One-Pot Green-Synthesis of Supported Reductive Biogenic Iron-Based Materials for the Removal of Cr(VI)

Development of environmentally friendly materials for efficient pollutant removal is crucial. In this work, a new one-pot green-synthesis of iron-based materials with a reductive/adsorption potential was developed and tested for remediation of Cr(VI) in water. Biogenic iron particles (BioFe) and BioFe supported on raw montmorillonite (BioFe-MMT) were synthesized using a ferric reducing bacteria consortium (FRB), and their structures were extensively characterized by Mössbauer spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Moreover, the microbial community in the consortium was assessed. Results indicated that BioFe-based materials presented dispersed cubic baricite microparticles containing Fe(II) and Ca2+ in their structure, making them ideal for Cr(VI) remediation. The removal efficiency of Cr(VI) from water by a combination of reduction and adsorption processes using the synthesized materials was evaluated through kinetics experiments. The removal of total chromium was more efficient using supported BioFe than using unsupported BioFe and no dependence with dissolved O2 was detected. The preparation of iron particles with excellent chromium removal performance by a new biobased synthesis could lead to a low-cost and environmentally friendly remediation technology.