Solvent-free synthesis of TiO2 nanoparticles embedded MWCNTs with enhanced photocatalytic activity for bacterial disinfection

[Display omitted] •Nanocomposite with TiO2 NPs encapsulated in MWCNTs internal channels for photocatalyst is fabricated.•The fabrication process is facile and is green, solid chemistry without using a solvent.•Selective growth of anatase crystal phase through heating temperature control.•Successful removal of organic dyes and disinfection of biohazardous substances due to photocatalytic effect. Sustainable energy has been widely researched to address issues caused by population growth and rapid industrialization. Among them, photocatalysis using solar energy has been considered promising. We developed a hybrid photocatalyst by combining titanium dioxide (TiO2) with carbon nanotubes (CNTs), known for their excellent adsorption performance. A unique structure encapsulating TiO2 nanoparticles (NPs) within the inner space of multi-walled carbon nanotubes (MWCNTs) was developed via a facile, solvent-free method, conforming to green chemistry principles. Except purification and modification of the CNTs, the particle formation process is solvent-free, making this method remarkably simple and environmentally friendly. This arrangement enhances stability and recyclability, maintaining over 90 % efficiency up to the 3rd cycle. X-ray diffraction (XRD) analysis confirmed that the TiO2 NPs exhibited a crystalline phase, forming exclusively anatase. The defects in the outer walls of the MWCNTs in the composite, coupled with their large specific surface area and dangling bonds, endow them with high adsorption capacity and photocatalytic activity when combined with TiO2 NPs. The MWCNTs@TiO2 composites achieved over 99 % inactivation of Escherichia coli in 60 min and bacteriophage MS2 in 30 min, along with dye adsorption/decomposition. This method offers a distinctive platform for photocatalytic degradation in biological applications and water treatment.