Effective removal of high-chroma crystal violet over TiO2-based nanosheet by adsorption–photocatalytic degradation

TiO2-based nanosheet (TNS) was prepared by the alkaline hydrothermal treatment of P25, which was characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD) and nitrogen adsorption–desorption measurement. Its adsorption and regeneration properties for removal of high-chroma crystal violet (CV) were systematically investigated. The prepared TNS has much higher specific surface area of 207 m2/g and exhibits much stronger adsorption for CV than the raw material P25. The maximum adsorption capacity of TNS as determined from the Langmuir isotherm is 56.3 mg/g. The enhancement of adsorption capacity is ascribed to the increasing of specific surface area and surface hydroxyl groups, which can provide much more adsorption sites and stronger electrostatic attraction. It was further found that H2O2 can produce a synergetic photocatalytic degradation effect with TNS under UV–Vis irradiation, and the regeneration of TNS was effectively achieved by H2O2-assisted photocatalytic degradation process. The good reusability of prepared TNS in the cyclic adsorption–regeneration experiments indicates that it may be useful for dealing with dye wastewater.

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► TiO2-based nanosheet (TNS) was prepared by alkaline hydrothermal treatment of P25.
► TNS possesses high specific surface area and plenty of surface hydroxyl groups.
► The maximum adsorption capacity of TNS for CV was determined to be 56.3 mg/g.
► The H2O2-assisted photocatalysis can be explained by radical reaction mechanism.
► TNS exhibits good reusability for the removal of CV.