Photocatalytic performance of TiO2 supported on hexagonal mesoporous silicate (HMS) loaded by different concentrations of oak gall tannin (OGT) for degradation of direct yellow 86 (DY86) was studied (TiO2-OGT(x)-HMS, x = 0.3, 0.6,1 wt%). The results were also compared with the performance of TiO2 (p-25) and TiO2 supported on HMS. Photocatalysts were characterized by XRD, SEM, EDX and TEM analysis. The analysis showed that tannin was immobilized on the surface and TiO2 nanoparticles were distributed well on the surface of OGT-HMS without aggregation. It was concluded that photocatalytic reaction follows first-order kinetic and up to 120 mg/l, Langmuir-Hinshelwood (L-H) kinetic model is acceptable. (C) 2016 Elsevier B.V. All rights reserved.