Adsorption-photocatalytic degradation of dye pollutant in water by graphite oxide grafted titanate nanotubes

Aiming at synthesizing titanate-based photocatalysts with high adsorption capacity and enhanced photocatalytic activity for dyes treatment, a new type of graphite oxide grafted titanate nanotubes (TNTs@GO) was prepared through a one-step hydrothermal method and characterized by a series of techniques including HRTEM , XRD , FTIR , XPS, etc. At the optimal GO loading (1 wt%), calcination temperature (300 °C) and time (0.5 h), TNTs@GO showed the highest photocatalytic activity for degrading Methylene Blue (MB, a model dye) under UV irradiation . Approximately 97.5% of MB was removed by TNTs@GO with 30-min pre-adsorption and 90-min UV irradiation. Radical scavengers quenching tests and electron paramagnetic resonance (EPR) measurements demonstrated several reactive species, i.e., h + , OH and O 2 - , played the critical roles in the photocatalytic process, and the presence of oxygen vacancy in TNTs@GO reduced the recombination rate of electron-hole pairs, thereby improving the photocatalytic activity. The effects of operational parameters were investigated, including TNTs@GO dosage, initial MB concentration, temperature, initial pH, humic acid and inorganic anions . Moreover, TNTs@GO showed a good reusability and applicability for multi-types of dyes. Therefore, TNTs@GO is a promising photocatalyst for dye wastewater treatment.