Degradation of dyeing wastewater by sodium persulfate activated with Fe@MXene

Rapid activation degradation of C.I. Reactive Black 5 (RB5) wastewater with sodium persulfate (SPS) was accomplished using iron-doped MXene (Fe@MXene). The study systematically explored the influence of SPS concentration, Fe@MXene concentration, Fe-to-MXene molar ratio, initial pH, and ion species on the RB5 degradation percentage. The RB5 simulated dye solution, using 3 g/L SPS and 200 mg/L Fe@MXene mixture at 25 degrees C, stirred for 30 min, resulting in a degradation percentage of up to 99.6 %. Fe@MXene synthesis led to Ti-O bond formation and a 19.04 % reduction in crystallinity due to titanium reduction and iron incorporation. The Fe@MXene catalyst significantly accelerated SPS activation through enhanced electron transfer processes, facilitated by the distinctive structural and functional attributes of MXene, which enable the continuous reduction of Fe3+ to Fe2+. This process promotes the generation of sulfate radicals (SO4 center dot-), hydroxyl radicals (center dot OH), and singlet oxygen (O-1(2)), which were identified as the key reactive species driving dye degradation. When using this system to degrade dyeing wastewater, the types of dyes and inorganic salts only affect the degradation rate, not the final degradation percentage. During the five cycles, Fe leaching consistently reached 2.27 mg/L, leading to a 6.75 % decrease in degradation percentage by the fifth cycle compared to the first. The treated dyeing bath was reused in a new dyeing, and excellent coloration property was observed. This study not only enhances the understanding of the catalytic reaction of Fe@Mxene but also provides a highly efficient process for dyeing wastewater treatment, showing promising application prospects.