage = 0.3 g/L; H 2 O 2 concentration = 1 g/L; pH = 3; reaction temperature = 50°C; reaction time = 40 min), the degradation efficiency of Reactive Black WNN reached 99%. Mechanism analysis demonstrated that the catalyst could activate H 2 O 2 through the Fe 3+ /Fe 2+ redox cycle to produce hydroxyl radicals (·OH) and singlet oxygen ( 1 O 2 ). The synergistic effect of these two active species enabled the efficient degradation of dye molecules. In addition, LaFeO 3 exhibited excellent cycling stability; its degradation efficiency toward Reactive Black WNN remained 87% after five consecutive reuse cycles. The treated wastewater was recycled for cotton fabric dyeing. Compared with deionized water, the recycled wastewater showed no obvious differences in key dyeing performance indicators, including dye uptake, fixation rate, K / S , color difference (Δ E < 0.5), and color fastness to rubbing; this verified that the wastewater treated by this system possesses promising reusability for textile dyeing. Compared with the homogeneous Fenton system using ferrous sulfate, the LaFeO 3 catalytic system achieves comparable degradation efficiency, while featuring prominent advantages, such as no massive iron sludge production, low turbidity of effluent, recyclable catalyst, and convenient subsequent solid–liquid separation.