A simple and effective method for Escherichia coli inactivation in aqueous medium using natural based superparamagnetic coagulant

Escherichia coli is often used as a faecal indicator bacterium to evaluate water quality and is used as a measure to predict the presence of pathogens and their inactivation/removal is important to ensure safe drinking water. In this study γ–Fe 2 O 3 nanoparticles were synthesized by a modified sol–gel method, followed by a subsequent functionalization process with Moringa oleifera (MO) integral seed extract and without ethanol‐extracted oil (MO‐et) for the creation of a new coagulants with antibacterial activity (γ–Fe 2 O 3 –MO and γ–Fe 2 O 3 –MO(et)). These coagulants were characterized according to their composition, morphology, structure, and surface charge. Coagulation/flocculation tests were performed with subsequent sedimentation under the influence of an external magnetic field for E. coli inactivation/removal. The results indicate that there was total inactivation of E. coli for raw water and removal of 88 and 93% for synthetic water using the coagulants γ–Fe 2 O 3 –MO and γ–Fe 2 O 3 –MO (et) respectively, demonstrating that the coagulant properties of MO and the superparamagnetic behavior of nanoparticles of γ‐Fe 2 O 3 increased the activity of the new material, favoring the inactivation/removal of E. coli in the water treatment.