BACKGROUND The non-modified titanium dioxide (TiO2) nanotube (TNT) and silver (Ag)-modified TNT samples were fabricated via an alkaline hydrothermal process. The synthesized samples had a high Brunauer-Emmett-Teller surface area since the resulted TNT was free of calcination, which is different from the traditional synthesized method. The specific surface area of non-modified TNT and Ag-modified TNT samples were 392 and 330 m(2) g(-1), respectively. RESULTS The results indicated that anatase phase, cubic silver chloride (AgCl) and Ag co-existed in the Ag-modified TNT sample. In contrast, non-modified TNT sample has only anatase phase. The OH groups, pre-adsorbed water, and oxygen vacancies can be found on the surface of all samples. The Ag-modified TNT sample showed to have higher removal efficiencies than that of non-modified TNT sample for gas-phase elemental mercury, carcinogenic malachite green, crystal violet and mixtures of dyes. CONCLUSION Although specific surface area of non-modified TNT was larger than that of Ag-modified TNT, the Ag-modified TNT possessed a high-performance photocatalyst due to the electron-hole pairs separation efficiency increase. (c) 2019 Society of Chemical Industry