Sulfur and Carbon Co‐doped TiO₂ Composite Fabricated by Lignosulphonate and Its Suitability for Removal of Cadmium

Abstract

Highly toxic divalent cadmium causes serious environmental issues. To quickly monitor and/or efficiently remove this potentially toxic metal ion as well as to explore its interfacial chemistry with metal oxides, a sulfur and carbon co-doped titania (S/C-TiO 2 ) composite is synthesized via a facile sol-gel method with the assistance of sodium lignosulphonate (SLS). The prepared composite displays a well-crystallized TiO 2 nanostructure comprising the anatase phase. Both S and C, which are derived from the SLS template, are found to enter the TiO 2 lattice. The S/C-TiO 2 composite exhibits a porous structure with a wide pore size distribution. The newly synthesized composite shows adsorption capability for the potentially toxic metal Cd(II). The adsorption process requires <5 min to reach equilibrium. The measured equilibrium adsorption capacity is 19.42 mg g −1 , which is twice as high as that of bare TiO 2 . The removal efficiency is as high as 97%. Moreover, the materials are suitable for contaminated solutions over a wide range of pH values and various initial cadmium concentrations. A mechanism for the enhanced adsorption behavior is also proposed.