The systematic analysis of different organic solvents influence on the morphology of TiO2 nanotubes (TNTs) via hydrothermal synthetic route with the addition of alkaline solution and commercial TiO2 nanoparticles is performed through characterizations. The photocatalytic activity of TNTs was investigated by degradation of Orange II aqueous solution under UV-light irradiation. The degradation kinetic data was modelled in pseudo-first order and pseudo-second order kinetics equations which reveal that degradation onto TNTs followed pseudo-first order kinetic model with correlation coefficient more than 0.99. Furthermore, the equilibrium data of Orange II onto TNTs was analyzed using Langmuir, Freundlich and Temkin isotherm models suggesting that Langmuir isotherm model provides excellent correlation of the experimental data with maximum degradation capacity of 15.726 mg/g. The activation energy was found to be 24.48 kJ/mol, suggesting that photocatalytic degradation follows physisorption mechanism. Thermodynamic parameters: enthalpy (�H°) was 44.175 kJ mol�1, entropy (�S°) was 159.850 Jmol�1K�1 and the values of Gibb's free energy (�G°) were �47.592, �49.988 and �52.386 kJ mol�1 at 298, 313 and 328 K, respectively, suggesting spontaneous and endothermic process. The rise in temperature was found to be more feasible and favorable for photocatalytic degradation of Orange II onto TNTs. Thus, based on present research, solvent-based TNTs would be promising candidates for wastewater treatment. © 2018 Elsevier Ltd