Modified coal tailings with TiO2 nanotubes and their application for methylene blue removal

Abstract Coal tailings are complex materials of low value that discharged from a coal-cleaning plant. These types of solid waste own great application prospects, but so far their utilization is still rare. Water pollution is another noteworthy problem in the world today. Organic pollutants such as dyes must be removed from the water. In the face of increasingly serious problems of water pollution and coal tailings reuse, it is an innovative method to treat organic wastewater with materials prepared by coal tailings. In this work, a series of TiO2 Nanotubes (TNTs) with Modified Coal Tailings (MCTs) prepared by different methods (including NaOH activation, H2SO4 activation and calcination) were successfully synthesized by a hydrothermal method using MCTs and Tetrabutyl titanate as starting materials. The different influencing factors on the photocatalytic performance of TNT-MCTs composites were characterized through XRD, SEM, EDS, TEM, UV–vis DRS, FT-IR and BET surface measurements. The UV–vis DRS spectra revealed that the absorption edge of TNTs is 387 nm, while that of TNT-MCTs photocatalysts redshifts up to 393 nm. The photocatalytic activity of TNT-MCTs was evaluated by the photocatalytic depigmentation of methylene blue solution (MB, 10 mg/L) under UV light irradiation. The specific surface area, surface roughness and activity of MCTs were increased after loading with TNTs. The degradation rate of MB reached 91% in 60 min under UV light illumination.