Electrostatic self-assembly of TiO2 nanoparticles onto carbon spheres with enhanced adsorption capability for Cr(VI)

► High quality TiO2 nanoparticles are synthesized via a nonaqueous sol-gel method. ► TiO2 nanoparticles are assembled onto carbon spheres in ultrapure water at pH=4. ► These hybrid spheres show an enhanced adsorption capacity for Cr(VI). ►The adsorption capacity decreases significantly with the increasing of pH value.