Microbial Treatment of Azo Dyes Using Biogenic Bimetallic Iron–Molybdenum Nanoparticles

Azo compounds have long posed a serious threat to publish health and the aquatic environment. Therefore, the adverse effects of azo compounds on public health have inspired the need to develop efficient and reliable treatment methods. Although various physicochemical treatment methods have been developed, bio-inspired environmentally friendly treatment method have not yet been reported. Here, we report the development of a novel azo compound treatment method using biogenic nanoparticles immobilized microorganism. Firstly, biogenic bimetallic iron–molybdenum nanoparticles immobilized Deinococcus radiodurans R1 (DR-FeMoNPs) were constructed. Next, physicochemical properties of FeMoNPs including specific surface area (53.627 m² g⁻¹), pore volume (0.3561 cm³ g⁻¹), and average pore diameter (19.205 nm) were thoroughly addressed. The resulting FeMoNPs-immobilized D. radiodurans R1 exhibited an 87.2% removal efficiency for Congo Red, with a maximum capacity of 172.4 mg/g. Additionally, the rapid degradation of residual H₂O₂, triggering Fenton-like reaction via biological scavenging mechanism, was confirmed. DR-FeMoNPs also demonstrated highly efficient removal of other types of azo compounds, such as Acid Orange 7 (99.4%) and Evans Blue (81.1%).