Synthesis of magnetic graphene oxide–TiO₂ and their antibacterial properties under solar irradiation

Highlights: • Magnetic graphene oxide–TiO₂ (MGO–TiO₂) composites were synthesized. • MGO–TiO₂ had excellent antibacterial activity toward Escherichia coli. • MGO–TiO₂ could effectively and rapidly separate from aqueous solution. • Carbonates and phosphates significantly reduced the bacterial survival rate. - Abstract: Titanium dioxide (TiO₂) has been intensively researched and increasingly used as antibacterial agent, but it suffers from separation inconvenience. Its effective removal from water after reaction while maintaining its high antibacterial activity becomes necessary. In this work, it was the first time the magnetic graphene oxide–TiO₂ (MGO–TiO₂) composites were prepared through a simple synthesis method. The results indicated that MGO–TiO₂ exhibited a good antibacterial activity against Escherichia coli. MGO–TiO₂ was found to almost completely inactivate the E. coli within 30 min under solar irradiation. The effect of inorganic ions present in E. coli suspension was also evaluated. Compared with other ions, HCO₃⁻ and HPO₄²⁻ had a greater influence on the antibacterial property