Persulfate-enhanced photodegradation of para-nitroaniline in wastewater using AgCuFe2O4@MC/AC as a newly synthesized heterogeneous magnetic nanophotocatalyst: Mechanism study and bioassay of effluent
Nazanin Rahmati, Majid Hashemi, Alireza Nasiri
Abstract
Para -nitroaniline (PNA), even at very low concentrations, is toxic and can lead to significant health and environmental issues. This research investigated the photodegradation of PNA using an AgCuFe 2 O 4 @MC/AC nanophotocatalyst synthesized via the co-precipitation technique with microwave assistance. Various analyzers, including XRD , BET, FESEM-EDS, Mapping, Linescan, FTIR, DRS, and VSM, were employed to characterize the synthesized catalyst's structure. Subsequently, factors influencing PNA's photocatalytic removal process were optimized. The synthesized catalyst measured approximately 50 nm, exhibited a crystalline structure, a high specific surface area (435.77 m 2 /g), magnetic strength (1.713 emu/g), a pseudo -spherical shape, and suitable optical activity with a bandgap of 3.45 eV. Under optimal conditions (10 mg/L initial PNA concentration, catalyst dosage of 0.04 g/L, 2 mM persulfate dose, pH = 7, and 90 min of irradiation), the removal efficiency of PNA reached 84.55 % and 67.99 % in synthetic and real wastewater samples, respectively. The kinetics of the process followed pseudo -first order and Langmuir-Hinshelwood models. The magnetic nanophotocatalyst demonstrated strong chemical stability and recoverability. The active radical species in the process mechanism was identified as sulfate radical . The toxicity assessment results indicated that the effluent from the process is safe, as the mortality rates for Daphnia and Artemia were 48 % and 23 %, respectively, after 72 h at the maximum effluent concentration. The AgCuFe 2 O 4 @MC/AC magnetic heterogeneous nanophotocatalyst exhibits high efficiency in degrading PNA, and the effluent poses minimal environmental risk to living organisms. Consequently, wastewater containing aniline compounds and other emerging pollutants with a similar structure can be treated using this technique.