Removal of lead (II) and toluidine blue from wastewater with new magnetic Bacillus niacini nano-biosorbent: Lead and toluidine blue removal by magnetic Bacillus niacini nano-biosorbent.

In this study, dead Bacillus niacini microorganisms were used to support the immobilization of magnetic iron nanoparticles, creating a magnetic nano-biosorbent for wastewater treatment through magnetic separation. Magnetic nano-biosorbent was characterized via scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectrophotometry, Brunauer–Emmett–Teller analysis, and vibration sample magnetometry techniques. The laser particle sizer confirmed a uniform distribution in the particle agglomerate sizes of magnetic iron nanoparticles and magnetic nano-biosorbent, affirming successful composite formation. Energy-dispersive X-ray spectroscopy confirmed Bacillus niacini specific elements, and Fourier transform infrared spectrophotometry indicated effective Bacillus niacini coating onto magnetic iron nanoparticles. Magnetic nano-biosorbent's efficacy for toluidine blue and lead (II) removal, considering pH, contact time, magnetic nano-biosorbent dosage, and initial pollutant concentrations, was assessed. Langmuir isotherms described toluidine blue and lead (II) biosorption optimally. Kinetic data matched the pseudo-first-order and pseudo-second-order models, implying multiple biosorption mechanisms. Magnetic nano-biosorbent displayed a biosorption capacity of 66.52 ± 0.68 mg/g for lead (II) and 82.88 ± 0.79 mg/g for toluidine blue. Reusability tests showed effective reuse for up to five cycles. The magnetic nano-biosorbent presents significant potential for wastewater treatment due to its high biosorption capacity, efficient removal, and cost-effective synthesis. [ABSTRACT FROM AUTHOR]