Adsorption and photocatalytic degradation of methylene blue over hydrogen–titanate nanofibres produced by a peroxide method

•Fabrication and characterisation of highly-adsorbent photoreactive nanofibres.•Bench scale adsorption and photocatalysis experiments for process optimisation.•Decomposition of MB under simulated solar light and regeneration of nanofibres.•Effective separation of nanofibres from the aqueous clean water by settling.

In this study, Degussa P25 TiO2 was partially dissolved in a mixture of hydrogen peroxide and sodium hydroxide at high pH. The fabrication of nanofibres proceeded by the hydrothermal treatment of the solution at 80 °C. This was followed by acid wash in HCl at pH 2 for 60 min, which resulted in the formation of hydrogen–titanate nanofibres. The nanofibres were annealed at 550 °C for 6 h to produce crystalline anatase nanofibres. The nanofibres were characterised for physico-chemical modifications and tested for the adsorption and photocatalytic degradation of methylene blue as a model water pollutant. An average specific surface area of 31.54 m2/g, average pore volume of 0.10 cm3/g and average pore size of 50 Å were recorded. The nanofibres were effective adsorbents of the model pollutant and adsorbents and good photocatalysts under simulated solar light illumination. No reduction in photocatalytic activity was observed over three complete treatment cycles, and the effective separation of nanofibres was achieved by gravity settling resulting in low residual solution turbidity.

Graphical abstractThe different steps of fabrication of HTNF using the peroxide method at a low hydrothermal temperature and their use in the photobleaching of coloured water.Figure optionsDownload full-size imageDownload high-quality image (104 K)Download as PowerPoint slide